Written by Zithri Gabuya

Edited and Reviewed by Reuben J C. Los Baños, Ph.D.

A health information system is a tool that helps collect, store, manage, and share information about people’s health. It is used by doctors, nurses, hospitals, and health organizations to keep track of everything related to health care in an organized and easy-to-use way.

A health information system keeps records of things like:

• A person’s medical history, such as past illnesses, surgeries, or medications
• Visits to doctors or hospitals
• Vaccinations and test results
• Health programs and public health data

Instead of using paper files, most systems today use computers or special software to store this information safely and make it easy to find.

The people and organizations who use it are:

1. Doctors and Nurses – They use it to check patient information, write down what they observe, and follow treatment plans.
2. Hospitals and Clinics – They use it to manage appointments, store patient records, and make sure everyone gets the right care.
3. Government Health Departments – They use the information to understand public health problems and plan services like vaccination programs or emergency response.
4. Patients – In many systems, people can log in to see their own medical records, get reminders, or book appointments.

The benefits involve better care as doctors have the right information at the right time, which helps them make good decisions, along with faster service because electronic records are quicker to find than paper ones. Another is more safety, information is stored securely and backed up, so it is not lost. And lastly, health leaders can use the data to better plan programs and respond to health problems in the community.

These modern systems can remind people about check-ups or vaccines, let patients book appointments online, provide health advice or updates, and allow video calls with health professionals.

Health information systems are designed to keep personal health information private and safe. Only people who are allowed to see the information, like doctors or nurses, can access it. There are laws and rules that make sure your health records are protected.

A health information system is like a digital notebook that keeps track of a person’s health. It helps health workers provide better and faster care, and it helps governments plan better health services for everyone.

What is the importance of health information?

Health information is all the details about a person’s health. This includes things like past illnesses, doctor visits, test results, medicines, and treatments. It can also include things that affect a whole community, such as how many people are getting sick from a certain disease.

Having good health information is important because it helps people stay healthy and get the right care when they need it. When doctors and nurses have the correct information, they can make the right resolutions. They can give the correct treatment, avoid mistakes, and take care of people faster. For example, if a patient is allergic to a certain medicine, the doctor will know and avoid using it.

Health information also saves time. If someone visits a new doctor, that doctor can quickly learn about the patient’s past health without needing to ask too many questions. This helps avoid confusion and prevents repeated tests or delays in treatment.

This kind of information helps stop diseases before they spread. If many people in a community start getting the same illness, health workers can find out why and take action. They might provide vaccines, give advice on staying safe, or clean up a water supply if it’s the cause.

Governments use health information to make better plans. They can see what areas need more hospitals, where to send more doctors, or which health programs to support. This helps make sure everyone gets the care they need.

When people have access to their own health information, they can also take better care of themselves. They can remember appointments, keep track of their medicine, and talk more confidently with their doctor. It helps people learn about their health and make better choices.

Health information also helps prevent mistakes. If the records are clear and up-to-date, doctors don’t give the wrong medicine, and they don’t miss important details. This makes health care safer for everyone.

During emergencies like disease outbreaks or natural disasters, health information helps leaders know where to send help first. It shows which people are most at risk and helps them get the care they need quickly.

In simple words, health information is important because it helps everyone, from doctors to patients to governments, make smart, safe, and helpful decisions about health. It makes health care faster, better, and more organized for everyone.

What is the primary focus of the community health information system?

The primary focus of a community health information system is to collect, manage, and use health information to improve the health and well-being of people in a specific community.

This type of system looks at health data not just for one person, but for groups of people living in the same area, such as a neighborhood, village, town, or city. It helps health workers, clinics, and local leaders understand what health problems are common in the community, who needs help, and what services are needed most.

The main goal is to make sure that everyone in the community has access to the right care at the right time. It also helps in preventing illness, planning health programs, tracking diseases, and making smart decisions based on facts.

What is the role of the health information system in the health care system of the country?

The health information system plays a very important role in the health care system of a country. It helps make sure that health services are well-organized, efficient, and based on correct and current information.

This system collects and stores health data from hospitals, clinics, health workers, and communities. The information includes things like patient records, diseases, treatments, medicine use, births, deaths, and health services.

The health information system helps doctors and nurses by giving them quick access to patient details. With this information, they can better their assessments, avoid mistakes, and provide the right care.

It helps hospitals and clinics manage their daily work. They can keep track of appointments, test results, and patient treatments in a faster and more organized way.

It helps government health leaders understand the health needs of the population. They can use the information to plan health programs, provide services in the right places, and make important decisions that improve public health.

It helps prevent and control diseases by showing where and when health problems are happening. If a disease is spreading in a certain area, the system helps health workers act quickly to stop it. Just like what happened in the last pandemic.

It also helps save time and resources. For example, by using accurate information, health workers can avoid repeating tests or giving the wrong medicine. This helps the health care system work better and waste less.

The system can also help educate the public. Health messages, reminders, and updates can be shared with people based on their health needs.

Why is it important to protect information systems?

It is important to protect information systems because they hold valuable and private information that must be kept safe, accurate, and available when needed. If these systems are not protected, many serious problems can happen in health care, business, education, and other areas of occupation.

To Keep Personal Information Private

Information systems contain sensitive details, such as a person’s medical history, address, phone number, or financial information. If this data is not protected, it can be stolen or seen by people who should not have access to it, malpractice can occur. This can lead to identity theft, embarrassment, or harm to the individual.

To Prevent Mistakes and Protect Lives

In health care, information systems store data about patients, including test results, medicines, and allergies. If this information is changed, lost, or accessed by someone without permission, it could lead to wrong treatments or delays in care. Protecting the system helps keep the information correct and up to date.

To Keep Services Running Smoothly

If an information system is attacked or broken, significant services may stop working. Hospitals may not be able to access patient records, businesses may lose contact with customers, and

schools may lose student records. Protecting the system helps avoid service interruptions and delays.

To Build Trust

People need to trust that their personal information is safe. If an organization does not protect its information systems, people may lose trust and stop using its services. Protecting the system helps build and maintain said trust.

To Follow the Law

Many countries such as the Philippines have laws that require the protection of personal and health information. If an organization does not protect its systems, it may face legal problems, fines, or loss of its license. Following the rules helps keep the organization safe and respected.

To Protect Against Cyber Attacks

Hackers and criminals may try to break into systems to steal or damage information. Protecting information systems helps keep these people out and stops them from causing harm.

Conclusion

Health information systems are very important in helping people stay healthy. They make it easier for doctors, nurses, hospitals, and the government to take care of people. These systems help store and organize health records so that everyone can get the right care at the right time.

They help health workers with decisiveness, stop diseases from spreading, and plan better health services. They also save time and help avoid mistakes.

It is also very important to keep these systems safe. If they are not protected, private information can be lost or stolen, and people might not get the care they need.

In simple words, health information systems help make health care better, faster, and safer for everyone. When they are used and protected well, they help people live healthier lives.

REFERENCES

Health information systems. (2025, July 23). PAHO/WHO | Pan American Health Organization. https://www.paho.org/en/topics/health-information-systems

Almunawar, M. N., & Anshari, M. (2012, March 18). Health Information Systems (HIS): concept and technology. arXiv.org. https://arxiv.org/abs/1203.3923

Tedisel. (2022, December 14). The importance of health information systems. Tedisel Medical. https://tediselmedical.com/en/the-importance-of-health-information-systems/

Baker College. (2025, February 17). The role of health information Technology in modern healthcare.

https://www.baker.edu/about/get-to-know-us/blog/health-information-technology-role-mo dern-healthcare/

Jen, M. Y., Kerndt, C. C., & Korvek, S. J. (2023, June 20). Health Information Technology.

StatPearls – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK470186/ Sinhasane, S. (2025, April 30). What is Health Information System and & Its Significance in the

Healthcare                            Sector?                                              Mobisoft                          Infotech. https://mobisoftinfotech.com/resources/blog/importance-of-health-information-system/

Sinhasane, S. (2025, April 30). What is Health Information System and & Its Significance in the Healthcare                             Sector?                                              Mobisoft                          Infotech. https://mobisoftinfotech.com/resources/blog/importance-of-health-information-system/

The role of National health Information Systems in the response to COVID-19 – Johns Hopkins Coronavirus Resource Center. (n.d.). Johns Hopkins Coronavirus Resource Center. https://coronavirus.jhu.edu/from-our-experts/the-role-of-national-health-information-syst ems-in-the-response-to-covid-19

Epalm.        (2021,        August        25).        Interoperability        in        healthcare. HIMSS. https://www.himss.org/resources/interoperability-healthcare

Brook, C. (2018, June 18). What is a Health Information System? | Fortra’s Digital Guardian. https://www.digitalguardian.com/blog/what-health-information-system

Rights,    O.    F.    C.    (2022,    December   23).    Health   Information  Technology.              HHS.gov. https://www.hhs.gov/hipaa/for-professionals/special-topics/health-information-technolog y/index.html

Written by Kate Shanelle S. Bayawa

Edited and Reviewed by Reuben J C. Los Baños, Ph.D.

Physiology is the study of how the organs of the body work for it to function and maintain life. It helps you understand how organisms, organs, cells, and biomolecules work together to survive. This includes knowing how the heart, lungs, muscles, and brain do their tasks in your body.

The word “physiology” comes from the Greek words “physis,” meaning “nature” or “origin,” and “logia,” meaning “study of.”

Subdivisions of Physiology:

• Neurophysiology – the study of how the nervous system works.
• Cell Physiology – the study of how cells function together to maintain life.
• Organ physiology – the study of how a specific organ functions. (e.g., heart, kidney, lungs)
• Systemic Physiology – the study of how a specific organ system functions. (e.g., respiratory system, cardiovascular system, digestive system)
• Pathophysiology – the study of how injuries and diseases can cause changes to your body.
• Exercise physiology – study of the way the body responds to physical activities.

You can also apply this in real life:

• Treating Diseases – this will help you understand diseases and give you background on the proper way of treating it.
• First Aid and Response to Emergencies – it will help you know how to perform basic life-saving techniques, especially CPR since it relies on understanding the heart and lungs’ way of circulating oxygen.
• Diet Planning – since it explains how your body works, it will also let you understand how the body absorbs nutrients and this way, you’ll learn proper diet plan.

Is physiology part of biology?

Yes. Physiology focuses on a specific topic, which is learning the body’s function. On the other hand, biology is the study of life in general. Therefore, it is a subfield of biology because it studies the body’s organs’ tasks, whereas biology studies life as a whole.

However, it is not far from biology because it has its similarities. Biology studies all the living organisms while physiology focuses more on how cells, tissues, and organs perform their purpose to sustain life.

What is physiology vs. anatomy?

To simply understand the difference between these two. Physiology answers the question “How does it work?” and Anatomy answers the questions “What is it?” and “Where is it?”

Anatomy is the study of the structure of the body, while physiology studies how the body functions and the way the organs do its work.

For example, when you study the structure of your lungs, it falls under anatomy. However, when you study what the lungs’ responsibility in your body, then it falls under physiology.

Anatomy has its main divisions:

1. Gross (macroscopic) anatomy – study of easily observable structures or structures that can be seen by the naked eye. (e.g., lungs, heart, kidney)

Types of gross anatomy:

• Surface anatomy- study of the external features of the body (e.g., skin, muscles outlines)
• Regional anatomy – study of specific body regions (e.g., head, abdomen, chest)
• Systemic anatomy – study of the body systems (e.g., skeletal, reproductive, muscular)
• Microscopic anatomy – study of body structures that are too small to be seen with the naked eyes (e.g., cells and tissues)

Subdivisions of microscopic anatomy:

• Cytology– the study of cells
• Histology – the study of tissues

Who Discovered Physiology?

The discovery of physiology went through different stages that developed throughout the year. During the ancient beginnings, Egyptians, Greeks, and Indians were the one who dug deeper to know further about the human body.

There were people who had big contribution in discovering physiology, these people were

Hippocrates, Aristotle, and Galen.

• Hippocrates (460 BCE – 375 BCE) – also known as “the father of medicine” emphasized the idea that all diseases have its natural causes.
• Aristotle (384 BC – 322 BC) – studied how the living things functions.
• Galen (129 CE – 216 CE) – performed experiments to study how a specific organ work.

Physiology was not discovered by a single individual. It evolved over the centuries by the discovery of different ancient thinkers. They made a significant observation of the different functions of what’s inside your body.

Later, a physician named Jean Fernel first used the word “physiology” which led to the meaning “the study of the way the human body functions.”

Who is the father of physiology?

There is no specific individual who was referred to as “the father of physiology.” However, Claude Bernard is considered to as “the father of the modern physiology” because he had valuable contribution to the field and he introduced homeostasis.

Homeostasis – the body’s ability to maintain stability even though the outside world is continuously changing.

“Homeo” meaning “the same” and “Stasis” meaning “standing still.”

Albrecht von Haller is also considered as “the father of experimental physiology.” He is a Swiss biologist who was born in 1708. He made a contribution by discovering that muscles are “irritable” which means your muscle can move on its own without the need of processing or thinking about it.

He also discovered “sensibility” meaning that your nerves may not be able to move, but it can feel things such as temperature or when something is painful.

Why do we study physiology?

Studying physiology is important for the reason that it is one way of understanding how the body functions.

It will help you gain knowledge of how the inside of our body maintain for us to survive daily. If we don’t study physiology deeply, we cannot become knowledgeable about the way our organs do its task.

Benefits of studying physiology:

1. It helps us learn about how the human body works. It explains the following:
   • In what way does the heart and blood vessels circulate oxygen and nutrients throughout the body.
   • The way the lungs exchange gases between the body.
   • How the kidney filter waste and maintain fluid balance.
   • The way hormones regulate metabolism, growth, and reproduction.
2. It helps us learn about diseases that are broad or hard to understand

For example, in studying pathophysiology, it will allow us to learn why or how injuries and diseases can make changes in your body.

• You will understand why some heart diseases doesn’t only affect the heart but can also weaken the whole body.
• You will learn why high blood sugar is threatening.
• It helps prepare future health workers.
• It plays a crucial role especially to students who will go to med school, it provides deep understanding about the way our body functions.It builds knowledge of what really life is.
• It gives you advance knowledge or background on how to treat diseases.
• It helps you have better understanding of the Human BodyYou will understand how the body works. You will learn how the heart pumps blood.How the kidney filter waste.
• How the brain has controls to every actions.
• It encourages you to have a healthy living.
• It will help you realize how important balance diet and proper diet is.
• You will also learn how smoking, drinking of alcohol, and bad sleeping schedule could affect your health and how it can be sometimes life-threatening.

Why should you take physiology?

Taking this subfield of biology is important if you are planning to be a health worker. It advances your skills and knowledge on how the inside of your body do its task to survive every day.

If your plan is to be a doctor, a nurse, a medical technologist, a physical therapist, and other medical field works, it is important for you to take physiology. Additionally, it plays a significant role as it teaches basic knowledge and you will be able to learn theoretical knowledge.

It gives you background on how to assess, evaluate and track a patient’s health or condition. Studying this increases your awareness, especially in diseases that are common nowadays like diabetes.

Additionally, studying and taking this subject is crucial for you to become a professional and well-aware health worker in the future.

Here are examples of common conditions and explanations on why physiology is crucial in understanding the following conditions:

1. Asthma – It is a condition that affects your respiratory system, specifically your lungs and airways. In this subject, you will learn where oxygen is exchanged properly for carbon dioxide.
2. Heart attack – Since this subject will explain how the heart does its task to pump oxygenated blood; you will gain knowledge on what are its possible signs or signals.
3. Diabetes – This condition is one of the most common or known condition. In this subject, you will learn the role of pancreas in producing insulin normally.

Since this subject will teach you how the body works, it will also guide you on learning proper understanding and knowledge of CPR (cardiopulmonary resuscitation) that will be helpful for emergency situations.

Most importantly, this subject is not just for doctors and future health professionals but also for people in general. This allows you to apply knowledge on what really is going on inside your body.

Taking this subject, isn’t just about memorizing or just knowing the body parts and its function, but it is also about deeply understanding how it really works.

This subject doesn’t only teach us about what’s inside us humans and how our organs work for us to survive daily. This subject applies to all living organisms.

Conclusion

To sum it all up, physiology is one of the subjects that are important to take if you want to be a health worker. It briefly opens you in understanding life itself and the way it works. There are terms that are hard to understand but in studying physiology, it will be easy to understand.

More than just academic knowledge, it also helps us to understand lessons that may apply in real life situations. It encourages you to be aware and informed about your health, understand the signs that our body has been giving us.

In this subject, you will also learn to maintain your health and what to avoid for you to be far from diseases or conditions.

This will also teach you the backgrounds on what’s the right name of a specific diseases to avoid misinformation and it promotes wellness, prevent diseases, and aids in improving quality of our life.

This subject will also open you to the real life, it connects us to the bigger side of science. This subject is not just a subject that will help you in your future career.

This also a subject that will fosters curiosity, improves critical thinking and allow us to have deep understanding on what it is like to be alive. It does not matter if you are a healthcare professional or a student, studying this field will always be crucial. It pushes students to seek for answers in complex terms and understand the deeper reason why some people have that specific disease.

It is also a foundation of all Health Sciences, not just for medicine. This will also benefit nursing, pharmacy, physical therapy and medical technology as it will expose them to a broader knowledge about how everything inside our body works. It helps students acquire advance knowledge for students who will proceed to a medical school in the future.

It will also shape us on how we view health. It teaches and opens about the causes and effects of the diseases or conditions that are mistakenly understood.

Additionally, this subject will also let you recognize signs of diseases that may help you to be aware and get treatment as early as you can to avoid being in a critical condition

Lastly, in this subject, you will not just learn about life or how life works but it will also teach you what to avoid, to improve, protect, maintain what’s inside the body for you to survive. Not just that, it will also open you and give you broader knowledge of all living things and not just about humans. It encourages us to make healthier decisions to avoid life-threatening diseases or conditions.

References

Get A Professor. (2021, September 4). What do you mean by anatomy and physiology?https://getaprofessor.com/2021/09/04/what-do-you-mean-by-anatomy-and-physiology/amp

Cherney, K. (2023, July 27). What is physiology? Everything you need to know. Medical News Today. https://www.medicalnewstoday.com/articles/248791

Study.com. (n.d.). Human anatomy & physiology: Definition & relationship. https://study.com/academy/lesson/human-anatomy-physiology-definition-relationship.html

Service, R. F. (2017, April 11). The father of physiology. Science. https://www.science.org/content/article/father-physiology

Gonzaga University. (n.d.). Human Physiology Career Pathways. School of Health Sciences. Retrieved July 20, 2025, from https://www.gonzaga.edu/school-of-health- sciences/departments/human-physiology/human-physiology-career-pathways

American Physiological Society. (n.d.). What Is Physiology? Student Resources. Retrieved July 20, 2025, from https://www.physiology.org/career/teaching-learning-resources/student- resources/what-is-physiology?SSO=Y

Written by John Kyle D. Buenavista

Edited and Reviewed by Reuben J C. Los Baños, Ph.D.

The spinal cord is a key part of the central nervous system. It serves as the main link between the brain and the body. It sends signals that control movement, sensation, and reflexes. It makes it essential for how the body works. This article discusses the structure and function of the spinal cord. It also covers common disorders that affect it and ways to keep your spine healthy.

Structure of the Spinal Cord

It begins at the brainstem in the region known as the medulla oblongata. It runs down the spine to about the first or second lumbar vertebra (L1–L2) in adults. There, it narrows into the conus medullaris. Below this point, a bundle of nerves called the cauda equina goes down the lower vertebral canal. It allows for safe lumbar punctures.

The vertebral column protects the spinal cord. It is a bony structure with 33 vertebrae. Doctors divide these vertebrae into different regions:

• Cervical (Neck) – 7 vertebrae (CC1–C7)
• Thoracic (Upper Back) – 12 vertebrae (T1–T12)
• Lumbar (Lower Back) – 5 vertebrae (L1–L5)
• Sacral (Pelvis) – 5 fused vertebrae (S1–S5)
• Coccygeal (Tailbone) – 4 fused vertebrae (Co1)

The subarachnoid space sits between the arachnoid and the pia mater. It holds the cerebrospinal fluid (CSF), cushions the spinal cord, and helps remove Waste.

Function of the Spinal Cord

The spinal cord is a key communication highway. It carries signals from the brain to the body. Its primary functions include:

• Movement Control – Transmitting motor commands from the brain to muscles, allowing voluntary movement.
• Sensory Processing tells your brain when you feel touch, pain, or heat.
• Reflex Coordination – It controls quick, automatic actions. One example is the knee-jerk reaction.
• Autonomic Regulation – controls functions like heart rate, blood pressure, and digestion. It works through the autonomic nervous system.

Disorders of the Spinal Cord

Injuries or disorders can affect us. The spinal cord is essential for almost all body functions. Some common spinal cord disorders include:

• Spinal Cord Injury (SCI) is damage to the spinal cord. It can lead to partial or total loss of sensation and motor control.
  • Herniated Disks—The soft disks between your spine’s bones can bulge or tear. It can cause pain and pressure on the spinal cord or nerves.
  • Spinal Stenosis happens when the spinal canal narrows. It can squeeze the spinal cord, leading to pain or nerve problems.
  • Transverse Myelitis is when the spinal cord gets inflamed. It can cause paralysis and loss of sensation.

Maintaining Spinal Cord Health

To keep your spinal cord healthy and lower the chance of injury or disease, try these tips:

• Stay active, strengthen your core, and maintain good posture.
• Eat a Balanced Diet – Good nutrition helps keep your bones strong and your nerves working well.
• Practice Good Posture – Avoid prolonged slouching or awkward positions that strain the spine.
• Bend your knees to ensure a safe lift.
• Keep your back straight when picking up heavy things.
• Avoid Smoking and Drinking Too Much – These habits can harm bones and affect how nerves work.

What type of tissue do we find in the spinal cord?

The spinal cord is part of the central nervous system and is a crucial link between the brain and the body. It consists of nervous tissue, one of the four basic tissue types in the human body. The other types are epithelial, muscle, and connective tissues. Nervous tissue conducts electrical impulses and integrates sensory and motor information. This tissue supports key body functions like movement, reflexes, and organ control.

Nervous Tissue: The Core of the Spinal Cord

The spinal cord has two main parts: neurons and neuroglial cells.

• Neurons are the functional units of the nervous system. They are special cells that create and send electrical signals called nerve impulses. Spinal cord neurons send sensory information from the body to the brain. It sends motor commands from the brain to muscles and organs.
• Neuroglial cells (glial cells) provide neurons with support, protection, and nourishment. Types of glial cells in the spinal cord include astrocytes, oligodendrocytes, and microglia.

Researchers group spinal cord neurons by their functions. Neuroglial cells surround these neurons, keeping them healthy and protected. Without neuroglial cells, neurons would not function.

Gray Matter and White Matter

The spinal cord has two central regions of nervous tissue. Each one has its unique function:

• Gray Matter: Gray matter is in the center of the spinal cord. It looks like a butterfly when you look at it in cross-section. It consists of neuronal cell bodies, dendrites, and unmyelinated axons. This region handles synaptic integration. It processes information and coordinates reflexes. The Gray matter is essential for local communication within the spinal cord.
• White Matter: The white matter surrounds the gray matter. It has myelinated axons. Myelin is a fatty material made by oligodendrocytes. It wraps around axons and helps nerve impulses travel faster. White matter has two main types of tracts. Ascending tracts carry sensory information to the brain. Descending tracts send motor commands from the brain to the body. The presence of myelin gives this area its white appearance.

As the Cleveland Clinic describes, these tissues transmit messages between the brain and the rest of the body, allowing for voluntary movement, reflex actions, and involuntary autonomic functions like heart rate and respiration (Cleveland Clinic, n.d.).

More Supporting Tissues

Nervous tissue is the primary type in the spinal cord, but other tissues also help it work:

• Connective Tissue: The spinal cord has three layers of connective tissue. These layers are the meninges.
  • The three layers are:
    • Dura mater (outer layer)Arachnoid mater (middle layer)Pia mater (innermost layer)
    These layers help protect the nervous tissue and anchor the spinal cord.

• Epithelial Tissue: Ependymal cells are a kind of epithelial tissue. They run along the central canal of the spinal cord. They help create and transport cerebrospinal fluid (CSF). This fluid cushions and nourishes the spinal cord.

Clinical Relevance

Understanding the type of tissue in the spinal cord has important medical implications. Several problems can damage nervous tissue.

These include multiple sclerosis, spinal cord injuries, tumors, and infections. Damage to white matter blocks signals between the brain and body. In contrast, damage to gray matter affects reflexes and coordination.

Doctors perform lumbar punctures with great precision. They insert the needle below the L2 vertebral level. It helps prevent harm and lowers the risk to central nervous tissue.

What is the tissue between the spine?

The intervertebral disc is the tissue between the vertebrae in the spine. Fibrocartilaginous tissue makes these discs. They act like shock absorbers for the spine.

Structure of the Intervertebral Disc

Two main parts compose each intervertebral disc:

Annulus Fibrosus

• It is the tough outer layer of the disc made up of fibrous connective tissue.
  • It has several rings (lamellae) made of collagen fibers. These rings give strength and prevent excessive movement between vertebrae.
  • Its primary role is to contain and protect the softer inner part of the disc.
• Nucleus Pulposus
  • Located in the center of the disc, this is a gel-like substance with high water content.
  • It provides shock-absorbing features to the disc. It helps spread pressure when moving or bearing weight.
  • The nucleus pulposus can lose hydration as people age, making the disc less effective.

According to the University of Maryland Medical Center, this two-part structure allows the spine to handle compression and bending forces while maintaining its shape and flexibility (UMMC, n.d.).

Function of the Intervertebral Discs

• Shock Absorption: The discs absorb impacts during walking, lifting, and running.
• Spinal Flexibility: They enable bending and twisting movements of the spine.
• Discs create space between vertebrae. They prevent rubbing and let nerves exit the spinal canal without compression.

Clinical Relevance

Injury or wear to the intervertebral disc can lead to problems. These include herniated discs and degenerative disc disease. A herniated disc happens when the soft center of a spinal disc pushes out through a tear in the outer layer. It can press on spinal nerves, leading to pain, numbness, or weakness.

The intervertebral disc sits between the spine’s bones.

What are the soft tissues in the spinal cord?

The soft tissues in the spinal cord are:

• The spinal cord
• protective meninges
• intervertebral discs
• ligaments
• muscles
• tendons

These components protect the spinal cord, help movement, and maintain spinal stability. Breakdown of Soft Tissues:

• Spinal Cord: A column of nerves that transmits signals between the brain and the rest of the body.
• Meninges: Three protective layers surrounding the spinal cord:
• Dura mater: The tough outer layer.
• Arachnoid mater: The middle web-like layer.
• Pia mater: The delicate inner layer that fits around the spinal cord.
• Intervertebral Discs: Cushion-like pads between vertebrae that absorb shock and allow flexibility.
• Ligaments: Fibrous tissues connecting bones, providing stability to the spine.Muscles: Support the spine and ease movement.
• Tendons: Connect muscles to bones, aiding in movement and maintaining posture.

These soft tissues shield the spinal cord. They help with movement and support the body’s structure.

What are the three layers of connective tissue around the spinal cord?

The Three Layers of Connective Tissue Around the Spinal Cord

The brain and spinal cord comprise the central nervous system (CNS). Three layers of special connective tissue called the meninges protect them. These membranes support the structure, cushion the CNS, and block injury and infection.

The three meningeal layers, from outermost to innermost, are:

• Dura mater
• Arachnoid mater
• Pia mater

Dura Mater: The Tough Outer Layer

The dura mater is the outermost and most durable layer. It sits below the skull and spine. It has two layers: the outer periosteal layer connects to the bone. The inner meningeal layer is near the brain and spinal cord. This tough membrane serves as the primary protective shield for the CNS.

The dura mater also plays a vital role in venous drainage. It has channels called dural venous sinuses, which collect and drain blood from the brain. The dura mater also contains the middle meningeal artery, a key blood supply source. Plus, it offers a path for several cranial nerves, like the trigeminal nerve. Dural reflections are inward folds of the dura. They help anchor and compartmentalize the brain.

Arachnoid Mater: The Web-Like Middle Layer

The arachnoid mater sits below the dura mater. It is a thin, transparent membrane that looks like a spiderweb. Although avascular and lacking nerves, this layer is critical in cushioning the CNS. It spans the brain’s sulci and links to the pia mater below. Delicate strands called arachnoid trabeculae make this connection.

The subarachnoid space sits between the arachnoid and the pia mater. It has cerebrospinal fluid (CSF). CSF absorbs shocks, circulates nutrients, and removes Waste from the CNS.

Pia Mater: The Delicate Inner Layer

The pia mater is the innermost meningeal layer. It adheres to the brain and spinal cord, conforming to every fold and groove. The pia mater is delicate, but it has many blood vessels. These vessels go into the neural tissue to nourish the brain and spinal cord.

The pia mater supports the spinal cord’s structure. It also holds part of the CSF circulation system.

The Leptomeninges

We refer to the arachnoid and pia mater as the leptomeninges. It has a thin structure. This delicate layer works with the dura mater. Together, protect the CNS and support its function.

Meningeal Spaces and Their Functions

Three distinct spaces lie between or around the meningeal layers:

• Epidural Space: Space between the dura mater and the vertebral wall. It’s often used to give anesthesia during childbirth or surgery.
  • Subdural Space: This area sits between the dura and the arachnoid mater. It usually stays closed, but it can open up during trauma, like in a subdural hematoma.
  • Subarachnoid Space: This space is between the arachnoid and the pia mater. It holds CSF, which cushions and protects the CNS.

Functions of the Meninges

The meninges serve several vital roles:

• Protection: It shields the CNS from injury and stabilizes the skull’s brain.
  • Support: It houses and supports blood vessels, lymphatics, and nerves.
  • Storage: It nourishes, cushions, and cleans the brain and spinal cord.

Clinical relevance

Several medical conditions can affect the meninges:

• Meningitis: This is an infection that causes inflammation of the meninges. It usually shows symptoms like headache, fever, and neck stiffness.
• Meningiomas are usually benign tumors that originate from meningeal tissue. Yet, they can sometimes grow big enough to cause neurological symptoms.
• Subdural Hematoma: This is bleeding that occurs between the dura and arachnoid mater. It often happens after head trauma.
• CSF Leak: A tear in the dura mater allows CSF to escape. It can lead to severe headaches and other issues.
• Meningeal Carcinomatosis is a rare but serious condition. In this case, cancer spreads to the meninges from another primary site.

What is the purpose of cerebrospinal fluid?

Cerebrospinal fluid (CSF) is a clear, watery fluid that flows around the brain and spinal cord. It plays a key role in protecting and supporting the central nervous system (CNS).

Where CSF Comes From

A group of cells in the choroid plexus makes CSF in the brain’s ventricles. The body produces approximately 400–600 mL of CSF each day, but only around 150 mL exists in the body at the same time. CSF undergoes regular absorption and replacement.

Main Functions of CSF

Protects the Brain and Spinal Cord

CSF works like a cushion. It protects the brain and spinal cord from injury. It absorbs shocks from falls or sudden movements. It also supports the brain by making it “float,” which reduces pressure on the lower parts of the brain.

Keeps the Environment Stable

The brain requires a stable environment to function. CSF helps control the amount of salt, sugar, and other substances around brain cells. It also removes harmful waste products that build up as the brain works.

Delivers Nutrients

CSF supplies the brain and spinal cord with nutrients such as glucose (sugar) and vitamins. It also helps move chemical messengers, like hormones and signals, between brain parts.

Removes Waste

As brain cells do their job, they produce Waste. CSF helps remove Waste, including cells, toxins, and byproducts from neurotransmitters.

What’s in CSF?

Compared to blood, CSF has:

• More sodium and chloride
• Less potassium and calcium
• Very little protein
• Almost no red blood cells (and very few white blood cells— less than 5)

Why CSF Matters in Medicine

Doctors often collect CSF through a lumbar puncture or spinal tap. This test checks for diseases of the brain and spine.

Some essential conditions related to CSF include:

• Meningitis: An infection that causes swelling in the brain coverings. CSF can show signs of bacteria or viruses.
• Hydrocephalus: When CSF builds up too much in the brain, it causes pressure.
• CSF Leak: If CSF leaks out, it can cause nasty headaches.
• Subarachnoid Hemorrhage: This is bleeding into the CSF spaces. It often happens after a head injury or a burst blood vessel.

In Summary

Cerebrospinal fluid is vital for:

• Protecting the brain and spinal cord
• Nourishing brain tissues
• Removing waste products
• Helping doctors diagnose brain problems

Without CSF, the brain couldn’t work or stay safe from injury.

Is the spinal cord an organ or tissue?

The spinal cord is a key part of the central nervous system. It sends signals from the brain to the body and back.

We will examine the spinal cord, covering its structure, function, and common disorders. We will also discuss ways to keep your spine healthy.

Structure of the Spinal Cord

The spinal cord is a long, tube-like structure made of nervous tissue. It runs from the brainstem to the lower back and ends at the conus medullaris. Protective layers called meninges surround the brain.

These layers, from outermost to innermost, include:

1. Dura Mater – The rigid, outermost layer that shields the spinal cord from physical damage.
2. Arachnoid Mater – This middle layer looks like a web. It cushions and protects the spinal cord.
3. Pia Mater – This is the thin layer that hugs the spinal cord. It brings blood vessels to nourish the cord.

The vertebral column also protects the spinal cord. This bony structure has 33 vertebrae divided into three central regions:

• Cervical (Neck) – 7 vertebrae
• Thoracic (Upper Back) – 12 vertebrae
• Lumbar (Lower Back) – 5 vertebrae

Disorders of the Spinal Cord

Injuries or disorders can affect us. It is because the spinal cord is crucial for almost all body functions. Some common spinal cord disorders include:

• Spinal Cord Injury (SCI) happens when the spinal cord gets damaged. It can lead to a loss of feeling or control of movement; in some cases, the loss is partial, while in others, it is total.
• Herniated Disks happen when the disks that cushion the vertebrae bulge or break. They press on the spinal cord or nerves.
• Spinal Stenosis occurs when the spinal canal narrows. This can squeeze the spinal cord, causing pain or nerve issues.
• Transverse Myelitis occurs when the spinal cord becomes inflamed. It can lead to paralysis and loss of sensation.

Maintaining Spinal Cord Health

To keep the spinal cord healthy and reduce the risk of injury or disease, consider the following tips:

• Do exercises that build core muscles and improve posture.
  • Eat a Balanced Diet – Maintain proper nutrition to support bone health and nerve function.
  • Practice Good Posture – Don’t slouch or stay awkward for too long. It can strain your spine.
  • Use Proper Lifting Techniques – Bend your knees, not your back, when lifting heavy objects.
  • Avoid Smoking and Drinking Too Much – These habits can harm bones and affect how nerves work.

References

Cleveland Clinic. (n.d.). Spinal cord. Retrieved May 4, 2025, from https://my.clevelandclinic.org/health/body/21946-spinal-cord

Cleveland Clinic. (n.d.). Spine: Anatomy, function, parts, segments & disorders.

Gerson & Schwartz, P.A. (n.d.). Is the spinal cord an organ? Injury Attorneys. Retrieved May 10, 2025, from https://www.injuryattorneyfla.com/blog/is-the-spinal-cord-an-organ/

Mayo                  Clinic.                  (n.d.).                  Meninges.                  Retrieved              from https://www.mayoclinic.org/diseases-conditions/meningioma/multimedia/meninges/img-2 0008665

Professional, C. C. M. (2024, December 19). Spinal cord. Cleveland Clinic. Retrieved from https://my.clevelandclinic.org/health/body/21946-spinal-cord

Professional, C. C. M. (2025, January 24). Spine structure and function. Cleveland Clinic. Retrieved                                                                                                                       from

https://my.clevelandclinic.org/health/body/10040-spine-structure-and-function

Professional, C. C. M. (2025, March 19). Meninges. Cleveland Clinic. Retrieved from https://my.clevelandclinic.org/health/articles/22266-meninges

Telano LN, Baker S. (2023, July 4). Physiology, Cerebral Spinal Fluid. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from https://www.ncbi.nlm.nih.gov/books/NBK519007/

U.S. National Cancer Institute SEER Training. (n.d.). Nervous tissue. Retrieved May 4, 2025, from https://training.seer.cancer.gov/anatomy/cells_tissues_membranes/tissues/nervous.html

University of Maryland Medical Center. (n.d.). Anatomy and Function of the Spine. Retrieved May                       4,                                       2025,                                              from https://www.umms.org/ummc/health-services/orthopedics/services/spine/patient-guides/a natomy-function#:~:text=Intervertebral%20Disc,center%20called%20the%20nucleus%2 0pulposus

Written by Chrissel Kate B. Cadungog

Edited and Reviewed by Reuben J C. Los Baños, Ph.D.

The respiratory system includes the epithelium and connective, muscular, and nervous tissues. Each has a distinct role in breathing and protecting the airway.

There are many human tissues involved in respiration and keeping the airways open. Four tissue types are found within the entire respiratory system:

• Epithelial Tissue – Covers airways and alveoli. It serves to protect, produce mucus, and facilitate gas exchange.
• Connective Tissue – Found in cartilage, blood vessels, and elastic fibers. These elements give the lungs and airways their form, support, flexibility, and the ability to transport materials.
• Muscle Tissue – There are smooth and skeletal muscles in this system. Smooth muscle controls the diameter of the airways and diaphragm, whereas the skeletal muscle controls breathing.
• Nervous Tissue – Controls the breathing rhythm and reacts to chemical stimuli such as CO₂ levels.

These tissues function collectively in an orchestrated way to sustain the function of the lung. For instance, mucus covering the top of the epithelium is cleaned up by epithelial cilia, and smooth muscle contracts during bronchoconstriction. They communicate with one another to achieve an efficient exchange of gases, airway clearance, and lung mechanics.

What tissue is in the upper respiratory tract?

The upper respiratory tract is predominantly covered by pseudostratified ciliated columnar epithelium containing goblet cells, and stratified squamous epithelium.

The predominant tissue type in the upper respiratory tract (i.e., nasal cavity, pharynx, and larynx) is pseudostratified ciliated columnar epithelium. This epithelium carries out several functions:

• Cilia move mucus and trapped particles toward the throat.
• Goblet cells secrete mucus that traps dust and microbes.
• The structure appears multilayered but is a monolayer with nuclei at different heights.

The oropharynx and laryngopharynx are the regions where stratified squamous epithelium is found. Such multilayered tissue is required to withstand the friction generated by ingested food and varying air temperatures. Cartilage, loose connective tissue, and skeletal muscle, such as that in the pharyngeal wall, make up the deeper structures.

These tissues ensure cleaning, moisturizing, and warming of the incoming air while protecting the deeper structures from mechanical damage and microbial invasion.

What type of connective tissue is found in the respiratory tract?

The walls of the respiratory passages comprise loose connective tissue, elastic connective tissue, and hyaline cartilage.

The function of connective tissues in the epithelial lining of the respiratory system is varied. The most common types are:

• Areolar (loose) connective tissue: Located under epithelial layers. It supports and binds tissues together, delivers nutrients via blood vessels (vascular supply), and houses immune cells.
• Elastic connective tissue is present in the lungs and small bronchi. It permits the lungs to expand while breathing in and contract while breathing out. This elastic recoil is essential for passive expiration.
• Hyaline cartilage: Located within the trachea and bronchi. It prevents airway collapse and ensures that passageways remain open for the controlled airflow and oxygen intake.
• Fibroelastic connective tissue: Found within the epiglottis and vocal cords. It gives flexibility and strength.
• Reticular connective tissue: Surrounds the alveoli and in the walls of capillaries, and supports thin structures such as beds of capillaries.
  
  

These connective tissue components define the structure’s mechanical properties regarding elasticity, durability, and structural integrity for the respiratory system.

What kind of tissue is the cartilage in the respiratory system?

The cartilage in the respiratory system is hyaline cartilage, which maintains open airways. The hyaline cartilage can be found in the trachea, bronchi, and larynx.

Hyaline cartilage is a fundamental structure in maintaining airway integrity. It comprises chondrocytes embedded in a glassy matrix rich in type II collagen and proteoglycans. This cartilage appears as C-shaped cartilage rings, preventing the trachea from collapsing during inspiration while allowing the esophagus to expand during swallowing. In the bronchi plates, hyaline cartilage maintains bronchi diameter and resists collapse during respiration. Structures in the larynx contain hyaline (e.g., thyroid, cricoid) and elastic cartilage (e.g., epiglottis). Unlike elastic cartilage (e.g., in the ear), hyaline cartilage is more rigid and better suited for mechanical support.

Where is pseudostratified columnar epithelium found?

Pseudostratified columnar epithelium is mainly found in the respiratory tract’s nasal cavity, trachea, and upper bronchi.

This epithelial tissue is pseudostratified because its cells appear in multiple layers, but all touch the basement membrane. This epithelium is specially adapted for air filtration. It contains hair-like projections that beat coordinatedly to move mucus toward the pharynx, called cilia. Goblet cells embedded in the tissue produce mucus rich in glycoproteins that traps particles like dust and pathogens.

You will find this tissue in:

• Nasal cavity
• Paranasal sinuses
• Nasopharynx
• Larynx
• Trachea
• Primary and secondary bronchi

This epithelium functions as a mechanical and immunological barrier, preventing contaminants from reaching the delicate lower airways. Damage to this epithelium, such as from smoking, impairs mucociliary clearance and increases infection risk.

Where can stratified squamous epithelium be found in the respiratory system?

Stratified squamous epithelium of the respiratory system is mainly found in the oropharynx, laryngopharynx, and superior portions of the larynx, which are usually exposed to abrasion.

This type of epithelium is present in your respiratory system organs, which are subjected to physical impact. These organs are:

• Oropharynx (immediately posterior to the oral cavity)
• Laryngopharynx (region bounded in between the hyoid bone and the esophagus)
• Upper region of the larynx (as well as the vocal folds)

A healthy respiratory tissue is classified as non-keratinized stratified squamous epithelium. However, this tissue could become keratinized with cycles of chronic damage (e.g, cigarette smoke or other irritants). An adaptive change of this kind is metaplasia, which can increase the chance of dysplasia or carcinoma.

Is there muscle tissue in the respiratory system?

Yes. The respiratory system regulates airway resistance through smooth and skeletal muscle tissues. These tissues also drive ventilation.

Your respiratory system involves two types of muscle tissue:

• Smooth muscles – Found within the walls of the bronchi, bronchioles, and arterioles. These involuntary muscles contract or relax, modulating airway diameter and resisting airflow. Smooth bronchial muscle is contracting excessively during any asthma attack. Histamine or acetylcholine provokes a response using neural and chemical signals.
• Skeletal muscles – Present in the muscles of the diaphragm, intercostal muscles, and the pharynx and larynx. These muscles are necessary for inhalation, exhalation, speech, and swallowing. Control is voluntarily exerted over them.

The autonomic nervous system and somatic nervous system regulate muscle activity. This ensures that breathing continues consciously and unconsciously. Smooth muscle malfunctions act to play a role in asthma and chronic obstructive pulmonary disease (COPD), while paralysis in the diaphragm causes respiratory failure.

How do these tissues work together in the respiratory system?

Your respiratory tissues work together to provide structural support, protection, gas exchange, and air movement. This tissue collaboration guarantees that your respiratory system effectively performs its primary functions.

• Incoming air is filtered and humidified by epithelial tissues.
• Connective tissues preserve lung elasticity and airway shape.
• Muscle tissues generate the movement of air into and out of the lungs.
• Nervous tissues coordinate both voluntary and automatic breathing.

This tissue synergy maintains homeostasis. A disruption in one tissue type frequently causes respiratory dysfunction. For instance, in emphysema, damaged elastic fibers make it difficult to exhale, and loss of epithelial cilia raises the risk of infection.

Clinical relevance of tissue interactions

• The thickening of the epithelium and excessive mucus production are symptoms of chronic bronchitis.
• Asthma patients experience bronchoconstriction due to smooth muscle hyperactivity
• Airway collapse, especially in tracheomalacia, is caused by cartilage loss.
• The breakdown of the elastic connective tissue in the alveolar walls causes emphysema.
• Squamous metaplasia brought on by irritants can result in laryngeal cancer.
• Hypoventilation may result from nerve damage that impairs diaphragm control.

To maintain the best possible respiratory health, every tissue in the respiratory system cooperates with the others. The entire system is frequently impacted when one type of tissue is disrupted.

Changes in these tissues are frequently the focus of diagnostic procedures like bronchoscopy, CT scans, and histology. Surgery, anti-inflammatory drugs, and bronchodilators are among the treatments that rely on tissue-specific pathology.

Conclusion

The proper coordination of epithelial, connective, muscular, and nervous tissues controls all respiratory system parts. These tissues help to filter impurities in the air, keep your body strong and stable, facilitate movement, and manage certain physiological activities.

In clinical practice or in your studies, understanding how each of these tissues functions alone and in combination will give you a better grasp of respiratory physiology and pathology. Studying histology taught me to appreciate how the body can preserve such a sensitive process as breathing, naturally, unthinkingly, all day, for years. Understanding how a single cell layer in a trachea or a single muscle fiber in a diaphragm can determine your entire supply of oxygen can make you feel grateful, or it can make you feel inspired. I encourage you to learn more about these tissues and their role in health problems and diseases.

Whether you are a medicine, biology, or health sciences student, learning about these tissues will provide a solid foundation for understanding respiratory anatomy and physiology.

REFERENCES

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Written by Kiara Aleksy T. Paglinawan

Edited and Reviewed by Reuben J C. Los Baños, Ph.D.

Skeletal muscle is a striated, multinucleated, and voluntary type of muscle tissue. Out of the three types of muscle tissue, skeletal muscle is the most abundant in the human body. It comprises about 30% to 40% of your body mass, with males having more than females.

They connect to bones directly or through tendons, which are connective tissues. They are responsible for a variety of functions. Skeletal muscles produce voluntary movements, meaning you control how and when they work. They consist of flexible fibers that contract, which allows the muscles to move bones.

This tissue has long, cylindrical muscle fibers. These fibers group into bundles known as fascicles. Each muscle fiber contains myofibrils that consist of repeating sarcomeres.

Sarcomeres are the functional units of contraction, consisting of actin and myosin filaments. These microscopic structures give skeletal muscle its striated appearance under a microscope.

A connective tissue layer called the epimysium surrounds the entire muscle. The perimysium encloses each fascicle, while the endomysium wraps around individual muscle fibers.

This structured design helps with efficient contraction and force transmission. It also protects your muscles during physical activity.

Skeletal muscles also have special properties that help them do their jobs well. These properties make movement smooth, fast, and controlled.

Properties of skeletal muscle:

1. Extensibility. Muscles can stretch without damaging themselves. This allows your body to move in many directions.
2. Elasticity. Muscles can stretch or shorten, then return to their normal shape and size.
3. Excitability. Muscles respond to signals from the brain and nerves. This is how you control movement.
4. Contractility. When muscles receive signals, they shorten or contract. This action pulls on bones and creates movement.

These four properties work together every time you move. When you extend your arm to grab something up, your muscles first stretch. When you grip the object, your muscles contract. Afterward, they return to their original shape, ready for the next action.

These abilities are not only useful for motion. They also help keep balance, protect joints, and hold your posture. Without these muscle traits, it would be difficult to walk, sit, or even smile.

Skeletal muscles fall into two main types: red and white. This classification is based on their function and appearance under a microscope.

1. Red Muscles (Slow-Twitch Fibers)

These muscles get their red color from myoglobin, a protein that stores oxygen. They contain many mitochondria, the energy powerhouse of the cell. These help the muscles work for a long time without getting tired.

Red muscles are;

• smaller in size
• rich in oxygen and blood supply
• built for endurance and steady activity

2. White Muscles (Fast-Twitch Fibers):

White muscles have less myoglobin and fewer mitochondria. They are bigger in size and work better for fast, powerful actions.

White muscles are;

• larger in size
• quick to act but get tired easily
• used for strength and speed

You use white muscles when sprinting, jumping, or lifting heavy objects. These muscles work fast but need more time to rest.

Both red and white muscles are important. Most of your skeletal muscles contain a mix of both types. The exact amount depends on your genetics and the kind of activity you often do. Athletes who run marathons usually have more red fibers. Sprinters or weightlifters tend to have more white fibers.

Knowing these muscle types also helps in exercise and health. Training can make your muscles stronger or increase their endurance. Regular exercise won’t change one muscle type into another, but it helps your muscles work better.

Skeletal muscles are strong, flexible, and responsive. Their properties help them stretch, contract, and return to shape. Their types support both steady movements and sudden actions.

What are the characteristics of skeletal muscle?

Skeletal muscles typically connect to bones through tendons. These connections help generate movement whenever your muscles contract. Tendons act as strong cords that conduct force to the skeleton.

Skeletal muscles are long and cylindrical in shape. They are often called muscle fibers and can extend the full length of a muscle. Connective tissues bundle these cells together.

Each muscle cell has many nuclei. This allows the cell to produce large amounts of proteins. Enough amount needed for contraction and repair.

You can see striations when viewed under a microscope. Striations are visible as light and dark bands. These bands come from the arrangement of actin and myosin filaments in sarcomeres.

Skeletal muscles contract through a well-known process. The sliding filament theory is the mechanism by which muscle contracts at the cellular level. In this process, actin and myosin filaments slide past each other to shorten the muscle fiber.

Skeletal muscles are under voluntary control. This means you can move them in a conscious state, unlike cardiac or smooth muscle. Movements like walking, running, lifting, and facial expressions rely on these muscles.

Each muscle cell has a membrane called the sarcolemma. This membrane keeps the cell’s shape and sends signals that trigger muscle contraction.

Muscle cells store energy and oxygen using specialized structures. Glycosomes store glycogen for energy. Myoglobin holds oxygen for use during activity.

Inside the muscle fiber, you’ll find myofibrils that carry out contractions. These myofibrils contain sarcomeres, the smallest units of muscle contraction.

Muscle cells also have sarcoplasmic reticulum dedicated to calcium ions (Ca2+) handling. This specialized form releases calcium when the muscle needs to contract. It pumps calcium back in when the muscle relaxes.

T-tubules run deep into the muscle fiber, enhancing cellular communication. Transverse tubules are invaginations of the sarcolemma. They bring the sarcolemma very close to the sarcoplasmic reticulum. This setup helps the rapid spread of Ca2+ ions. This synchronized release allows muscles to contract with more force.

What is the function of skeletal tissue?

Skeletal muscles are a vital part of your musculoskeletal system.

These muscles pull on bones to create movement. Every time you walk, lift, or reach, your skeletal muscles work to move your body. They contract with force, allowing fast and precise actions.

These muscles also keep your body in position. Even when you’re standing still, they contract to support your posture. Without them, your spine and joints would collapse under your weight.

Skeletal muscles help control body temperature. When they contract, they release heat as a by-product. This keeps your body warm, especially during cold conditions.

Muscles also play a role in breathing. The diaphragm, which is a skeletal muscle, moves air in and out of your lungs. Other muscles in your chest assist with deeper or forced breathing.

They support facial expressions and speech. Tiny muscles in your face allow you to smile, frown, or speak clearly. Voluntary skeletal muscle contractions control each movement.

These muscles assist in swallowing and digestion. Skeletal muscles are found at the openings of internal tracts. They control the voluntary movement of substances like food, urine, and stool. This makes swallowing, urination, and defecation possible under conscious control.

Other functions include tasks that are seldom discussed but hold equal importance:

Skeletal muscle releases myokines during contraction. Myokines are proteins made by muscle cells when you move. They help your body respond to physical activity. They also support growth, healing, and disease protection.

Myokines affect energy metabolism and inflammation. They play a role in the development of metabolic diseases like type 2 diabetes. Some myokines improve insulin sensitivity and glucose use. They help regulate both sugar and fat metabolism.

Skeletal muscle supports energy balance in your body. It stores sugar and fat for later use. This keeps energy levels stable during rest or movement.

Where is skeletal muscle found?

You can find skeletal muscles throughout your body. They connect to bones using tendons and pull on them to create motion. This includes both large and small movements across joints.

In the head and neck, skeletal muscles help move the eyes, chew food, and create facial expressions. Muscles like the frontalis and orbicularis oris help you express emotions. The sternocleidomastoid turns and flexes your neck.

The trunk houses muscles like the intercostals and diaphragm, which assist in breathing. Back muscles such as the erector spinae stabilize your spine and support posture.

Your upper limbs have muscles like the biceps brachii, triceps brachii, and deltoid. They help you lift, push, and pull. The lower limbs have the quadriceps femoris, hamstrings, and gastrocnemius. They help you walk, run, and jump.

Skeletal muscles play roles in breathing, locomotion, and communication. They allow you to sit upright, walk, talk, and even smile. Their broad distribution is essential for both function and form.

Do skeletal muscles protect internal organs?

Yes, skeletal muscles protect internal organs. These muscles do more than move your body. They provide support and absorb physical impacts.

Your striated muscles in the abdomen, chest, and pelvis create layers. These layers protect the soft tissues underneath.

Your abdominal area has muscles like the rectus abdominis, obliques, and transversus abdominis. These muscles help protect the stomach, liver, intestines, and kidneys. These muscles hold the organs in place and absorb shocks from outside forces. They also increase abdominal pressure to help with stability and posture.

In the chest, the pectoralis major and the muscles between the ribs help protect the heart and lungs. They form a muscular layer beneath the ribs, adding another level of support. These muscles also aid in breathing and upper limb movement.

In the pelvic area, skeletal muscles like the levator ani form the pelvic floor. They support organs such as the bladder, uterus, and rectum. Without these muscles, organs would shift or prolapse over time.

Muscles respond quickly to protect the body. For example, when you sense danger, muscles tense up to shield vital areas. This shows how protection is an active role, not a mere side effect.

How does skeletal muscle tissue contribute to body temperature?

Skeletal muscles help keep the body in balance by generating heat.

Muscle contractions need energy in the form of ATP. When ATP breaks down, it produces heat. This is especially noticeable during exercise. As muscles move, body temperature rises. In extreme cold, shivering causes random muscle contractions, which also generate heat.

As your muscles work harder, more heat builds up. This is why your body feels warmer and you start sweating during physical activity. The heat keeps your internal environment stable even in cold surroundings.

When you’re cold, your body reacts by making muscles contract rapidly. This reaction is called shivering.

These small movements create heat and help raise your body temperature.

Yet, too much heat from muscle contractions can be dangerous. There is a rare condition called malignant hyperthermia. It happens in people who are genetically sensitive to certain anesthesia drugs.

In these individuals, skeletal muscles release too much calcium. This leads to sustained contractions and extreme heat buildup. Because the person is asleep under anesthesia, they cannot cool themselves.

Without quick treatment, their body temperature rises too high and may cause death. That’s why doctors ask about family history before surgery. Early awareness can prevent this medical emergency.

Skeletal muscle is not only for movement. It is also essential in keeping your temperature balanced.

Which food will increase body muscle?

Don’t get distracted by the protein powder propaganda. You can get plenty of muscle-building nutrients by adding the right foods to your diet. To build muscle, you must eat the right foods. Good nutrition gives you the energy you need to thrive.

It becomes important to consume foods that help you build muscle mass. This includes protein-rich foods, along with essential carbs and fats.

Here are some foods that contribute to natural muscle building:

1. Eggs: eggs are the perfect protein source. They contain healthy fats and key nutrients like vitamin B and choline. Eggs contain large amounts of the amino acid leucine. This is key for helping your body make protein, which boosts muscle gain.

• Lean beef: beef is packed with high-quality protein, B vitamins, minerals, and creatine. It also contains saturated fats that help to maintain healthy testosterone levels. It is an androgenic hormone that is very important for building muscle mass.

• Chicken breast: it is a viable source of protein as chicken contains the highest amount of it. Each 3-ounce (85-g) serving contains about 26.7 g of high-quality protein. A 2018 study found that eating chicken after exercise can aid in fat loss. It may also boost muscle mass and strength.

• Salmon: it is great for your health and is an excellent choice for building muscle. A 3-ounce (85-g) serving of salmon has about 17 g of protein, 1.5 g of omega-3 fatty acids, and several key B vitamins.

• Greek yogurt: it is a mixture of fast-digesting whey protein and slow-digesting casein. Greek yogurt has more protein (20 g per serving) compared to regular yogurt (16 g per serving).

• Quinoa: you also need energy for your activities. Foods with carbohydrates can help provide this energy. Cooked quinoa has about 40 g of carbs in a cup (185 g). It also offers 8 g of protein, 5 g of fiber, and good amounts of magnesium and phosphorus. Magnesium is important for your muscles and nerves.

Skeletal muscle is more than a tissue of movement. It is a complex, dynamic system essential for human life. It moves, protects, warms, and even heals. Understanding its workings reveals its pivotal role in maintaining strength and balance.

References:

Professional,        C.         C.         M.         (2025,        April       17).        Skeletal       muscle.               Cleveland       Clinic. https://my.clevelandclinic.org/health/body/21787-skeletal-muscle

Rossi, D., Pierantozzi, E., Amadsun, D. O., Buonocore, S., Rubino, E. M., & Sorrentino, V. (2022). The sarcoplasmic reticulum of skeletal muscle cells: a labyrinth of membrane contact sites. Biomolecules, 12(4),

488. https://doi.org/10.3390/biom12040488

Wikipedia                contributors.                (2025,                March               16).                T-tubule.                  Wikipedia. https://en.wikipedia.org/wiki/T-tubule#:~:text=As%20T%2Dtubules%20bring%20the,cells%20to%20contr act%20more%20forcefully

Balakrishnan, R., & Thurmond, D. C. (2022). Mechanisms by which skeletal muscle myokines ameliorate insulin resistance. International Journal of Molecular Sciences, 23(9), 4636. https://doi.org/10.3390/ijms23094636

Iizuka, K., Machida, T., & Hirafuji, M. (2014). Skeletal muscle is an endocrine organ. Journal of Pharmacological Sciences, 125(2), 125–131. https://doi.org/10.1254/jphs.14r02cp

Betts, J. G., Young, K. A., Wise, J. A., Johnson, E., Poe, B., Kruse, D. H., Korol, O., Johnson, J. E., Womble, M., & DeSaix, P. (2022, April 20). 10.2 Skeletal Muscle – Anatomy and Physiology 2E | OpenStax. https://openstax.org/books/anatomy-and-physiology-2e/pages/10-2-skeletal-muscle

Admin. (2021, March 8). Skeletal muscle. BYJUS. https://byjus.com/biology/skeletal-muscle/

Upper           limb           muscles           and           movements.           (2023,           November           13).       Kenhub. https://www.kenhub.com/en/library/anatomy/upper-limb-muscles-and-movements

Lower                   limb                   anatomy.                   (2023,                  September                  11).               Kenhub. https://www.kenhub.com/en/library/anatomy/lower-extremity-anatomy

Facial muscles. (2023, November 21). Kenhub. https://www.kenhub.com/en/library/anatomy/the-facial-muscles

Sternocleidomastoid                     muscle.                    (2023,                    October                    30).                                        Kenhub. https://www.kenhub.com/en/library/anatomy/sternocleidomastoid-muscle

Erector                  spinae                  muscles.                  (2023,                  November                  3).                Kenhub. https://www.kenhub.com/en/library/anatomy/erector-spinae-muscles

Dave, H. D., Shook, M., & Varacallo, M. A. (2023, August 28). Anatomy, skeletal muscle. StatPearls – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK537236/

CCCOnline.                   (n.d.).                   Muscular                   system                   homeostasis.                         Pressbooks. https://pressbooks.ccconline.org/bio106/chapter/muscular-system-homeostasis/

Sharp, M. H., Lowery, R. P., Shields, K. A., Lane, J. R., Gray, J. L., Partl, J. M., Hayes, D. W., Wilson, G. J., Hollmer, C. A., Minivich, J. R., & Wilson, J. M. (2017). The effects of beef, chicken, or whey protein after workout on body composition and muscle performance. The Journal of Strength and Conditioning Research, 32(8), 2233–2242. https://doi.org/10.1519/jsc.0000000000001936 Cissn, G. T. P. C. (2024, February 15). 26 foods to eat to gain muscle. Healthline. https://www.healthline.com/nutrition/26-muscle-building-foods#muscle-building-foods

Written by Gynne Ross Q. Ancheta

Edited and Reviewed by Reuben J C. Los Baños, Ph.D.

Have you ever wondered what our hair is composed of? Let me take you back to the basics! It is composed of a protein called keratin, a fibrous structural protein.

In the hustle and bustle of life, we tend to get overwhelmed by chores and issues and forget to stop for a moment to enjoy the little marvels that abound. But occasionally, in the simplest of things—such as a single strand of hair—we see beauty, intricacy, and even a lesson in slowing down.

Is it only found in your hair? No. Keratin is also found in your skin and nails. It provides strength, structure, and resilience to hair strands.

You may ask, what microscopic layers make up the hair?

1. Cuticle – the outermost layer. It is made of overlapping cells that protect the inner layers. It is responsible for the hair’s shine and smoothness and is a barrier against physical and chemical damage.
2. Cortex – the middle layer. It contains keratin and melanin. This layer provides strength and elasticity. This layer determines the texture and curl pattern of the hair.
3. Medulla – the innermost layer. It is sometimes absent in finer hair. It has a more spongy structure. It plays a role in the hair’s structure and flexibility.

The keratin comprises amino acids, primarily cysteine, which form strong disulfide bonds. These bonds are what give hair its strength and shape. Also, hair contains small amounts of lipids, water, and minerals.

What are the characteristics of the hair? Let me take you on a more profound look! Your hair has several characteristics:

1. Color can vary from black, brown, blonde, gray, or white. It is determined by the amount and type of melanin in the hair.
2. Length refers to how long the strands are. It can vary from very short to extremely long. However, it depends on how much it has grown and whether it has been cut.
3. Texture describes the feel and appearance of the hair. It can be fine, medium, or coarse. It also refers to whether the hair is straight, wavy, or curly.
4. Thickness refers to the density of the hair strands on the scalp. You may have thick, full hair, while others may have thin or sparse hair.
5. Shape can be round, oval, or flat, influencing whether the hair is straight, wavy, or curly.
6. Condition describes the health of the hair. Healthy hair is shiny, smooth, and strong, while damaged hair is dry, brittle, or frizzy.
7. Style refers to how the hair is arranged or groomed. It could be natural, braided, tied up, or styled with tools and products.

It is important to note that each characteristic can vary from person to person.

Here is a fun fact for you! Your hair characteristics can change due to genetics, age, and hair care practices.

What kind of cells are in hair?

The protein keratin is produced by specialized cells called keratinocytes. These cells originate in the hair follicle, located in the dermis, the middle layer of the skin.

Here is how it works:

1. Hair follicle and keratinocytes – The hair follicle is a tiny structure in the skin where hair grows. Inside the follicle, keratinocytes multiply and produce keratin, a tough and fibrous protein that gives hair strength and structure.
2. Hair Shaft Formation – As keratinocytes move upward through the follicle, they die and become part of the hair shaft. When the hair emerges from the skin, it is made of dead keratinized cells. This is why the visible part of your hair is not “alive.”
3. Melanocytes – Another type of cell in the hair follicle is the melanocyte. These cells produce melanin, the pigment that gives hair its color. The amount and type of melanin determine whether your hair is black, brown, blonde, or red.

The primary cells in hair are keratinocytes (which produce keratin) and melanocytes (which provide pigment). Once the hair grows out of the follicle, it comprises dead keratinized cells.

If you are uncertain whether hair is a protein or a cell, here is a breakdown!

Hair is primarily made up of a protein called keratin, a fibrous structural protein found in nail and skin. It is responsible for the strength and structure to the hair strand.

Hair itself is not a living cell. The part of the hair you see (the shaft) is made of dead keratinized cells that have been pushed out of the hair follicle. The living part of the hair is in the follicle beneath the skin, where cells divide and grow to form the hair strand. So, while hair is not a cell, it is made of protein and originates from living cells in the follicle.

Is hair an organ or tissue?

Hair is considered a tissue, not an organ. Here’s why:

In biology, an organ is a structure of multiple types of tissues that work together to perform a specific, complex function. For example, the heart is an organ because it contains muscle, connective tissue, and nerve tissue, all working together to pump blood.

On the other hand, a tissue is a group of similar cells that perform a specific function. Hair comprises keratinized cells, specialized cells that produce keratin, a tough protein. These keratinized cells form a structure (the hair shaft) but don’t combine with other tissue types to create a complex organ.

Hair itself is just a single type of tissue. However, the hair follicle, the structure in the skin that produces hair, is more complex. The follicle contains multiple tissue types (epithelial, connective, and sometimes muscle tissue), so it could be considered part of an organ—the skin.

The hair itself is a tissue, not an organ, because it is made of one type of specialized cell and doesn’t have the complexity of an organ.

What part of the hair contains DNA?

Hair is made up of two main parts:

The shaft (the visible part above the skin) and the root (the part below the skin, inside the follicle). The shaft is made of keratin, a protein, and does not contain any DNA because it consists of dead cells. The root, however, is located within the hair follicle under the skin.

This is where living cells are present, and these cells contain DNA. Specifically, the DNA is found in the nucleus of the cells in the root. When hair is pulled out with the root attached, it often contains follicular tissue rich in DNA. This is why hair with the root is used in forensic investigations for DNA analysis.

FUN FACTS!

1. Hair is mainly made of keratin. This is the same protein that makes up your nails and the outer layer of your skin.
2. Hair grows fast. Hair is the second fastest-growing tissue in the human body, after bone marrow. It grows about 0.5 inches (1.25 cm) per month.
3. You have a lot of hair. The average person has about 100,000 to 150,000 hair strands on their scalp. Blondes tend to have the most hair, while redheads have the least.
4. Hair is strong. A single strand of hair can support up to 100 grams of weight. Combining all the hair on your head could support the weight of two elephants!
5. Hair is mostly water. About 25-30% of your hair’s weight is water. This is why it feels heavier when wet.
6. Hair color is determined by melanin. The amount and type of melanin in your hair determine its color. As you age, melanin production decreases, leading to gray or white hair.
7. Hair is dead. The visible part of your hair (the shaft) is made of dead cells. Only the root in the follicle under the skin contains living cells.
8. Hair can “feel” things. While hair itself doesn’t have nerves, the follicles are surrounded by nerve endings. This is why you can feel a light touch or movement on your hair.
9. Hair grows in cycles. Hair growth happens in three phases: anagen (growth phase), catagen (transition phase), and telogen (resting phase). About 85-90% of your hair is in the growth phase at any given time.
10. Hair can reveal your health. Hair can store information about your diet, drug use, and environmental exposure. This is why hair samples are sometimes used in forensic or medical testing.

Hair is more than just an aspect of our looks—it’s a remarkable structure made mainly of keratin, molded by   living   cells,   and shaped by   our   genetics, surroundings, and grooming habits. While the hair we see is dead, its roots are alive, secreting a tissue that mirrors our identity and gives us important clues about our health and way of life.

By learning about hair’s layers, structure, and microscopic characteristics, we appreciate a taken- for-granted aspect of life. So the next time you catch a glimpse of yourself in the mirror, remember—your hair has a tale of biology, toughness, and uniqueness.

As we’ve seen, hair isn’t just a mere styling subject. It’s a fantastic structure composed of keratin, molded by living cells, and affected by our biology, habits, and grooming. From its microscopic layers to its capacity to reflect our well-being, hair is an incredibly compelling testament to how even the most mundane aspects of our body contain monumental design and function.

So the next time life gets too much, remember: there’s worth in the fundamentals. In learning to see and appreciate even   the little things,   such as our   hair,   we find again a   sense of awe and appreciation for ourselves.

References:

Cleveland Clinic. (2022). Integumentary System. Cleveland Clinic; Cleveland Clinic. https://my.clevelandclinic.org/health/body/22827-integumentary-system

Elkins, Z. (n.d.). How does our hair contain DNA? Columbia Daily Tribune.

https://www.columbiatribune.com/story/lifestyle/family/2018/10/09/how-does-our- hair-contain/9605125007/

Kingsley, A. (2022, April 11). The Hair Structure. Https://Www.philipkingsley.co.uk/. https://www.philipkingsley.co.uk/hair-guide/hair-science/the-hair-structure.html

Magtiza, A. (2021, February 19). 2.2 Hair and Scalp Assessment. Opentextbc.ca; BCcampus. https://opentextbc.ca/haircolourforhairstylistslevel2/chapter/consultation/

Miller, C. (2020, September). 10.5 Hair. Pressbooks.pub; Thompson Rivers University. https://jwu.pressbooks.pub/humanbiology/chapter/12-5-hair/

Radhakrishnan, R. (2024, May 28). What Are the Four Types of Hair? MedicineNet. https://www.medicinenet.com/what_are_the_four_types_of_hair/article.htm

Specific Hair Follicular Keratinocyte Cell Types – CZ CELLxGENE CellGuide. (2025). Cellxgene Data Portal. https://cellxgene.cziscience.com/cellguide/CL:2000092

Watson, K. (2020, September 11). Is Hair Made of Dead Skin Cells? Healthline; Healthline Media. https://www.healthline.com/health/is-hair-dead#hair-growth

What Is Hair Made Of? – L’Oréal Paris. (n.d.). L’Oréal Paris.

https://www.lorealparisusa.com/beauty-magazine/hair-care/all-hair-types/what-is-hair- made-of-structure-anatomy

Wikipedia Contributors. (2019, June 3). Hair. Wikipedia; Wikimedia Foundation. https://en.wikipedia.org/wiki/Hair

Written by Danielle Bubole

Edited and Reviewed by Reuben J C. Los Baños, Ph.D.

The Golgi apparatus is the collecting, sorting, and packaging site of your cell. These packaged and sorted materials are then delivered to different sites for daily use. Thus, your Golgi apparatus’ main function is arranging collected cellular materials and putting them inside a vesicle to be delivered and used to different sites.

It’s either delivered to:

• The outside of your cell (through exocytosis)
• Endosomes make it into lysosomes
• Other cytoplasmic components

Exocytosis is the process of getting stuff outside of the cell.

Endocytosis is the process of getting stuff into the cell.

Now that you have a grasp of the overview of your Golgi apparatus’ function, let’s learn its main components.

Similar to your organ system which consists of collaborating organs, your Golgi apparatus also has its own components, these are:

• Cisternae – smooth membrane sac that forms the flat discs with swollen ends of your Golgi apparatus.
• Tubules – short interconnected structures protruding on the sides and also at a part of your Golgi apparatus that faces your cell membrane.
• Vesicles – sacs that develop from your tubules.
• Golgi vacuoles – large rounded sacs produced from a part of the Golgi apparatus that faces your cell membrane. Sometimes, it also acts as a lysosome.
• ERGIC – also called as Endoplasmic Reticulum Golgi Intermediate Compartment helps in the transport between your ER and Golgi apparatus.

Moving on to its networks, your Golgi apparatus is also divided into clusters of cisternae called:

• The convex cis face or the forming face (cis-Golgi Network)
• The concave trans face or the maturing face (trans-Golgi Network)

Forming face is what is near your endoplasmic reticulum and the primary site to receive the materials in the vesicles from your ER.

Maturing face is what is near your cell membrane and the site where the vesicles to be delivered in other sites are pinched out.

You must keep these in mind as we go into its process.

Remember that the proteins and lipids or the materials made by your ER are packaged in the form of vesicles. With the help of ERGIC, these vesicles will fuse with your forming face of your Golgi apparatus and move toward your maturing face. At the maturing face, the vesicle with the sorted and modified materials inside is pinched out to be delivered outside of the cell, fused with endosomes to make lysosomes, and delivered to other cytoplasmic components.

All in all, that is how your Golgi apparatus works. However, to know more let’s dive deeper!

What is the function of the Golgi vesicles?

Golgi vesicles are small sacs that develop from tubules. Your Golgi apparatus’ vesicles help the transport of materials from one place to another. It encloses it, acting like a barrier from other cytoplasmic components.

There are two types of Golgi vesicles, namely:

• smooth vesicles
• coated vesicles

Different types of Golgi vesicles also have specific different functions. Let’s take a look at what these two types have.

Smooth vesicles

• Does not have a protein coat
• Transport materials inside your Golgi apparatus, to the plasma membrane, and other organelles
• Your smooth vesicles include secretory vesicles and other Golgi transport vesicles

Examples of your smooth vesicles are:

• Secretory vesicles (those that release hormones and neurotransmitters)
  • Transport vesicles inside your Golgi apparatus
  • Lipid-containing vesicles
• Their release mechanism can be constitutive (constant release) or regulated (stimulus-dependent release)

Coated Vesicles

• Covered with a proteinaceous coat (COPI, COPII, clathrin)
• Helps in your sorting, packaging, and transport of materials by selecting specific molecules
• Your coated vesicles include COPI, COPII, and clathrin-coated vesicles:
  • COPI-coated vesicles: retrograde transport in Golgi; it helps return proteins that accidentally left the ER.
  • COPII-coated vesicles: ER to Golgi transport
  • Clathrin-coated vesicles: transport materials from your Golgi to the endosome, which also involved in endocytosis
• Your coat assists in the selection of materials and budding of your vesicle. It is also removed before fusing with the target site.

Therefore, your type of vesicle relies on what appearance it has, whether it is coated or not. If it is coated what type of protein coat is present?

What is the role of the Golgi body in secretion?

Golgi body or Golgi apparatus transports modified materials to different sites. It includes delivering materials inside a vesicle outside of the cell. Thus, this is what you can call an example of secretion.

Back to your knowledge of cells, your cells produce proteins. For example, your nerve cell produces neurotransmitters, pituitary cells produce peptide hormones, and beta cells secrete insulin.

What do these have in common? Your secretory vesicles

There are two types of secretion, namely:

• Constitutive secretion – vesicles from the mature face are sent to the cell’s membrane for continued secretion
• Regulated secretion – vesicles containing the materials for secretion remain on the cell’s surface and wait for the signal to be secreted.

Now that you are set with this information, let us look more at its process.

Imagine the pancreatic beta cell, in these beta cells vesicles are filled with your insulin that is then modified and pinched out as a vesicle from the mature face of your Golgi apparatus.

Vesicles containing the same materials will fuse forming larger secretory vesicles. Those vesicles that contain insulin build up in the cell and wait for a glucose signal to enter the cell.

Once the glucose arrives, it will start a complicated process that causes the release. In a sense, it is not freed up because of glucose itself but because of the complicated process caused by the presence of glucose.

The secretory vesicles that contain the materials, insulin, will move to the plasma membrane and release the materials to neighboring blood capillaries. This process along with regulated release is what you call exocytosis.

Your released insulin will now act as a regulator that stimulates others.

In summary, Golgi body forms the vesicle for the materials needed to be secreted outside the cell or transported to different cytoplasmic components.

Where is the Golgi apparatus located?

Your Golgi apparatus is a membrane-bound organelle found in eukaryotic cells. It is located near the endoplasmic reticulum and nucleus.

Essentially, Golgi apparatus works very often with your endoplasmic reticulum. The materials made by your ER are transported via the vesicles to your Golgi body then sorted, modified, and packed to deliver into different sites. This explains why the Golgi apparatus remains close to the endoplasmic reticulum.

Secretory cells, those cells that the major function is to secrete contain many Golgi apparatus, however, no matter how many of them, these are still located in close proximity to your ER.

If you get into detail:

• Convex cis face or the forming face – is located near the ER.
• Medial Section – is located in the middle of the forming face and maturing face.
• Concave trans face or the maturing face – is located far from the ER and much closer to the cell membrane compared to your forming face.

Note: this is not to be confused with the Golgi network. Your Golgi networks are two clusters of cisternae namely the cis-Golgi Network and trans-Golgi Network. While the Convex cis face or the forming face, the Medial Section, and the Concave trans face or the maturing face are the regions.

Cisternae is divided into networks that are composed of regions containing different components such as your cisternae, golgi tubules, golgi vesicles, golgi vacuoles, and ERGIC. In summary, your Golgi apparatus is located near your ER to facilitate efficient transport of materials from your ER to the forming face towards the maturing face through the medial section.

Your network’s location is dependent on its function such as to receive or to secrete vesicles.

What would happen to the life of a cell if there was no Golgi apparatus?

Your cells produce proteins. Nerve cell produces neurotransmitters, pituitary cells produce peptide hormones, and beta cells secrete insulin. These are all products of your Golgi apparatus’ work.

Golgi apparatus collects, sorts, and packages materials to be brought to different sites via vesicles. Many of your proteins are synthesized by ribosomes in the endoplasmic reticulum, these are transported to your forming face and then modified before the vesicle containing these materials is pinched out from the mature face of your Golgi apparatus.

Your vesicles containing the materials modified from your Golgi apparatus move and fuse to larger secretory vesicles containing the same materials. These build up until it is secreted. Your cells’ secretion via Golgi apparatus is very important because it stimulates other molecules, and in turn responds to them, contributing to the overall process of the body.

Aside from getting the materials outside of the cell, vesicles from the mature face are delivered to either the endosomes to form lysosomes and other cytoplasmic components.

Your Golgi apparatus, Endoplasmic reticulum, and endosomes work in harmony. ER produces vesicles containing the materials transported to the Golgi apparatus which is then modified. Your modified materials are delivered outside of the cell for extracellular needs or add up to the cell membrane, and they can be transported to the endosomes to help produce the lysosomes.

Lysosomes are your cells’ site of digestion. It contains digestive enzymes, specifically hydrolytic ones. It breaks down wasted or worn-out cell parts, destroys viruses and bacteria, and ultimately, performs cell death if a cell is beyond repair to eliminate unwanted cells.

Therefore, if your Golgi apparatus is absent in your cell, there will be no means of transportation for secreting materials outside of your cell or exocytosis, no production of lysosomes, and no delivery of needed materials to other cytoplasmic components.

All in all, your cell will eventually DIE!

Who discovered the Golgi apparatus?

Golgi apparatus was discovered by Camillo Golgi. He is an Italian cytologist who discovered Golgi apparatus in a nerve cell of an owl.

Studying the nervous tissue, Camillo established a staining technique. This technique is named reazione nera, which means “black reaction.” In the present, it is known as the Golgi Stain. His way of staining includes fixing the nervous tissue with potassium dichromate and bathing it with silver nitrate.

While studying neurons using his technique, he identified an “internal reticular apparatus” and then later on called the Golgi Apparatus.

Camillos’ finding of this structure was doubted by other scientists but then during the invention of your electron microscope, Golgi Apparatus was confirmed to be real.

His findings not only contributed to scientific innovation but also led many medical developments to emerge, particularly in cell biology, neuroscience, and disease and research.

What are some interesting facts about the Golgi apparatus?

Golgi contains about 1,000 different proteins in mammalian cells, however, only 200 of them have been identified as of now.

Having 1,000 different kinds of protein only suggests that a very small component can do so much such as:

• Glycosylation – helps in protein folding, protects proteins from damage, and enables cell signaling and communication. (Example: The difference in blood types is due to different glycosylation patterns on red blood cells.)
• Processing hormones and neuropeptides – most hormones and neurotransmitters function after it is cut and activated. (Example: Insulin is also processed by your Golgi apparatus, which is important for your blood sugar regulation and preventing diabetes.)
• Transporting and sorting proteins – transports your proteins to specific locations and avoids misplacement that can cause diseases. (Example: Genetic disorders like I-cell or the build-up of waste in the cell will happen if lysosomal enzymes are not sent to lysosomes.)
• Making and modifying lipids – Production of your lipids for cell membranes and signaling molecules. (Example: Your sphingolipids are made by your Golgi apparatus, this is important for brain function and nerve protection.)
• Moving ions and molecules across membranes – supports your cell balance and metabolism for cell survival. (Example: Wilson’s disease can occur if mutations in copper-transporting proteins happen. This is caused by the build-up of copper in the body.)
• Maintaining Golgi structure – it keeps your Golgi apparatus organized so materials can be processed correctly and delivered to where it is needed. (Example: Disruptions of your Golgi apparatus can cause cancer and neurodegenerative diseases.)
• Connecting to the cytoskeleton – helps in cell division, immune response, and nerve function. (Example: Movement of your Golgi apparatus is needed for the release of your immune cells to targeted directions, fighting infections.)

Therefore, your Golgi apparatus is as important as any organelle in your cell.

References

Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2002). Molecular Biology of the Cell (4th ed.). Garland Science. ISBN: 0-8153-3218-1

Darshan classes. (2022, September 8). What would happen to the life of a cell if there was no Golgi apparatus? [Video]. YouTube. https://www.youtube.com/watch?v=VnWC2Co6g3I

Alberts, B., Bray, D., Hopkin, K., Johnson, A. D., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2013). Essential Cell Biology (4th ed.). Garland Science. ISBN: 978-0815344544.

Hua Z, Graham TR. The Golgi Apparatus. In: Madame Curie Bioscience Database [Internet]. Austin (TX): Landes Bioscience; 2000-2013. Available from: https://www.ncbi.nlm.nih.gov/books/NBK6268/

Joao’s Lab. (2023, June 16). Golgi apparatus: structure and function [Video]. YouTube. https://www.youtube.com/watch?v=Jn-1lB5jb6I

LearnCBSE. (2024, August 12). NCERT Solutions for Class 9 Science Chapter 5 The Fundamental Unit of Life. Learn CBSE.

Life Science Resources. (2013, August 24). Golgi Complex: its secretions [Video]. YouTube. https://www.youtube.com/watch?v=0VBuA6XeSGQ

Medicosis Perfectionalis. (2018, October 22). The Golgi Apparatus “the sorter” – Cell Biology and Histology [Video]. YouTube. https://www.youtube.com/watch?v=hQEUFmOPdAs

Ninja Nerd. (2023, February 24). Golgi Apparatus Structure & Function [Video]. YouTube. https://www.youtube.com/watch?v=TPgyv2411Xo

Practically. (2020, December 30). Practically’s concepts – Golgi apparatus – #LearnPractically [Video]. YouTube. https://www.youtube.com/watch?v=iA8hFSHS6Ho

The Editors of Encyclopaedia Britannica. (n.d.). How was the Golgi apparatus discovered? | Britannica. Encyclopedia Britannica. https://www.britannica.com/question/How-was-the-Golgi-apparatus-discovered

Written by Mary Margarethe R. Cuevas

Edited and Reviewed by Reuben J C. Los Baños, Ph.D.

The lysosome plays a crucial role in cellular survival. It acts as the cell’s garbage disposal system. It also breaks down macromolecules and recycles cellular components. They are always perceived as the degradative organelle of the cell.

We all know that cells are the basic building blocks of life. They are the smallest units of life. But, they also carry out all the functions needed to keep organisms alive. Inside the cell, it has even smaller parts that we call as organelles. These organelles all perform different functions for our cells to operate.

One organelle that we all know is the nucleus. It is the one that stores all our genetic information. But, there is also this one tiny organelle that will be the subject in this article. Scientists call it the garbage disposal system of the cell, but it does much more than that.

Recent studies realized that lysosomes take part in other cellular processes. They are also involved in the killing of cellular pathogens. These pathogens are organisms that can grow and reproduce inside a host. Lysosomes are also involved in lysosomal membrane repair.

Damaged lysosomal membrane leads to cytoplasm leakage. When this happens, it needs to be immediately repaired. But, if a cell becomes damaged beyond repair, it will undergo cell death. It repairs itself through self-death, or apoptosis. This mechanism is crucial to not harm the surrounding cells. The lysosome is responsible for this job.

These are only some of the important cell processes that involve the lysosomes. Without them to perform these functions, the effects to our body can be detrimental.

What is the role of lysosomes in health and disease?

Lysosomes play a vital role both in health and disease as the cell’s disposal and recycling system. All the time, we are ingesting bacteria. Yet, we don’t always get sick or infected. Though there may be good bacteria, there are bad ones as well.

One of the many things that kept us healthy from bacterial infections are the lysosomes. Cells will ingest the bacteria and send it into its lysosome for destruction. As of now, we all know about the breakdown and recycling function of lysosome. They are able to do this due to the enzymes present in it.

These enzymes, known as hydrolytic enzymes, break down large molecules into small molecules. Our body needs to break large molecules into smaller molecules to use it. If this breakdown does not occur, it can result in a Lysosomal Storage Disease. This causes the lysosome to lose its function and the “trash” inside it accumulates.

Small molecules can turn to large molecules. This also happens inside the lysosomes. Yet, sometimes they can’t get out of it because the transporters needed for it are missing. Additionally, lysosome functions as sensors. They can tell if a cell is healthy or not or if it is being attacked, and track energy levels.

What is the role of lysosomes in cell death?

When damage occurs to a cell, it undergoes a mechanism called apoptosis. This mechanism is done by the lysosome. It is a crucial step to remove unnecessary and broken cells. These cells may hinder an organism’s growth and development when not removed. What happens is that our cells will receive signals to undergo apoptosis.

The lysosomes will then release their enzymes to the cytosol. Its lysosomal membrane breaks down, allowing the release of cathepsins and other proteases. These released enzymes activate a series of events that will end up killing the cell. We call this process Lysosomal Membrane Permeabilization (LMP).

Moreover, lysosomes are also involved in other forms of regulated cell death. The extent of lysosomal damage determines the type of cell death occurring. If a cell experiences partial damage, it still may undergo apoptosis. Some cells though undergo complete rupture. This results in what we call Necrosis.

How do lysosomes protect themselves from getting degraded by the enzymes present inside them?

We now know that lysosomes contain enzymes with digestive and hydrolytic functions. This time, are we not curious as to how the lysosomes protect themselves from degrading? Lysosomes are able to protect themselves through several mechanisms:

• Membrane protection – The lysosomal membrane itself serves as a protective barrier. A lipid bilayer composes the membrane and can withstand an acidic environment. Inside the lysosome is acidic due to the enzymes inside it. This gives the membrane another function. It keeps on these enzymes inside the membrane.

• Acidic environment – The lysosomal enzymes are also known as acid hydrolases. The acidic conditions inside the lysosome (pH 4.5 – 5.0)  is what activates the enzymes. The cytosol on the other hand is in neutral pH (pH 7.2) which can inactivate the enzymes when released outside.

• Repair mechanisms – When a damage manifests to the lysosomal membrane, the cell can start repairing it. This mechanism will restore the membrane’s integrity and prevent enzyme leakage. The cell does this by recruiting proteins that can help patch or repair any damage.

Can humans survive without lysosomes?

You have now reached this part of the article. By this time, we should have a similar response to this question. Indeed, humans cannot survive without lysosomes. We learned that the lysosome plays a role in important cellular processes.

As the cell’s disposal and recycling system, they facilitate autophagy and endocytosis. Basically, it digests internal and external materials. Examples of these are degrading proteins into amino acids and carbohydrates into simple sugars.

We also discussed how lysosomes play a role in the immune response. It is the one who destroys the invading bacteria and viruses to your body. Phagocytic cells engulf pathogens and enclose them in phagosomes through autophagy. Fused with lysosomes, they form phagolysosomes and then degradation occurs.

Cases where cells can be damaged beyond repair is possible. When this happens, the damaged cell can affect other cells. To avoid this from happening, the cell resorts to initiating self-death. This is done by the lysosomes by releasing their enzymes that break down the cellular components.

What happens when a lysosome dies?

It is now a familiar knowledge that lysosomes face death. Now, we start to wonder what actually happens after they die. Some of it was already discussed in this article. But what happens next? Will they disappear? Do they lie around the cytosol? Can they restore back as lysosomes? We will start answering these questions one at a time.

• Lysosomal membrane permeabilization – What happens first when lysosomes die is their membrane permeabilizes. The enzymatic contents inside such cathepsins will leak into the cytosol.

• Release of hydrolytic enzymes – The released enzymes from the lysosome will begin a series of reactions that will lead to the cell’s death. These reactions can also activate apoptotic pathways that promote apoptosis or necrosis.

•  Cell death pathways – We must know that there are different types of cell death. The type varies depending on the amount of lysosomal leakage. Cell death can be through apoptosis or necrosis. When we say an apoptotic death, the leakage is more regulated. Moreover, necrotic death has extensive and uncontrolled leakage.

• Effect on cellular homeostasis – We learned that the lysosome lumen is acidic. This is due to the hydrolytic enzyme inside it that is active at acidic pH. Once the cytosol receives all these, it may trigger inflammatory responses. These responses  will then contribute to more damage to its surrounding cells.

• Potential recovery – Our cells have mechanisms to recover from moderate LMP. It is through a process called lysophagy. The damaged lysosomes are removed through autophagy. This helps restore cellular function and maintain homeostasis. Note that this can only happen if the damage is not severe.

What is the role of lysosomes in aging?

We will now dive into the last part of this discussion. What does lysosomes have to do with aging?

A scientist in the name of Meng Wang tried to study the secrets tolongevity. Living in a family where longevity seems to run in their blood, she was curious. Wang, together with her team, discovered anti-aging signals in roundworms. These signals came from the lysosome.

In the study, the team discovered that lysosomes trigger a chain reaction of messages. This happens when the lysosome produces a specific fatty acid called dihomo-gamma-linoleic acid. These reactions are then what causes the roundworm’s life span to prolong.

Worms only live for 20 to 25 days. But in their study, the worm’s lifespan increased by 17 days. Additionally, the anti-aging signal that caused this longevity came from a fat tissue. Yet, it was still detected by neurons and tissues elsewhere in the worm.

This study opened doors for other scientists. They wanted to learn more about the other functions the lysosome may have. As for Wang, she didn’t stop there. She believes that there’s still more to discover.

More about it

Just like Meng Wang, there are other scientists out there studying the lysosome. One example would be the study of Shou Wang and her colleagues from Baylor College of Medicine. In the study, they investigated the role of lysosomes in brain function and Alzheimer’s disease.

There is another study from the Tokai National Higher Education and Research System. It is the link between lysosomal and their focal adhesion to cancer cells. Research on cancer treatments has already started a long time ago. The possibility for lysosome as a new therapeutic treatment for cancer contributes to its medical relevance.

Conclusion

Despite their size, lysosomes proved themselves to be important. As I like to appreciate the role of lysosomes, I think of this analogy. Our cell is like a community and lysosomes are the garbage collectors. The garbage collectors only had one main job to do in our community.

But, what we fail to realize are the results of their work. They keep our community clean. We are also far from the risks of diseases. Trashes can contribute to floods if not thrown properly. Instead, they are reused and recycled to other materials. This is exactly what lysosomes do.

Lysosomes protect us from pathogens that cause diseases. They clean our cells by collecting the unused materials in it. Recycling them to materials that can be used by our body. Moreover, it monitors our energy levels. It maintains the cell’s health and responds to stress.

I hope that this article shows you how fascinating it is that we learn more about our body. The more that we learn about it, the more we get to appreciate all of its parts, even the tiny ones.

References:

‌And, E. (2025, January 16). Decoding the link between lysosomal activities and focal adhesions could aid cancer research. Phys.org. https://phys.org/news/2025-01-decoding-link-lysosomal-focal-adhesions.html

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‌Zhu, S., Yao, R., Li, Y., Zhao, P., Ren, C., Du, X., & Yao, Y. (2020). Lysosomal quality control of cell fate: a novel therapeutic target for human diseases. Cell Death & Disease, 11(9). https://doi.org/10.1038/s41419-020-03032-5

Written by Lorraine V. Espina

Edited and Reviewed by Reuben J C. Los Baños, Ph.D.

What is the cytoskeleton and its function? The cytoskeleton is a complex and changing network of protein filaments and tubules. It exists in the cytoplasm of eukaryotic cells and some prokaryotic cells.

It is a key part of the cell’s structure. It supports the cell and helps with many important functions. The scaffold-like structure supports the cell’s shape. It helps with intracellular transport and cell movement, and it also plays a role in cell division.

Three primary types of filaments make up the cytoskeleton.

1. Microfilaments, also called actin filaments, are the thinnest filaments of the cytoskeleton. Subunits of actin protein compose these.

Cells require microfilaments for various activities:

• maintaining cell shape,
• cell movement, and
• muscle contraction.

Actin filaments are dynamic and may polymerize and depolymerize at a rapid pace to allow the cell to change its shape or move.

2. Intermediate Filaments: These filaments are thicker than microfilaments but thinner than microtubules. In a cell, these give the strength and support needed to handle tension and stress.

Intermediate filaments are stiffer and less dynamic as compared to microfilaments and microtubules. Common examples of intermediate filaments are keratin, vimentin, and desmin. These proteins support various types of cells.

3. Microtubules: These are hollow, cylindrical tubes made up of tubulin protein subunits.

Microtubules take part in numerous processes, which include:

• cell division (mitosis and meiosis),
• intracellular transport, and
• the structural integrity of the cell.

They make up the mitotic spindle during cell division. They also act as a “highway” for motor proteins like kinesins and dyneins, which transport cargo inside the cell.

The functions of the cytoskeleton categorize into several key areas:

• Keep Cell Shape: The cytoskeleton gives the cell a strong framework. This support helps the cell resist deformation when under stress.

• Motor proteins like kinesins and dyneins help move things inside the cell. They travel along microtubules, carrying vesicles, organelles, and other cargo.

• Cell Division: The cytoskeleton helps move chromosomes and split daughter cells in mitosis.

• Cell Motility: The cytoskeleton allows for the movement of the entire cell or parts of the cell. This is important in processes such as tissue development, immune responses, and wound healing.

• Signal Transduction: The cytoskeleton connects with signaling molecules. These molecules influence how cells respond to growth factors and other external signals.

The cytoskeleton is a flexible network. It provides support but also changes and adapts to help the cell meet the demands of its environment.

What is the origin of the cytoskeleton?

The origin of the cytoskeleton has a significant connection to the evolution of cellular life. Most scientists think the cytoskeleton formed early in life’s development on Earth. This likely happened around the same time simple prokaryotic cells, like bacteria, appeared.

The cytoskeleton likely started as a set of proteins. These proteins helped the cell keep its shape and supported movement.

Prokaryotic cells have simpler cytoskeletal elements. They include FtsZ, a protein similar to tubulin that helps with cell division. There’s also MreB, an actin-like protein that supports cell structure.

These ancient elements were much simpler than any eukaryotic cell. They served as the building blocks for more complex cellular systems that followed.

As eukaryotic cells evolved, they became more complex and larger. This growth needed better organization inside the cells. The cytoskeleton developed in these cells. It helps with shape and structure. It also allows the cell to divide, move, and transport materials.

Eukaryotic cells have more complex cytoskeletons than prokaryotes. The various types of filaments found in eukaryotes show what prokaryotes lack.

The evolution of a complex cytoskeleton in eukaryotes likely helped multicellularity arise. This change allowed cells to interact, grow, and take on specific tissue roles.

What can damage the cytoskeleton?

The cytoskeleton is an important structure, but it is susceptible to damage or disruption in several forms. Damage to the cytoskeletal component leads to many varied dysfunctional cellular problems.

The most common reasons leading to cytoskeletal damage include:

1. Mechanical Stress: There is mechanical stress due to the physical forces applied in the surrounding environment of a cell. For example, when tissues deform or cells change shape, the cytoskeleton stretches too much. Its parts can break or become disorganized

• Infectious Agents: Pathogens like viruses, bacteria, and parasites often attack the cytoskeleton. They do this to enter host cells or use the host cell for their needs. .

• Oxidative Stress: Reactive oxygen species come from cellular metabolism or environmental damage. They can harm cytoskeletal proteins.

Oxidative damage can harm cytoskeletal structures. This disruption weakens cell function and stability.

• Genetic Mutations: Changes in genes for cytoskeletal proteins can damage the cytoskeleton. This harms its structure and function. Mutations in the dystrophin gene can cause Duchenne muscular dystrophy.

Dystrophin is a protein that links the cytoskeleton to the cell membrane. This condition weakens muscle cells.

• Nutritional Deficiencies: Missing nutrients like vitamin C can weaken the cytoskeleton. Vitamin C is important in the synthesis of collagen, which supports the cytoskeleton in some tissues. A deficiency will make the cytoskeleton fragile and susceptible to damage.

What happens if the cytoskeleton is defective?

Cytoskeleton defects can harm the cell. They may lead to various functional problems. The various outcomes depend on the specific part that is faulty.

Some common effects of the defective cytoskeleton include the following:

• Loss of Cell Shape and Integrity: The cell might lose its shape, become distorted, or not maintain its structural integrity.

Defective actin filaments can cause cells to become rounded. This change affects their normal shape and can hurt their function.

• Impaired Cell Division: The cytoskeleton helps organize and separate chromosomes when cells divide. Defects in microtubules or the mitotic spindle cause aneuploidy. This means cells have an abnormal number of chromosomes.

It leads to cancer, genetic disorders, or cell death.

• Inability to Move or Migrate: Cells need cytoskeletal components to move. If these parts get damaged, cells can’t move well.

For example, immune cells like macrophages may not be able to move toward infection sites, impairing immune responses.

• Impaired tissue function occurs when cytoskeletal proteins in multicellular organisms malfunction. For example, if muscle fibers fail to contract, they become weak. This can lead to diseases like muscular dystrophy.

• Neurological Diseases: Neurons depend on the cytoskeleton for support. It helps move substances along their long axons.

Mutations in proteins such as tau and neurofilaments connect to neurodegenerative diseases. These include Alzheimer’s disease and Parkinson’s disease.

Which cells lack cytoskeleton?

Most cells have a cytoskeleton. It helps keep their shape. It also supports functions and aids in movement and division. However, there are a few exceptions where certain types of cells lack a cytoskeleton or have a very minimal one:

1. Prokaryotic Cells (Bacteria and Archaea): Prokaryotes, including bacteria and archaea, usually do not have the complex cytoskeleton of eukaryotic cells. They do have simpler proteins that help them maintain their shape and facilitate cellular processes such as division.

The FtsZ protein in bacteria acts like tubulin. It helps prokaryotic cells divide by forming a ring structure, ensuring proper cell division. Protein MreB, similar to actin, aids in keeping the shape of prokaryotic cells.

These structures are simpler than microfilaments, microtubules, and intermediate filaments in eukaryotes. Still, they perform similar basic functions.

• Red blood cells (RBCs) classify as eukaryotic. But they lack most of the usual cytoskeleton found in other cells. Mature RBCs lose their nuclei and most organelles as they mature. They have a small cytoskeleton made of spectrin and actin.

This configuration enables them to maintain their balloonlike biconcave shape. Their incompressibility through tiny capillaries is integral to their need for such a shape.

RBCs are different from other cells. They don’t rely on a complex cytoskeleton for structure or function. Their main job is to transport oxygen.

Most eukaryotic cells rely on their cytoskeleton for survival and function. Prokaryotes have simple cytoskeletal structures too, which help them perform essential cellular tasks.

What are the diseases associated with the cytoskeleton?

Cytoskeletons play a key role in keeping cells shaped, dividing, and transporting materials. When disruptions occur, they can lead to many diseases. A few of the more notable diseases related to defects in the cytoskeleton are:

• Cancer: The cytoskeleton guides cell division. When microtubules, actin, or intermediate filaments have issues, it causes uncontrolled growth. This is a key feature of cancer.

Microtubule abnormalities can cause mistakes in chromosome separation, leading to genetic instability. Mutations in actin and vimentin help cancer cells invade nearby tissues. Drugs like taxanes work on microtubules to stop cancer cell division.

• Muscular Dystrophies: Duchenne muscular dystrophy (DMD) happens when there isn’t enough dystrophin. This protein connects actin filaments to the cell membrane. Without it, muscles weaken and waste away.

This causes trouble walking and can lead to losing mobility. Other muscular dystrophies, like limb-girdle muscular dystrophy, involve similar cytoskeletal protein mutations.

• Neurodegenerative Diseases: Alzheimer’s, Parkinson’s, and ALS (Amyotrophic Lateral Sclerosis) affect the cytoskeleton in neurons. In Alzheimer’s, tau proteins disrupt microtubules, causing cell death.

In Parkinson’s, problems with microtubules hinder the movement of key parts. This is especially true in dopamine-producing neurons.

• Ciliopathies: Primary Ciliary Dyskinesia (PCD) and others result from microtubule defects of cilia. The body compromises respiratory and fertility functions.
• Situs inversus is a condition linked to Kartagener’s syndrome. This syndrome is a form of PCD. In situs inversus, the body mirrors all internal organs.
• Epidermolysis Bullosa (EB) is a skin disorder. It causes fragile skin that develops blisters with little effort. This happens due to a mutation in keratin, which helps stabilize cells.
• Hereditary Spastic Paraplegia (HSP) and Charcot-Marie-Tooth Disease (CMT) are neurodegenerative diseases. They happen due to mutations in proteins like microtubules or neurofilaments in neurons. This leads to muscle weakness, sensory loss, and neuron degeneration.

These defects impact how neurons transport signals. This leads to muscle weakness, sensory loss, and progressive degeneration of motor neurons.

What are some interesting facts about the cytoskeleton?

The cytoskeleton is one of the most interesting and dynamic parts within the cell. Its functions provide support, aid movement, and allow communication within and between cells.

No one matches their complexity. The cytoskeleton is unique because it changes all the time. Most cell structures stay the same. The cell builds and breaks down the cytoskeleton in a continuous cycle.

This will enable the cell to change its shape in a short amount of time, move, and adapt to different conditions. When a cell divides, microtubules change shape.

They form the mitotic spindle. The spindle makes sure the two daughter cells get the same number of chromosomes.

The final feature of the cytoskeleton is intracellular transport. Motor proteins, like kinesin and dynein, act like highways. They transport cargo, such as vesicles and organelles, along microtubules or actin filaments.

This transport process is vital for keeping cells balanced by delivering materials to different cell parts.

In neurons, microtubules serve as tracks. They help transport important components to the synapse. This process can break down in neurodegenerative diseases, such as Alzheimer’s and Parkinson’s.

Notable too are the evolutionary implications of the cytoskeleton. Some scientists believe the cytoskeleton helped eukaryotic cells evolve from prokaryotic ancestors.

Prokaryotes had simple cytoskeletal structures from the start. These helped keep their shape and support cell division.

Eukaryotes later developed a more advanced cytoskeletal network. This change allowed them to grow into larger and more complex organisms.

Conclusion

The cytoskeleton is vital for many functions. It helps maintain cell shape and structure. It also plays a key role in movement, division, and transport.

The cytoskeleton not working can lead to serious problems in many diseases. These diseases affect various tissues and organ systems.

One of the most beautiful things about the cytoskeleton is its ability to adapt. It acts as a flexible framework that meets any new cell needs. So, the shape of the cell changes to fit new parts of the cytoplasm.

This helps with movement and cell division, allowing the cell to grow and thrive. The cytoskeleton helps move things inside the cell.

It carries needed substances along its pathways for the cell to use. These functions show how complex the cytoskeleton is.

They also show its role in the evolution of multicellular systems. The cytoskeleton and its related diseases are important for basic science and clinical medicine.

It sheds light on key cellular processes. This also points to possible treatment targets for various diseases.

The cytoskeleton is more than a simple structure. It is dynamic and serves many functions. It is essential for the health and operation of every cell.

References:

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Written by Lawrence Barquilla

Edited and Reviewed by Reuben J C. Los Baños, Ph.D.

The mitochondria’s major role is to generate ATP or adenosine triphosphate. ATP is the cell’s primary energy source and is utilized for reactions. Cellular respiration produces ATP.

The mitochondrion (plural: mitochondria) is an organelle found in all eukaryotic cells. It is popularly known as the cell’s “powerhouse,” and its primary function is to produce energy for the body.

You will learn throughout this article about the powers of the cell’s powerhouse. You will also identify the key roles this organelle plays in the body’s normal physiology.

What is the major goal of cellular respiration?

Cellular respiration is the process of which the major goal is to produce ATP. This process occurs in the mitochondria of cells. Cellular respiration is an integral process. It is where the cells convert nutrients into usable energy in the form of ATP. Thus, the mitochondria sustain life.

The process of cellular respiration is a series of metabolic pathways. In these pathways, glucose and organic molecules break down to produce ATP. This occurs in three main stages as follows.

1. Glycolysis

This involves splitting one molecule of glucose into two molecules of pyruvate. It is the process of splitting a 6-carbon sugar into a 3-carbon sugar. This process generates a net gain of 2 ATP molecules. The method of substrate-level phosphorylation produces these 2 ATP molecules.

Alongside the ATP produced, electron carriers such as NADH molecules are also produced. These will be needed in the later stages of the process. Additionally, this stage occurs in the cytoplasm. Later on, the products will move into the mitochondria for further processing.

• Citric Acid Cycle

The pyruvate molecules from glycolysis now enter the mitochondria. Each of the 2 pyruvate molecules is converted into acetyl-CoA. The products then enter the citric acid cycle afterward. During this stage, ATP is not produced.

However, 2 GTP are produced, which function similarly to that of ATP. GTP stands for guanosine triphosphate. GTP is equal to 1 ATP per 1 GTP molecule produced.

Additionally, the products are electron carriers. These include NADH and FADH2, as well as carbon dioxide, which are waste products. These products will move into the next few steps of the process.

• Oxidative Phosphorylation

This is the final stage in the process of cellular respiration. It takes place in the inner mitochondrial membrane. The electron transport chain makes use of the electrons from the electron carriers.

From the previous steps, NADH and FADH2 serve as the electron carriers of the system. The electron carriers create a proton gradient. This proton gradient allows for the electron transport chain to operate. Additionally, this gradient is what drives the synthesis of ATP.

As electrons are transferred from the carriers, a proton gradient across the inner mitochondrial membrane is created. Once the electrons enter back into the mitochondrial matrix, they pass through the ATP synthase. As they pass through the enzyme, ATP is generated.

This step produces the most ATP among the stages. A total of 28 to 34 ATP molecules are produced.

Which cell in the human body does not have mitochondria?

The erythrocytes, commonly known as the red blood cells, are the only cells in the body that do not contain mitochondria. These erythrocytes not only lack the mitochondria but also lack other cell organelles, one of which is the nucleus.

Red blood cells function primarily to carry oxygen throughout the entire body. Thus, having the adaptation of losing the mitochondria allows for maximized oxygen transport.

By removing this specific organelle, the red blood cells can accommodate more hemoglobin. Once more hemoglobin is accommodated, more oxygen can be transported from the lungs to the tissues to the cells of the body.

Another point to look at is the shape and structure of red blood cells. They have a biconcave shape, which allows for an increased surface area for gas exchange. By removing the mitochondria and other organelles, the red blood cells are able to maximize the space.

Without the mitochondria, you may start to wonder how red blood cells produce energy for their own use. Well, they still have a reliable source of energy through the process of anaerobic respiration.

Anaerobic respiration involves metabolizing glucose through glycolysis. This is to generate ATP without the need for oxygen. Although possible, this is not as efficient as cellular or aerobic respiration. Anaerobic respiration is not as efficient in ATP generation.

Regardless, it enables red blood cells to attain energy. It is important to have an energy source as they carry and transport oxygen through the body.

Overall, having no mitochondria comes to be more beneficial for red blood cells. It is a crucial adaptation that improves their ability to carry oxygen efficiently. This interesting adaptation is what maintains the oxygen concentration at a healthy level.

Which organ contains the most mitochondria?

The heart is the organ that is most abundant in the amount of mitochondria. As the heart is in a continuous state of function, it needs significantly more energy than other organs of the body.

The heart holds the highest number of mitochondria. It amounts to about one-third or 30% of the total cardiac cell volume. The high mitochondrial density enables the heart to generate the needed amount of energy. This energy sustains the rhythmic contractions of the heart.

To help sustain the function of the heart, more ATP is needed. The heart beats about 100,000 times in one day. This activity requires a large amount of energy. As such, the need for more ATP is addressed by having more mitochondria in the cell itself.

The mitochondrial count is also high among other high-energy demanding organs. This includes your liver and skeletal muscles.

The liver is responsible for a lot of functions. It includes detoxification, protein synthesis, and regulation of biochemical reactions. Thus, hepatocytes need more ATP to enable the liver to function efficiently.

The skeletal muscles require a substantial amount of energy for contraction and movement. The more we move our bodies, the more energy is needed. The more active we are, the more mitochondria are required in order to produce more energy.

This all boils down to the fact that as the cells become more active, more energy is needed. In order to keep up with the increased need for energy, more mitochondria are required.

How many mitochondria does a human have?

By a general estimate, humans can have around 1000 mitochondria per cell. As such, the total mitochondria of a human being can be estimated to reach around 100 trillion mitochondria. The sum of all the mitochondria in each possible cell of the human body.

Mitochondrial density varies across different cell types. As you have learned earlier, some cells need more, while some don’t need the mitochondria at all.

By approximation, the diverse activities, functions, and processes a human being undergoes require a ton of energy supplied by the 100 trillion mitochondria everywhere.

What foods repair mitochondria?

Numerous scientists worldwide have recorded mitochondrial damage. As such, researchers discovered that this degradation is reversible. This can be done through food intake that supports and restores mitochondrial function.

1. Antioxidants

Antioxidants are good to combat the presence of free radicals. Free radicals are harmful to the cells and can damage the mitochondria even more. As such, antioxidants are a great way to combat the presence of risky free radicals.

Blueberries and other berries, in general, are packed with antioxidants. Pomegranate seeds have also been found to be high in antioxidants. They are also high in fiber, vitamin C, and potassium.

• B Vitamins

B vitamins work as co-enzymes. These help start up the mitochondrial engines to synthesize energy. These B vitamins are cofactors for many enzymes in the mitochondrial energy metabolism.

For optimal function of the mitochondria, adequate amounts of B vitamins and other vitamins must be observed. Beef is a great and complete source of B vitamins. Additionally, it contains healthy amounts of omega-3 fats.

• Sulfur

Sulfur compounds play a role in mitochondrial dynamics. They also contain antioxidant properties that reduce oxidative stress in the cell.

Sulfur can be sourced from broccoli and broccoli sprouts. They have far higher concentrations of sulfur in broccoli than among other vegetables.

• Fats

Fats in the mitochondria are used as part of a protective membrane. A diet comprised of high-quality fats and oils is essential to ensure a healthy mitochondrion.

Familiar healthy fat sources include olive oil, Butter, and Salmon. Olive oil is rich in phytonutrients that combat free radical damage efficiently. Butter, in healthy moderation, serves as a good source of fat-soluble vitamins.

Fatty fish such as salmon are high in essential omega-3 fatty acids. This helps support mitochondrial function as well as reduce inflammation.

• Magnesium

Magnesium is a mineral that performs numerous functions on a daily basis. The mitochondria depend on magnesium as it is a vital cofactor. Magnesium is involved in glycolysis, cell respiration, and transmembrane transport.

As such, magnesium is in avocados and spinach. Avocados are high in magnesium content as well as their monounsaturated fat. Spinach, along with most common green leafy vegetables, contains high and healthy amounts of magnesium.

It is essential to look at your diet and try to incorporate such examples into your meals. By doing so, you are able to support mitochondrial repair. You are also able to enhance your overall cellular energy turnover. This eventually leads to better health and lifestyle outcomes.

What happens if the mitochondria stop working?

Once the mitochondria stop working, a range of health issues collectively known as mitochondrial dysfunction can occur.

As you may have learned, the mitochondria serve an integral function in sustaining life. Once the mitochondria stop working, the cell will bear the consequences as follows.

1. Energy Deficiency

ATP production now happens at a much slower rate. It results in a significantly lesser turnover.

Aside from cellular respiration, there are also other means of producing ATP in the body. It can occur through beta-oxidation, ketosis, protein catabolism, and anaerobic metabolism. The problem here is that these are not as efficient as the mitochondria in ATP synthesis.

When the body functions continue, the lack of energy will cause a significant imbalance. An imbalance between the production and expenditure of ATP. Thus, an energy deficiency.

• Organ Defects and Dysfunction

Earlier, you have learned that some organs contain more mitochondria than others. This is because of their functions. Some require them to have more mitochondria and generate more energy.

As such, the inhibition of ATP production can lead to severe damage and complications to the heart, skeletal muscles, and kidneys, for instance. The effects can span a range of disorders that overall impair the body’s normal functioning.

• Metabolic Disorders

Metabolic disorders result from mitochondrial dysfunction, and these include mainly diabetes and obesity.

If the body continues to consume the daily food and nutrient intake, the inability to produce the same amount of energy causes an imbalance. This imbalance is between energy production and use leads to a defective metabolism.

Other diseases of a metabolic nature are type 2 diabetes, dyslipidemia, and cardiovascular diseases.

Overall, the mitochondria prove to be the cell’s powerhouse. Not just the cell but the entire body system’s powerhouse. All of the essential functions depend on ATP, and the mitochondria serve to produce as much ATP as needed. Without these important organelles, life would be put to a halt as we deal with its consequences. As such, keeping your body healthy lies at the forefront of ensuring that your organs, tissues organelles, and cells function efficiently.

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