What is the largest cell in the human body?

Written by Alexis Marian Balisbis

There are 100 trillion cells or more in the human body. These make up tissues, tissues make up organs, and organs make up the organ system. The various functions performed by cells lead to their different shapes and sizes. The female ovum or egg cell is the largest cell in the human body.

Its size is about 120 micrometers (0.0047 in) in diameter and 20 times the size of male sperm, making it visible to the naked eye without the aid of a magnification device. The female ovum is the reproductive cell in the female body. It needs to gather enough nutrients to support a growing embryo after fertilization.

There are approximately 1 million eggs at birth. Moreover, by the time of puberty or menstruation, only 300,000 eggs remain. Usually, females ovulate one egg per month.

What is the smallest cell in the human body?

A cell is the smallest, basic unit of life that controls all the processes of life. Most scientists suggest that the smallest cell in the human body for volume is the male sperm. The reproductive cell of males is the sperm.

A bit smaller than your red blood cell, the sperm head is about 4 micrometers in length and a tail 50 micrometers long. A fertile man may produce between 40 million and 1800 million sperms in total. It will only survive in warm environments; thus, it dies outside the body or when ejaculated.

Which blood cell is smallest in size?

A blood cell is also known as a hematopoietic cell, hemocyte, or hematocyte. The three main types of hemocytes include red blood cell or erythrocyte, white blood cell or leukocyte, and platelet or thrombocyte. The smallest hemocyte in size is the platelets or thrombocytes.

Platelets are minute discs 1 to 4 micrometers in diameter, only about 20% of the diameter of erythrocytes. 150,000 – 350,000 per microliter of blood is the average platelet count. But, they are miniature, so they make up a tiny fraction of the volume. They play a significant role in the repair and regeneration of connective tissue.

  • Production:

The production or formation of platelets occurs in the bone marrow from megakaryocytes or the “giant” cell, which are giant hematopoietic cells in the marrow. The thrombopoietin or TPO, a dominant hormone controlling megakaryocyte development, regulates the production.

Megakaryocyte develops into a giant cell that releases over 1,000 platelets per megakaryocyte due to fragmentation. They break up into the minute platelets either in the bone marrow or soon after entering the blood, especially as they squeeze through capillaries.

  • Structure:

Platelets are the smallest of the circulating fragments of cells, so they are not actual cells. Their average lifespan is about 5 to 9 days only. The shape of platelets, usually plate-like, may change when a break in the blood vessel stimulates them.

When there is a break in the vessel, they become round and extend long filaments. They look like octopuses with long tentacles reaching out to contact the broken vessel wall or other platelets. Then, platelets form a plug to seal the damaged vessel with the long filaments.

Platelets also contain many structures that are necessary to stop bleeding, such as proteins and granules. Proteins on the surface allow them to stick to breaks in the vessel wall and each other. Like muscle protein, they also allow them to change shape when sticky. Granules secrete other proteins that create a firm plug to seal vessel breaks.

  • Function:

Platelets are being pushed out from the center of flowing red fluid to the vessel wall because they are the lightest. They pass along the surface of the vessel lined by cells called the endothelium. Endothelium prevents anything from sticking to it.

The platelets react first to injury. When there is a wound or bruise and a broken endothelial layer, this causes exposure of the tough fibers surrounding a vessel to the liquid flowing blood. The tough fibers attract platelets like a magnet, which stimulates the shape change. They clump onto the fibers, forming blood clots or the initial seal to prevent bleeding.

  • Disorders: (You can explore more conditions but the ones mentioned are some of them)

Thrombocytopenia, a term derived from an old name for platelets, “thrombocytes,” is a disorder with low platelet counts. The cause can be due to the failure of the bone marrow to produce the standard number of platelets. Increased platelet destruction may also happen once production finishes and when releasing it into the circulation.

Thrombocythemia is a disorder in which your bone marrow makes too many platelets. Some symptoms may include bleeding, headache, bruises, and bloody stools.

Which blood cell is known as a scavenger?

White blood cells or leukocytes are the fewest of the hemocytes. There are only 5,000 to 10,000 leukocytes per microliter or about 1% of your blood. The several types of leukocytes all connect to immunity and fighting infection. The hemocyte called macrophages, also known as natural scavengers, is a type of leukocyte.

Macrophages, also called granulocytes, are cells in the immune system that belong to the so-called scavenger cells or the phagocyte family. They live in almost all body tissues, such as the liver, brain, small intestine, and skin. They destroy bacteria, stimulate other immune system cells’ action, and remove dead cells.

They are also made in the bone marrow and protect the body against infection. Granulocytes have granules in their cytoplasm. The three classes or subdivisions of Macrophages are:

  • Neutrophil

Neutrophils are the most common type and the most many, making up about 50% to 70% of all leukocytes and have a lifespan of 7 hours. The granules are very tiny and light, so they are challenging to see. They are the first line of protection when infection strikes to kill and digest bacteria and fungi.

  • Eosinophil

These are less common, making up less than 5% of leukocytes and a lifespan of 8 to 12 days. They damage the cells that make up the cuticle or body wall of larger parasites and cancer cells. The large granules contain digestive enzymes that are effective against parasitic worms in their larval form.

  • Basophil

Basophils are the least many and rarely seen, making up less than 1% of all leukocytes and a lifespan of a few hours to a few days. They release heparin which is a substance that inhibits blood clotting, histamine, and other substances that have essential roles in some allergic reactions to help control the immune response or the inflammatory response.

What is the largest blood cell?

The other type of white blood cell is the Agranulocytes that have no distinct granules in their cytoplasm. Examples are lymphocytes and monocytes. The largest blood cell is the monocyte, a leukocyte averaging 15 to 18 micrometers in diameter and making up about 7% of the leukocytes.

In the cytoplasm, large numbers of granules often appear to be more in number near the plasma membrane. The nucleus is big, kidney bean-shaped, and tends to have indenting or folding. Monocytes enter areas of inflamed tissue later than the granulocytes or macrophages.

 Monocytes are capable of motion and are phagocytic (engulfing) cells. They can ingest infectious agents and other large particles. They may help break down bacteria, but they cannot replace the function of neutrophils in the removal and destruction of bacteria.

Production in the bone marrow takes place, then they leave and circulate in the blood. After a few hours, the monocytes enter the tissues, where they develop or mature into macrophages. They have a life span of 3 days which is longer than the life span of many white blood cells.

The other type of agranular leukocyte is the lymphocytes, a part of the immune response to foreign substances in the body. They make up about 28% – 42% of the white cells of the blood. These are much smaller than the three granulocytes. The nucleus is enormous for the size of the cell.

Many lymphocytes are in the spleen, lymph nodes, tonsils, thymus, and lymphoid tissue of the gastrointestinal tract. The T-lymphocytes act against tumor cells and virus-infected cells, while the B-lymphocytes produce antibodies against possible harmful invaders. Both of these are memory cells that may live for many years.

What blood cells carry oxygen?

Blood is the life-sustaining fluid that circulates through the entire body. It also carries nutrients to the body tissues. The life-sustaining cells that transport oxygen all over the body are the red blood cells or erythrocytes. These are the most many, about 5,000,000 per microliter, making about 40% of your total blood volume.

  • Production:

The hormone erythropoietin or EPO manages the production of erythrocytes, which occurs in the bone marrow. With small amounts made by the liver, the kidneys are the leading site for EPO production in response to decreased oxygen delivery, such as anemia and hypoxia or increased levels of androgen hormones.

  • Structure:

Disks that are a bit flattened with an indented center or round, biconcave discs are usually the shape of erythrocytes. The microscopic view looks like an orange or red tire with a thin, almost transparent center. They live for about 120 days or four months. Your body makes new erythrocytes to replace the dead or lost ones.

  • Function:

The hemoglobin in erythrocytes is a protein that carries oxygen. When hemoglobin picks up oxygen in your lungs, the life-sustaining fluid gets its bright red color. The hemoglobin releases oxygen to the different parts of the body as it travels. Erythrocytes also bring carbon dioxide to the lungs for you to exhale, removing it from your body.

  • Illness: (Mentioned below is only one condition, but you can search other types of anemia)

Some causes of these illnesses are diseases, a lack of iron or vitamins in your diet, or inherited from family.

Anemia is a disease in which too few erythrocytes carry enough oxygen all over the body. Pale skin, feeling cold, tiredness, and fast heart rate are some symptoms of anemia. In severe cases, it may cause heart failure. Children with anemia develop slower than other children.

There are many types of anemia, including the most common, iron deficiency anemia. Your body would not make enough hemocytes if you did not have enough iron in your body. Causes may include sudden blood loss, inability to absorb enough iron from food, a low-iron diet, and ongoing chronic fluid loss such as from heavy menstrual periods.

What vitamin helps the body make red blood cells?

The body needs enough erythrocytes to provide oxygen to body tissues. Foods rich in iron and vitamins can aid in maintaining healthy erythrocytes. The vitamin that helps the body erythrocytes is Vitamin B12.

You can get vitamin B12 from eating meat, cheese, eggs, milk, and cereal – usually absorbed by your digestive systems, such as the stomach and intestines.  Supplements containing B12 along with other B vitamins or folate are also available.

Some factors that make it difficult for your soma to absorb enough vitamin B12 include:

  • Poor nutrition during pregnancy
  • Poor diet in infants
  • Eating a strict vegetarian diet
  • Alcohol use
  • Surgery that removes particular parts of the stomach or small intestine, such as some weight-loss surgeries
  • Pernicious anemia happens when the body destroys cells that make intrinsic factor, a protein produced by specialized cells that line the stomach wall.

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https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentID=35&ContentTypeID=160

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https://www2.nau.edu/~fpm/immunology/blood.html

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from https://www.redcrossblood.org/donate-blood/dlp/red-blood-cells.html#:~:text=Red%20blood%20cells%20carry%20oxygen,our%20lungs%20to%20be%20exhaled.

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