The respiratory system is essential for delivering oxygen to the body and expelling carbon dioxide, both of which are critical for cellular function and overall health. Air enters through the nose, where it is filtered, warmed, and humidified, before traveling down the throat (pharynx) and voice box (larynx). From there, air moves through the trachea, or windpipe, which divides into two bronchi, one leading to each lung. Inside the lungs, the bronchi further divide into smaller bronchioles, ending in tiny air sacs called alveoli. The alveoli are surrounded by capillaries, allowing oxygen to diffuse into the blood while carbon dioxide from the blood diffuses out to be exhaled.

Breathing is controlled by the diaphragm, a muscle that contracts and relaxes to change the volume of the chest cavity. This process allows inhalation and exhalation to occur. Oxygen absorbed into the blood binds to hemoglobin in red blood cells, which carry it to the body’s tissues. Conversely, carbon dioxide—a waste product from cellular metabolism—travels back to the lungs to be released. Disorders of the respiratory system, such as asthma, bronchitis, or chronic obstructive pulmonary disease (COPD), can interfere with this essential gas exchange, impacting the body’s oxygen supply and affecting health.