How does the respiratory system work?

The respiratory system is responsible for bringing oxygen into the body and removing carbon dioxide. The process begins with inhalation, during which the diaphragm and intercostal muscles contract, causing the chest cavity to expand and air to be drawn into the lungs through the trachea. The trachea branches into the bronchi, which further divide into smaller bronchioles. At the end of the bronchioles are tiny air sacs called alveoli, where gas exchange occurs. Oxygen from the inhaled air diffuses through the walls of the alveoli and into the surrounding blood vessels, where it binds to hemoglobin in red blood cells for transport throughout the body. Meanwhile, carbon dioxide, a waste product of metabolism, diffuses from the blood into the alveoli to be exhaled.

The respiratory system also plays a role in regulating the body's pH balance. Carbon dioxide can combine with water in the blood to form carbonic acid, which can alter the pH of the body's fluids. To maintain a proper pH balance, the respiratory system can adjust the rate and depth of breathing to increase or decrease the amount of carbon dioxide exhaled.