Alveoli: The Importance of Efficient Gas Exchange in the Lungs

Alveoli

tiny sacs of lung tissue specialized for the movement of gases between air and blood

Alveoli are tiny air sacs in the lungs, where the exchange of oxygen and carbon dioxide takes place. They are located at the end of the respiratory bronchioles and are surrounded by capillaries. The alveoli increase the surface area of the lungs, allowing for more efficient gas exchange between the air and the blood.

During inhalation, air enters the alveoli through the bronchioles and oxygen moves from the air into the bloodstream through the walls of the alveoli. At the same time, carbon dioxide from the blood diffuses into the alveoli, ready to be exhaled during the next breath out.

The alveoli are surrounded by a thin layer of fluid, which helps to keep them moist and to prevent them from collapsing during exhalation. They also contain specialized cells called alveolar macrophages, which help protect the lungs from infection and foreign particles by engulfing and removing them.

Various lung diseases can affect the alveoli, such as emphysema, where the walls of the alveoli break down, reducing the surface area and decreasing the efficiency of gas exchange. Other conditions that can affect alveoli include pneumonia and lung cancer.

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