ANATOMY

Detailed explanation-1: -Tiny air sacs at the end of the bronchioles (tiny branches of air tubes in the lungs). The alveoli are where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out.

Detailed explanation-2: -The walls of the alveoli share a membrane with the capillaries. That’s how close they are. This lets oxygen and carbon dioxide diffuse, or move freely, between the respiratory system and the bloodstream. Oxygen molecules attach to red blood cells, which travel back to the heart.

Detailed explanation-3: -Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.

Detailed explanation-4: -In six adult human lungs, the mean alveolar number was 480 million (range: 274-790 million; coefficient of variation: 37%). Alveolar number was closely related to total lung volume, with larger lungs having considerably more alveoli.

Detailed explanation-5: -The word “alveolus” comes from the Latin word for “little cavity” while the term “alveolar sacs” is derived from the same word and is used to refer to the pouch where the alveoli are located.