ANATOMY

Detailed explanation-1: -A pulmonary alveolus (plural: alveoli, from Latin alveolus, “little cavity"), also known as an air sac or air space, is one of millions of hollow, distensible cup-shaped cavities in the lungs where pulmonary gas exchange takes place.

Detailed explanation-2: -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-3: -Your bronchioles are some of the smallest airways in your lungs. Inhaled air passes through tiny ducts from the bronchioles into elastic air sacs (alveoli). The alveoli are surrounded by the alveolar-capillary membrane, which normally prevents liquid in the capillaries from entering the air sacs.

Detailed explanation-4: -In your lungs, the main airways (bronchi) branch off into smaller and smaller passageways-the smallest, called bronchioles, lead to tiny air sacs (alveoli).