AP BIOLOGY

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: -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-3: -In your lungs, the main airways (bronchi) branch off into smaller and smaller passageways-the smallest, called bronchioles, lead to tiny air sacs (alveoli).

Detailed explanation-4: -The respiratory bronchioles have single alveoli off their walls. The epithelium is ciliated cuboidal epithelium and contains some secretory cells called clara cells. The respiratory bronchioles lead into alveolar ducts, (which are surrounded by smooth muscle, elastin and collagen), which lead into the alveolar sacs.

Detailed explanation-5: -Lungs contain many small, elastic air sacs called alveoli. With each breath, these air sacs take in oxygen and release carbon dioxide. Typically, this exchange of gases occurs without problems. But sometimes, the alveoli fill with fluid instead of air.