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: -Alveoli are wrapped in tiny blood vessels called capillaries. The air you breathe in fills these air sacs with oxygen-rich air. This is where the exchange of gases occurs.

Detailed explanation-3: -Pathway of air: nasal cavities (or oral cavity) > pharynx > trachea > primary bronchi (right & left) > secondary bronchi > tertiary bronchi > bronchioles > alveoli (site of gas exchange)

Detailed explanation-4: -Gas exchange occurs in the alveolar ducts and alveoli. The former are extensions of the bronchioles and can form several generations, each of which has numerous alveoli in its walls. The alveolar structure of the lung results in a large surface area for gas exchange.