AP BIOLOGY

Detailed explanation-1: -During gas exchange oxygen moves from the lungs to the bloodstream. At the same time carbon dioxide passes from the blood to the lungs. This happens in the lungs between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli.

Detailed explanation-2: -The exchange of gases (oxygen and carbon dioxide) occurs between the alveoli and blood capillaries by simple diffusion.

Detailed explanation-3: -1. The exchange of gases between blood capillaries and the cell is called internal respiration. 2. The exchange of gases between the alveoli and the blood capillaries is called external respiration.

Detailed explanation-4: -Gas exchange in the alveoli occurs primarily by diffusion. Traveling from the alveoli to capillary blood, gases must pass through alveolar surfactant, alveolar epithelium, basement membrane, and capillary endothelium.