AP BIOLOGY

Detailed explanation-1: -The respiratory system works directly with the circulatory system to provide oxygen to the body. Oxygen taken in from the respiratory system moves into blood vessels that then circulate oxygen-rich blood to tissues and cells.

Detailed explanation-2: -Oxygen gets into the blood through tiny blood vessels around the alveoli. Red blood cells pick up the oxygen and deliver it to the body’s cells.

Detailed explanation-3: -In external respiration, oxygen diffuses across the respiratory membrane from the alveolus to the capillary, whereas carbon dioxide diffuses out of the capillary into the alveolus.

Detailed explanation-4: -Oxygen is taken up by the alveoli while carbon dioxide is released through their walls. The air that is exhaled contains a higher concentration of carbon dioxide. This gaseous exchange between the alveolar walls and the bloodstream is called external respiration.