AP BIOLOGY

Detailed explanation-1: -The walls of the alveoli share a membrane with the capillaries. That’s how close they are. This lets oxygen and carbon dioxide diffuse, or move freely, between the respiratory system and the bloodstream. Oxygen molecules attach to red blood cells, which travel back to the heart.

Detailed explanation-2: -The oxygenated blood then leaves the lungs through pulmonary veins. Gas exchange occurs by diffusion across cell membranes. Gas molecules naturally move down a concentration gradient from an area of higher concentration to an area of lower concentration. This is a passive process that requires no energy.

Detailed explanation-3: -Gas Exchange Between Alveolar Spaces and Capillaries The function of the respiratory system is to move two gases: oxygen and carbon dioxide. Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them.

Detailed explanation-4: -Diffusion is the spontaneous movement of gases, without the use of any energy or effort by the body, between the alveoli and the capillaries in the lungs. Perfusion is the process by which the cardiovascular system pumps blood throughout the lungs.

Detailed explanation-5: -Gas exchange occurring between the blood in systemic capillaries and fluid within tissue cells is called internal respiration.