AP BIOLOGY

Detailed explanation-1: -The capillaries have very thin walls, and through them, nutrients and oxygen are delivered to the cells. Waste products are brought into the capillaries. Capillaries then lead into small veins. Small veins lead to larger and larger veins as the blood approaches the heart.

Detailed explanation-2: -Capillaries are narrow-diameter tubes that can fit single red blood cells and are the sites for the exchange of nutrients, waste, and oxygen with tissues at the cellular level. Fluid also leaks from the blood into the interstitial space from the capillaries.

Detailed explanation-3: -As blood moves through the capillaries, the oxygen and other nutrients move out into the cells. Then waste matter from the cells goes into the capillaries. As the blood leaves the capillaries, it moves through the veins. Veins merge into larger tubes to carry the blood back to the heart.

Detailed explanation-4: -Capillaries connect arterioles to venules. They allow the exchange of nutrients and wastes between the blood and the tissue cells, together with the interstitital fluid. This exchange occurs by passive diffusion and by pinocytosis which means ‘cell drinking’. Pinocytosis is used for proteins, and some lipids.

Detailed explanation-5: -Diffusion transports fluids, gases, nutrients, and wastes between the blood and body tissues through capillaries. Fluid travels from the vessel to the bodily tissue as a result of this process. The blood pressure in the vessel equals the osmotic pressure of the blood in the vessel in the center of the capillary bed.