The smallest blood vessels. They permeate the tissues, serving as microscopic extensions of arterioles and venules; through their semipermeable walls, fluids, nutrients, and waste gases are exchanged between the blood and the tissues.

tiny hair-like blood vessels, some of which carry nutrient to the hair growth matrix.

The small blood vessels at which gas and nutrient exchange occurs.

microscopic blood vessels that link arteries with the veins.