Written By: Capillary, in human physiology, any of the minute blood vessels that form networks throughout the bodily tissues; it is through the capillaries that oxygen, nutrients, and wastes are exchanged between the blood and the tissues.
Structure and function of arteries, capillaries and veins Blood is pumped from the heart in the arteries. It is returned to the heart in the veins. The capillaries connect the two types of blood vessel and molecules are exchanged between the blood and the cells across their walls.
The capillary networks are the ultimate destination of arterial blood from the heart and are the starting point for flow of venous blood back to the heart. Between the smallest arteries, or arterioles, and the capillaries are intermediate vessels called precapillaries, or metarterioles, that, unlike the capillaries,…