Capillaries form dense networks between the arteries and the veins, and it is only in the capillary beds that interchange of oxygen, carbon dioxide and nutrients can take place with the cells. 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 …

Capillaries are microvessels and the smallest blood vessels in the body.