capillaries

Definition of capillary

capillary

(KA-pih-layr-ee)
The smallest type of blood vessel. A capillary connects an arteriole (small artery) to a venule (small vein) to form a network of blood vessels in almost all parts of the body. The wall of a capillary is thin and leaky, and capillaries are involved in the exchange of fluids and gases between tissues and the blood.

Source: NCI Dictionary of Cancer Terms