capillary
n.n. a tiny blood vessel that connects the smallest arteries to the smallest veins. It is so thin that blood cells can only pass through one at a time.
n. a microscopic blood vessel that connects arterioles to venules, facilitating the exchange of oxygen, nutrients, and waste products between the blood and surrounding tissues.
The capillary network allows oxygen to reach every cell in the body.
In the lungs, oxygen diffuses from the air sacs into the blood through the thin walls of the capillaries.
The dense arrangement of capillaries in the kidneys is essential for the efficient filtration of blood and the reabsorption of vital nutrients back into the circulatory system.
From Latin capillāris (“pertaining to the hair”), from capillus (“the hair, properly of the head”), from caput (“head”).