Osmosis video - Arteriole, venule and capillary histology

Arterioles, venules, and capillaries are all small blood vessels that play an important role in the cardiovascular system. Each type of vessel has a different structure and function, but they all work together to transport blood throughout the body.

Arterioles are the smallest arteries in the body and they are responsible for regulating blood flow by constricting or dilating in response to various signals. Venules are small veins that collect blood from the capillaries and return it to the larger veins, whereas capillaries form a network between arterioles and venules, and provide a path for nutrients, oxygen, carbon dioxide, and wastes exchange between the bloodstream and tissues.

The histology of each type of vessel is different, but all are lined with a layer of endothelial cells. The smooth muscle cells that make up the walls of arterioles and venules are arranged in layers, while the capillaries only have a single layer of endothelial cells.