Arterioles

Oxygenated blood is distributed throughout the body by arteries branching into sequentially smaller arteries, arterioles, and capillaries.Arterioles carry blood under lower pressure than arteries, from arteries to capillaries. They control the flow of blood between the two.The muscle layer is relatively thicker than in arteries as it allows constriction of the lumen so it controls the movement of blood to the capillaries.The arteriole wall consists of 3 layers. The elastic layer is relatively thinner than in arteries as blood pressure is lower. Nutrients and waste exchange between the blood and body tissues occurs at the capillary bed.Arterioles contribute to maintaining mean arterial pressure and tissue fluid as they provide some resistance to the flow of blood. By increasing or decreasing their diameter, they can regulate blood flow to specific tissues and organs.