Arteries

Arteries are blood vessels that transport blood away from the heart. In the systemic circulation they typically carry oxygenated blood, whereas the pulmonary arteries carry deoxygenated blood from the heart to the lungs. Arteries branch into smaller arterioles that feed capillary beds where gas and nutrient exchange occur.

Arterial walls have three layers: the tunica intima, tunica media, and tunica adventitia. The media contains smooth muscle and elastic fibers that provide strength and the ability to stretch. Elastic arteries near the heart, such as the aorta, store energy during heart contraction and help propel blood forward; muscular arteries distribute blood to specific regions of the body. Arterioles, the smallest arteries, regulate blood flow and systemic vascular resistance, contributing to blood pressure control. Arteries are thick-walled to withstand high pressures and maintain pulse waves.

Blood flow through arteries is regulated by the autonomic nervous system and local factors, including oxygen, carbon dioxide, and pH levels. Vasoconstriction and vasodilation adjust tissue perfusion in response to metabolic needs, temperature, and hormonal signals. Arterial blood delivers oxygen and nutrients to tissues and participates in signaling and temperature regulation.

Clinical relevance includes diseases such as atherosclerosis, aneurysm, and peripheral artery disease, which can impede blood flow and threaten organ function. Blood pressure is commonly measured via arterial values, and abnormalities can indicate cardiovascular risk. Developmentally, arteries form from mesodermal tissue and are lined by endothelial cells that form the lumen.