artery

An artery is a blood vessel that carries blood away from the heart. In the systemic circulation, arteries typically transport oxygen-rich blood, while the pulmonary arteries carry oxygen-poor blood from the heart to the lungs. Arteries work in tandem with veins and capillaries to form the circulatory system.

Artery walls are structured in three layers: the tunica intima (inner endothelial lining), the tunica media (middle layer of smooth muscle and elastic fibers), and the tunica externa or adventitia (outer connective tissue). Elastic arteries have abundant elastic fibers to dampen the heart's pulse; muscular arteries contain more smooth muscle to regulate blood flow and pressure.

Arteries maintain blood pressure and distribute cardiac output by contracting or dilating in response to neural, hormonal, and local factors. The aorta and major branches conduct blood away from the heart, while smaller arteries and arterioles act as resistance vessels that control flow to specific tissues.

Common categories include large elastic arteries (e.g., aorta, pulmonary trunk), muscular arteries (e.g., femoral, carotid), and arterioles that feed capillary beds. The arterial system forms part of both the systemic and pulmonary circuits.

Clinical notes: Arterial disease includes atherosclerosis, aneurysm, and hypertension, which can affect blood supply and pressure. Blockage or rupture of arteries can cause stroke or organ ischemia. Understanding arterial anatomy and function is central to cardiovascular physiology and medicine.