Vascular system

The **vascular system** refers to the entire network of blood vessels—including arteries, veins, and capillaries—that circulates blood throughout the body. It is often used interchangeably with "circulatory system," which also includes the heart and sometimes lymphatic vessels. The primary functions are to transport oxygenated blood from the lungs to tissues via arteries, return deoxygenated blood via veins, distribute nutrients and hormones, remove metabolic wastes such as carbon dioxide and urea, support immune surveillance by trafficking immune cells through tissues, and help maintain physiological homeostasis including temperature regulation and pH balance. The health of this network is central to cardiovascular health; dysfunction leads to major diseases such as hypertension and atherosclerosis. The term **"Vascular system"** does *not* refer to a single molecule or receptor but rather an organ-level anatomical structure composed of many different cell types and molecular targets. It cannot be considered a therapeutic target in itself; instead, individual molecules within it—such as receptors on endothelial cells or smooth muscle cells—are valid drug targets. Therefore this entry should be flagged as incorrect for use in structured drug-target databases.

Other names

Circulatory systemCardiovascular system (sometimes used interchangeably, but not always identical)Blood vessel systemVascular tree