Arterial walls consist of three main layers: the tunica intima, tunica media, and tunica adventitia.
Tunica Intima The innermost layer, the tunica intima, is composed of a single layer of endothelial cells resting on a basement membrane. This layer is in direct contact with the blood flow and plays a key role in regulating vascular tone and permeability.
Tunica Media The middle layer, the tunica media, is primarily made up of smooth muscle cells and elastic fibers. It is the thickest layer and is responsible for maintaining blood pressure and controlling the diameter of the artery through vasoconstriction and vasodilation.
Tunica Adventitia The outermost layer, the tunica adventitia, consists of connective tissue, including collagen and elastin fibers. This layer provides structural support and anchors the artery to surrounding tissues. It also contains nervi vasorum and vasa vasorum, which supply nerves and blood to the arterial wall itself.
