Tunica intima

The Tunica intima (pronounced: too-ni-ka in-ti-ma) is the innermost layer of an artery or vein. It is made up of one layer of endothelial cells and is supported by an internal elastic lamina.

Etymology

The term "Tunica intima" is derived from Latin, where "tunica" means "coat" or "layer", and "intima" means "innermost".

Structure

The Tunica intima is composed of a single layer of simple squamous endothelial cells that is in direct contact with the blood flowing through the artery or vein. These cells are supported by a layer of connective tissue, known as the subendothelial layer, which contains a network of collagen fibers. The internal elastic lamina, a layer of elastic fibers, separates the tunica intima from the next layer, the tunica media.

Function

The main function of the tunica intima is to provide a smooth surface for the flow of blood, reducing friction and preventing blood clot formation. The endothelial cells that make up the tunica intima also play a crucial role in vasodilation and vasoconstriction, the processes that control blood flow and blood pressure.

Related Terms

Tunica media: The middle layer of an artery or vein, composed mainly of smooth muscle cells and elastic fibers.
Tunica adventitia: The outermost layer of an artery or vein, composed mainly of connective tissue.
Endothelial cells: The cells that line the interior surface of blood vessels.
Vasodilation: The widening of blood vessels, which decreases blood pressure.
Vasoconstriction: The narrowing of blood vessels, which increases blood pressure.