PATHOLOGY

Detailed explanation-1: -One cell thick vessels are the blood vessels that join arteries and veins are the tiniest and most abundant blood vessels, called capillaries. They primarily serve the purpose of exchanging materials between the blood and tissue cells.

Detailed explanation-2: -Capillaries contain two layers of cells: Endothelial cells are inside the capillary. They control the flow of fluid, nutrients and gases. Epithelial cells form a protective layer around the endothelial cells.

Detailed explanation-3: -The middle layer, the tunica media, is primarily smooth muscle and is usually the thickest layer. It not only provides support for the vessel but also changes vessel diameter to regulate blood flow and blood pressure.