Because it is an involuntaru muscle contraction
endothelium
The three layers of an artery are Endothelium, smooth muscle, and connective tissue.
Yes, endothelium does provide a smooth lining on all hollow organs within the cardiovascular system, such as blood vessels, heart chambers, and lymphatic vessels. This lining helps facilitate smooth blood flow and prevents excessive clotting or adhesion of blood cells.
the endothelium is the inner most linning of the artery vessel. Or better known as the Intima..... The tunica intima, the innermost layer, consists of an inner surface of smooth endothelium covered by a surface of elastic tissues
The endocardium is the layer of the heart wall that is made up of endothelium overlying connective tissue. This layer lines the interior of the heart chambers and valves, providing a smooth surface for blood flow.
Simple squamous epithelium
Capillary walls consists of a single layer of flat endothelium
The Vasa Vasorum supply the wall of the large arteries This method to feed the smooth muscle is necessary as the endothelium covering the lumen doesn't permit the ready diffusion of nutrients from the lumen.
Simple squamous. Just like the endothelium & mesothelium.
Endothelium
A single thin layer of endothelium is called a monolayer.
Gabor M. Rubanyi has written: 'The endothelium in clinical practice' -- subject(s): Pathophysiology, Physiopathology, Prostacyclin, Endothelium, Endothelins, Therapy, Thromboxanes, Vascular endothelium, Physiology, Heart Diseases