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Mural cells are the vascular smooth muscle cells (vSMCs), and pericytes, of the microcirculation. Both types are in close contact with the endothelial cells lining the capillaries , and are important for vascular development and stability.
Vascular smooth muscle cells also play important roles during development, e.g. driving osteocyte differentiation from undifferentiated precursors during osteogenesis. [1] Arteries have a great deal more smooth muscle within their walls than veins, thus their greater wall thickness. This is because they have to carry pumped blood away from the ...
Smooth muscle is grouped into two types: single-unit smooth muscle, also known as visceral smooth muscle, and multiunit smooth muscle. Most smooth muscle is of the single-unit type, and is found in the walls of most internal organs (viscera); and lines blood vessels (except large elastic arteries), the urinary tract , and the digestive tract .
[3] [4] The Bayliss effect in vascular smooth muscles cells is a response to stretch. This is especially relevant in arterioles of the body. When blood pressure is increased in the blood vessels and the blood vessels distend, they react with a constriction; this is the Bayliss effect. Stretch of the muscle membrane opens a stretch-activated ion ...
Pericytes and smooth muscle cells encircle ECs when they are differentiating into arterial or venous arrangements. Surrounding the ECs creates a brace to help stabilize the vessels known as the pericellular basal lamina. It is suggested pericytes and smooth muscle cells come from neural crest cells and the surrounding mesenchyme. [11]
The muscle fiber cells are arranged in 5 to 7 layers of circular and longitudinal smooth muscle with about 50μ in length and contain well-marked, rod-shaped nuclei, which are often slightly curved. Separating the tunica media from the outer tunica externa in larger arteries is the external elastic membrane (also called the external elastic ...
The smooth muscle cells are controlled by vascular endothelium, which releases intravascular signals to control the contracting properties. When a blood vessel is damaged, there is an immediate reflex, initiated by local sympathetic pain receptors , which helps promote vasoconstriction.
However, with respect to vasculature, activation of M 3 on vascular endothelial cells causes increased synthesis of nitric oxide, which diffuses to adjacent vascular smooth muscle cells and causes their relaxation and vasodilation, thereby explaining the paradoxical effect of parasympathomimetics on vascular tone and bronchiolar tone.