What surrounds large blood vessels to produce hemostatic action ?

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Answers:
hemostasis is provided primarily through the arterial smooth muscle layer.
The outermost layer is known as the tunica adventitia or the adventitia, and is composed of connective tissue. Inside this layer is the tunica media, or media, which is made up of smooth muscle cells and elastic tissue. The innermost layer, which is in direct contact with the flow of blood is the tunica intima, commonly called the intima. This layer is made up of mainly endothelial cells. The hollow internal cavity in which the blood flows is called the lumen.
Veins are thin walled and have no muscle layer, but they do have one way valves to present venous reflux and all the blood in the veins from pooling in your feet everytiime you stand up.
Artial muscles are controlled through the autonomic nervous system, unlike the skeletal muscles.

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What surrounds large blood vessels to produce hemostatic action ?

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