Blood vessels have a middle layer of what kind of muscle?
1 Answer
Feb 15, 2016
Smooth Muscle
Explanation:
Blood vessels (both artery and vein) have three layers (tunics) in it's wall :
- Tunica intima
- Tunica media
- Tunica adventitia
Following diagram shows the layers of the wall of an artery :
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Tunica Intima consists of endothelium, which is a single layer of squamous epithelium resting on a basement membrane.
Tunica media or middle layer is composed of smooth muscle and elastic fibers.
Tunica adventitia consists of fibroblasts and collagen fibers.
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In case of veins, the same three tunics compose the wall, with the difference in thickness and valves. Here is a diagram for comparison between arterial and venous wall : see both of them have smooth muscle in middle layer.
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