Question

From superficial to deep, the layers of the blood vessel wall include the: Which of the following correctly describes the role of the smooth muscle cells in the blood vessel wall? They play an important role in determining the amount of blood flowing to a tissue (tissue perfusion). They play an important role in blood pressure. They control the diameter of the blood vessel. All of the above. None of the above.

Answer 1

Tunica externa, Tunical media, Tunica intima (interna). D all of the above. The increased thickness of the tunica media in thick-walled vessel comes from an increase in the amount of smooth muscle mainly as a tissue useful for contraction like in vasoconstriction. However, smooth muscle in the walls of vessels can also be thought of different. Since smooth muscle contains contractile elements that hold its cells at certain 1 length, when it is not doing an active contraction and shortening, it tends to maintain its length so, smooth muscle will not stretch out too much, so smooth muscle provides an elastic function. Taken all together, the tunical media can provide strength, elasiticity, and contractile abilities to the blood vessel wall.