Q 16

Choose the correct description of a typical medium-sized vein. A)In these vessels, the thin tunica media is surrounded by a thick tunica externa composed of mostly collagen fibers. B)Ranging from 2 mm to 9 mm in diameter, its thin tunica media consists of one to two layers of smooth muscle cells. C)It has a diameter of approximately 0.4 cm and has more smooth muscle cells and fewer elastic fibers. D)It ranges from 2 mm to 9 mm in diameter, and the relatively thick tunica externa has longitudinal bundles of elastic and collagen fibers. E)It has a diameter up to 2.5 cm, and its tunica media is dominated by elastic fibers rather than smooth muscle cells.

Multiple Choice