Final answer:
Arterioles have approximately one or two smooth muscle layers in their tunica media and a very thin tunica externa composed predominately of connective tissue.
Step-by-step explanation:
Arterioles are very small arteries that conduct blood to capillaries. Answering your question, arterioles have about one or two layers of smooth muscles in their walls, which constitutes the tunica media layer. Additionally, these vessels have a very thin layer of the tunica externa, which is primarily made up of connective tissue. Unlike larger arteries which may show distinct many-layered tunica externa, in arterioles, this layer is minimally present and helps to anchor the vessels in place without contributing significantly to their structural rigidity.