HELPPPPPPP!!
Capillaries do not have a tunica media layer. This implies which of the following about capillaries? Capillaries cannot close their valves. Capillaries cannot dilate or contract. Capillaries do not have an outer layer of connective tissue. Capillaries do not contain an inner layer of endothelial tissue.
Arteries and arterioles (small arteries) have muscular walls. They're the main blood vessels involved in vasoconstriction. ... Capillaries are tiny, thin-walled blood vessels that can't constrict.
