Final answer:
Muscular arteries, also known as distributing arteries, are medium-sized vessels with abundant smooth muscle that distribute blood to body organs and tissues.
Step-by-step explanation:
The medium-sized arteries referred to in your question are known as muscular arteries. These arteries are characterized by having abundant smooth muscle in their tunica media, which allows them to regulate blood flow by constricting or dilating. As their name implies, muscular arteries, also called distributing arteries, are responsible for branching out and distributing blood to various organs and tissues throughout the body. They play a critical role in the vascular system by transitioning from the larger elastic arteries to smaller vessels known as arterioles, which lead to the capillary networks providing oxygen and nutrients at the tissue level.