Descending thoracic aorta
The aorta is an artery that conveys oxygenated blood from the heart to other parts of the body. It is one of the largest arteries in the body. The aorta gives off several paired branches as it descends. In descending order, these include the
Mesenteric arteries
The term mesenteric artery is also used to describe smaller branches of these vessels which, particularly in smaller animals, provide a significant source of vascular resistance. These branches have a dense innervation by sympathetic nerves, allowing the brain to control their diameter and hence the resistance to blood flow to the gut. This is of particular importance when blood flow is required elsewhere, such as in exercise or shock, where a large proportion of the blood is required to supply the needs of skeletal muscle; by constricting the smaller mesenteric vessels, the resistance of blood flow to the gut increases, and hence blood flows more readily to other organs.