Aorta

The aorta   is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it bifurcates into two smaller arteries (the common iliacs). The aorta distributes oxygenated blood to all parts of the body through the systemic circulation. 

Artery: Aorta

The course of the aorta

The aorta is usually divided into five segments/sections

• Ascending aorta—the section between the heart and the arch of aorta
• Arch of aorta—the peak part that looks somewhat like an inverted "U"
• Descending aorta—the section from the arch of aorta to the point where it divides into the common iliac arteries
• Thoracic aorta—the half of the descending aorta above the diaphragm
• Abdominal aorta—the half of the descending aorta below the diaphragm

In other animals

All amniotes have a broadly similar arrangement to that of humans, albeit with a number of individual variations. In fish, however, there are two separate vessels referred to as aortas. The ventral aorta carries de-oxygenated blood from the heart to the gills; part of this vessel forms the ascending aorta in tetrapods (the remainder forms the pulmonary artery). A second, dorsal aorta carries oxygenated blood from the gills to the rest of the body, and is homologous with the descending aorta of tetrapods. The two aortas are connected by a number of vessels, one passing through each of the gills. Amphibians also retain the fifth connecting vessel, so that the aorta has two parallel arches