The central vessel
Section of the aorta
The aorta can be roughly divided into the following sections:
The first section, which originates from the left ventricle, is ascending and is called the ascending aorta. It lies within the pericardium and has two branches – the two coronary arteries that supply the heart muscle.
The aortic arch is followed by the descending section of the aorta, the descending aorta. It runs first in the chest cavity (then called the thoracic aorta) and then – after passing through the diaphragm – in the abdominal cavity (then called the abdominal aorta). The branches of the thoracic aorta supply the lungs, chest wall, and adjacent thoracic viscera. The branches of the abdominal aorta supply the abdominal organs.
Structure of the aorta
Like all large blood vessels, the wall of the aorta has three layers:
- inner layer (intima)
- middle layer (media, tunica media)
- outer layer (adventitia, tunica externa)
The aorta belongs to the arteries of the elastic type. This means that the middle layer is particularly thick and contains many elastic fibers.
The tasks of the aorta
The pumping heart creates large pressure differences in the circulatory system through contraction (systole) and relaxation (diastole). Due to its elasticity, the aorta can compensate for these and thus enable a continuous blood flow. Through this “wind kettle” function, it maintains the arterial blood pressure (120/80 mmHg in a healthy person) so that it still exists in more distant parts of the body.
Diseases of the aorta
An abnormal sac- or spindle-shaped enlargement of the aorta is called an aortic aneurysm. If it ruptures suddenly, the affected person can bleed to death internally.
Aortic dissection is the term used by physicians to describe a sudden tear in the inner skin (intima) of the aorta, caused by arteriosclerosis or an accident, for example. In extreme cases, the aorta can rupture at the affected site, which then (as with a ruptured aortic aneurysm) means danger to life!
