Human Anatomy and Physiology - N. I. Fedyukovich 2003

Cardiovascular System
Blood Vessels of the Systemic Circulation

The systemic Circulation begins in the left ventricle, from which the aorta emerges, and ends in the right atrium.

The primary function of the systemic Blood Vessels is to deliver oxygen, nutrients, and Hormones to Organs and Tissues. Metabolic exchange between blood and tissue Cells occurs at the capillary level, while Metabolic waste products are cleared from the organs via the Venous system.

The Blood Vessels of the Systemic Circulation include the aorta with its branching Arteries supplying the HEAD, neck, trunk, and limbs, the branches of these arteries, smaller organ-level vessels including capillaries, and small to large Veins that ultimately converge into the superior and inferior venae cavae.

The aorta is the largest unpaired arterial vessel in The Human Body. It is divided into the ascending aorta, the aortic arch, and the descending aorta. The latter is further subdivided into the thoracic and abdominal parts.

The ascending aorta begins with an expansion called the bulb, emerges from the left ventricle at the level of the third left intercostal space posterior to the Sternum, ascends, and transitions into the aortic arch at the level of the second costal Cartilage. The ascending aorta is approximately 6 cm long and gives rise to the right and left coronary arteries, which supply The Heart with blood.

The aortic arch begins at the second costal cartilage, curves to the left and posteriorly toward the body of the fourth thoracic vertebra, where it continues as the descending aorta. At this junction, There is a slight narrowing known as the aortic isthmus. Major vessels branch off the aortic arch (the brachiocephalic trunk, left common carotid artery, and left Subclavian Artery), supplying blood to the neck, head, upper torso, and upper extremities.

The descending aorta is the longest section of the aorta, extending from the level of the fourth thoracic vertebra down to the fourth lumbar vertebra, where it bifurcates into the right and left common iliac arteries; this branching point is known as the aortic bifurcation. The descending aorta is subdivided into the thoracic and Abdominal Aorta.