Free Term Paper on the Aorta
The ascending aorta, or aorta ascendens, along with its constituents,
amounts to about five centimeters in length. It constitutes the initial division
of the aorta, the largest artery in the body. It originates from the upper
portion of the left ventricle of the heart at the aortic valve “on a level with
the lower border of the third costal cartilage behind the left half of the
sternum; it passes obliquely upward, forward, and to the right, in the direction
of the heart’s axis, as high as the upper border of the second right costal
cartilage, describing a slight curve in its course, and being situated, about 6
cm. behind the posterior surface of the sternum.” (Gray” 1) It then gives rise
to the right and left coronary arteries, which supply the heart muscle. It then
curves left continuing into the arch of the aorta. Originating from the aorta
are the right brachiocephalic trunk, left common carotid, and left subclavian
arteries. The coronary arteries, thus being, the only branches of the ascending
aorta.
At the entrance of the ascending aorta are three minute aortic
sinuses and the Aortic Semilunar Valve, a three-cusped valve located at the base
of the ascending aorta behind the sternum at the level of the third intercostal
space (Grine 273). The point at which the ascending aorta converges with the
aortic arch is termed the bulb of the aorta, a swelling due to vessel
increasement on the right wall. Lying superior to the ascending aorta is the
trunk of the pulmonary artery and the auricular appendage of the right atrium.
It is partitioned from the sternum by the serous pericardium, the right pleura,
the anterior margin of the right lung, some loose areolar tissue, and the
remains of the thymus. Posteriorly, it is propped upon the left atrium and right
pulmonary artery. Lying adjacent on the right border is the superior vena cava
and right atrium. Lying opposite on the left border is the pulmonary artery and
pulmonary trunk (Gray” 1). The ascending aorta is, thus, “ a hallowed and
convenient division of the aorta” (“MedicineNet” 1) that supplies blood to most
of the body.
Works Cited
Gray, Henry,
http://www.bartleby.com. 21 Apr 2002.
Grine, Fredrick E., Regional Human
Anatomy: A Laboratory Workbook for Use with
Models and Prosections. New
York, McGraw-Hill Companies, 2002.
http://www.medicinenet.com. 21 Apr
2002.