Bock, Walter J. Department of Biological Sciences, Columbia University, New York, New York.
Last reviewed:November 2019
Show previous versions
- Related Primary Literature
- Additional Reading
The main vessel of the systemic arterial circulation arising from the heart. The aorta (see illustration) is the main artery leaving the heart in all vertebrates and some invertebrates. In mammals, reptiles, and birds, which possess two heart ventricles (muscular chambers that pump blood out of the heart), the aorta arises from the left ventricle. Divided into three parts for convenience only, the aorta carries blood from the heart to various organs and other structures of the body. The first portion is termed the ascending aorta and passes upward under the pulmonary artery; the coronary arteries arise at the base of the ascending aorta behind the aortic valves. The second part, or aortic arch, curves over the hilum of the left lung, giving off the innominate, left carotid, and left subclavian arteries, which supply the neck, head, and forelimbs. The third portion, or descending aorta, continues downward in the thorax on the left side of the vertebral column to the diaphragm, giving off small arteries to the bronchi, esophagus, and other adjacent tissues. Below the diaphragm, the vessel known as the abdominal aorta descends to the level of the fourth lumbar vertebra, where it bifurcates into the two common iliac arteries supplying the hindlimbs. See also: Blood; Blood vessel; Cardiovascular system; Circulation; Heart (invertebrate); Heart (vertebrate)
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information