aorta

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aorta
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aorta

A. arch of aorta
B. abdominal aorta
(Carlyn Iverson)
(ā-ôr') pronunciation
n., pl., -tas, or -tae (-tē).
The main trunk of the systemic arteries, carrying blood from the left side of the heart to the arteries of all limbs and organs except the lungs.

[New Latin, from Greek āortē, from āeirein, to lift.]

aortal a·or'tal or a·or'tic adj.


Artery that carries blood from the heart to all the organs and structures of the body. Where the left ventricle opens into the aorta, a valve prevents backflow of blood into the heart. The aorta ascends from the heart, arches over it to the left, then descends into the trunk. Arteries branch off along its length until it divides at hip level into arteries that go to the legs.

For more information on aorta, visit Britannica.com.

The main vessel of the systemic arterial circulation arising from the left ventricle of the heart; it is divided into three parts for convenience only. The first portion, the ascending aorta, 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 this 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.

In the abdomen the major branches of the aorta include the single celiac, superior mesenteric and inferior mesenteric, and the paired renal and internal spermatic (male) or ovarian (female) arteries. In addition, many small branches go to other organs and to the body wall.


The major artery in the body. It carries blood from the left ventricle of the heart.

aorta (āôr'), primary artery of the circulatory system in mammals, delivering oxygenated blood to all other arteries except those of the lungs. The human aorta, c.1 in. (2.54 cm) in diameter, originates at the left ventricle of the heart. After supplying the coronary arteries that nourish the heart itself, the aorta extends slightly toward the neck to feed branches serving the head and arms. It then arches down toward the waist, directing blood into the arterial system of the chest. Entering the abdomen through the aortic hiatus, an opening in the diaphragm, the aorta branches off to supply the stomach, kidneys, intestines, gonads, and other organs through extensive arterial networks. It finally divides into the two iliac arteries carrying blood to the legs. The elasticity of the aorta wall permits it to pulse in rhythm with the heartbeat, thus helping to propel blood through the body.


(ay-awr-tuh)

The main blood vessel of the body; it carries blood from the left side of the heart to other arteries throughout the body. (See circulatory system.)

Pl. aortae, aortas [L.] the great artery arising from the left ventricle, being the main trunk from which the systemic arterial system proceeds. See also aortic.

  • abdominal a. — the part of the descending aorta within the abdomen.
  • ascending a. — the first part of the aorta which passes dorsally and cranially.
  • descending a. — the aorta after it turns caudally at the aortic arch.
  • overriding a. — see overriding aorta.
  • supravalvular a. — the portion of aorta immediately above the aortic valve.
  • terminal a. — the segment of the aorta immediately before it divides into the iliac arteries.
  • thoracic a. — the part of the descending aorta within the thorax.

n

The main arterial trunk of the systemic circulation. Consists of four parts: the ascending aorta, the arch of the aorta, the thoracic portion of the descending aorta, and the abdominal portion of the descending aorta.

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Artery: Aorta
Aorta scheme noTags.svg
Schematic view of the aorta and a number of its most important branches
Aorta 2.jpg
The ascending aorta as it leaves the heart
Latin Aorta, arteria maxima
Supplies The entire body with exception of the respiratory zone of the lung
Source Left ventricle   
Branches Ascending aorta:
Right and left coronary arteries.

Arch of aorta (supra-aortic vessels):

Brachiocephalic trunk
Left common carotid artery
Left subclavian artery

Descending aorta, thoracic part:

Left bronchial arteries
Oesophageal arteries to the thoracic part of the Oesophagus
Third to eleventh Posterior intercostal arteries, and the Subcostal arteries

Descending aorta, abdominal part:

Parietal branches:
Inferior phrenic arteries
Lumbar arteries
Median sacral artery
Visceral branches:
Coeliac trunk
Middle suprarenal arteries
Superior mesenteric artery
Renal arteries
Gonadal arteries testicular in males, ovarian in females
Inferior mesenteric artery

Terminal branches:

Common iliac arteries
Vein Combination of coronary sinus, superior vena cava and inferior vena cava
Precursor Truncus arteriosus

Fourth left branchial artery

Paired dorsal aortae (combine into the single descending aorta)

The aorta (play /ˈɔrtə/; from Greek ἀορτή - aortē, from ἀείρω - aeirō "I lift, raise")[1] 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.[2]

Contents

The course of the aorta

Course of the aorta (anterior view), starting posterior to the main pulmonary artery, but then anterior to the right pulmonary arteries, the trachea and the esophagus, but then turning posteriorly to course dorsally to these structures.

The aorta is usually divided into five segments/sections:[3][4]

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.[5]

Embryological development

In mammalian and avian embryological development, the pharyngeal arch (aortic arches) arteries contribute to the normal pattern of the great arteries. The fourth aortic arch vessel survives in these vertebrates as the arch of the aorta, the third aortic arch vessel persists as the brachiocephalic artery or the root of the internal carotid, and the six arch contributes to the pulmonary arteries. The smooth muscle of the great arteries and the population of cells that form the aorticopulmonary septum that separates the aorta and pulmonary artery is derived from cardiac neural crest. This contribution of the neural crest to the great artery smooth muscle is unusual as most smooth muscle is derived from mesoderm. In fact the smooth muscle within the abdominal aorta is derived from mesoderm, and the coronary arteries, which arise just above the semilunar valves, possess smooth muscle of mesodermal origin. A failure of the aorticopulmonary septum to divide the great vessels results in persistent truncus arteriosus.

Aorta and pulmonary artery - dissection of fetal heart

Features

A pig's aorta cut open showing also some leaving arteries.

The aorta is an elastic artery, and as such is quite distensible. Mean arterial blood pressure is highest in the aorta and mean arterial pressure diminishes across the circulation from aorta to arteries to arterioles to capillaries to veins back to atrium: the difference between aortic and right atrial pressure accounts for blood flow in the circulation.[6] The aorta consists of a heterogeneous mixture of smooth muscle, nerves, intimal cells, endothelial cells, fibroblast-like cells, and a complex extracellular matrix. The vascular wall consists of several layers known as the tunica adventitia, tunica media, and tunica intima. The thickness of the aorta encourages an extensive network of tiny blood vessels called vasa vasorum, which feed the outer layers of the aorta. The aortic arch contains baroreceptors and chemoreceptors that relay information concerning blood pressure and blood pH and carbon dioxide levels to the medulla oblongata of the brain. This information is processed by the brain and the autonomic nervous system mediates the homeostatic responses.

Within the tunica media, smooth muscle and the extracellular matrix are quantitatively the largest components of the aortic vascular wall. The fundamental unit of the aorta is the elastic lamella, which consists of smooth muscle and elastic matrix. The medial layer of the aorta consist of concentric musculoelastic layers (the elastic lamella) in mammals. The smooth muscle component does not dramatically alter the diameter of the aorta but rather serves to increase the stiffness and viscoelasticity of the aortic wall when activated. The elastic matrix dominates the biomechanical properties of the aorta. The elastic matrix forms lamella, consisting of elastic fibers, collagens(predominately type III), proteoglycans, and glycoaminoglycans. When the left ventricle contracts to force blood into the aorta, the aorta expands. This stretching gives the potential energy that will help maintain blood pressure during diastole, as during this time the aorta contracts passively. This Windkessel effect of the great elastic arteries has important biomechanical implications. The elastic recoil helps conserve the energy from the pumping heart and smooth out the pulsatile nature created by the heart. Aortic pressure is highest at the aorta and becomes less pulsatile and lower pressure as blood vessels divide into arteries, arterioles, and capillaries such that flow is slow and smooth for gases and nutrient exchange.

Blood flow and velocity

The pulsatile nature of blood flow creates a pulse wave that is propagated down the arterial tree, and at bifurcations reflected waves rebound to return to semilunar valves and the origin of the aorta. These return waves create the dicrotic notch displayed in the aortic pressure curve during the cardiac cycle as these reflected waves push on the aortic semilunar valve.[7] With age, the aorta stiffens such that the pulse wave is propagated faster and reflected waves return to the heart faster before the semilunar valve closes, which raises the blood pressure. The stiffness of the aorta is associated with a number of diseases and pathologies, and noninvasive measures of the pulse wave velocity are an independent indicator of hypertension. Measuring the pulse wave velocity (invasively and non-invasively) is a means of determining arterial stiffness. Maximum aortic velocity may be noted as Vmax or less commonly as AoVmax.


Diseases/pathology

References

  1. ^ Illustrated Steadman's Dictionary, 24th ed.
  2. ^ Maton, Anthea; Jean Hopkins, Charles William McLaughlin, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright (1995). Human Biology Health. Englewood Cliffs, New Jersey: Prentice Hall. ISBN 0-13-981176-1. 
  3. ^ Tortora, Gerard J: "Principles of Human W. & Karen A. Koos: Human Anatomy, second edition, page 479. Wm. C. Brown Publishing, 1994. (ISBN 0-697-12252-2)
  4. ^ De Graaff, Van: "Human Anatomy, fifth edition", pages 548-549. WCB McGraw-Hill, 1998. (ISBN 0-697-28413-1)
  5. ^ Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. pp. 419–421. ISBN 0-03-910284-X. 
  6. ^ Nichols WW, O'Rourke MF. McDonald's Blood Flow in Arteries: Theoretical, Experimental and Clinical Principles. 4th ed. London, UK: Edward Arnold; 1998
  7. ^ Seeley, Rod; Stephens, Trent; Philip Tate (1992). "20". In Allen, Deborah. Anatomy and physiology (2 ed.). Mosby-Year Book, Inc. p. 631. ISBN [[Special:BookSources/00801648327|00801648327]]. 
  8. ^ Samett EJ. http://www.emedicine.com/radio/topic44.htm Aorta, Trauma. eMedicine.com. Accessed on: April 24, 2007.
  9. ^ Tambyraja, A; Scollay, JM; Beard, D; Henry, JM; Murie, JA; Chalmers, RT (2006). "Aortic Trauma in Scotland - A Population Based Study". European Journal of Vascular and Endovascular Surgery 32 (6): 686–689. DOI:10.1016/j.ejvs.2006.04.006. PMID 16750920. 

External links


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Dansk (Danish)
n. - aorta

Nederlands (Dutch)
aorta (lichaamsslagader)

Français (French)
n. - aorte

Deutsch (German)
n. - Aorta, Hauptschlagader

Ελληνική (Greek)
n. - (ανατ.) αορτή

Italiano (Italian)
aorta

Português (Portuguese)
n. - aorta (f) (Anat.)

Русский (Russian)
аорта

Español (Spanish)
n. - aorta

Svenska (Swedish)
n. - aorta (anat.)

中文(简体)(Chinese (Simplified))
大动脉

中文(繁體)(Chinese (Traditional))
n. - 大動脈

한국어 (Korean)
n. - 대동맥

日本語 (Japanese)
n. - 大動脈

العربيه (Arabic)
‏(الاسم) الوتين : الشريان الأورطي‏

עברית (Hebrew)
n. - ‮אב-עורקים, אבעורק‬


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