An elastic artery (conducting artery or conduit artery) is an

artery An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...

with many

collagen Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...

and

elastin Elastin is a protein encoded by the ''ELN'' gene in humans and several other animals. Elastin is a key component in the extracellular matrix of gnathostomes (jawed vertebrates). It is highly Elasticity (physics), elastic and present in connective ...

filaments in the

tunica media The tunica media (Neo-Latin "middle coat"), or media for short, is the middle tunica (layer) of an artery or vein. It lies between the internal elastic lamina of the tunica intima on the inside and the tunica externa on the outside. Artery The ...

, which gives it the ability to stretch in response to each pulse. This elasticity also gives rise to the Windkessel effect, which helps to maintain a relatively constant pressure in the arteries despite the pulsating nature of the blood flow. Elastic arteries include the largest arteries in the body, those closest to the heart. They give rise to medium-sized vessels known as distributing arteries (or ''muscular arteries''). The

pulmonary arteries A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the ''main pulmonary artery'' or ''pulmonary trunk'' from the heart, and ...

, the

aorta The aorta ( ; : aortas or aortae) is the main and largest artery in the human body, originating from the Ventricle (heart), left ventricle of the heart, branching upwards immediately after, and extending down to the abdomen, where it splits at ...

, and its branches together comprise the body's system of elastic arteries. Other examples include the brachiocephalic artery, common carotid arteries, subclavian artery, and common iliac artery.

Structure

The most prominent feature of elastic arteries is the very thick

in which elastic lamellae alternate with layers of smooth muscle fibers. The adult aorta has about 50 elastic lamellae. The tunica intima is well developed, with many smooth muscle cells in the subendothelial

connective tissue Connective tissue is one of the four primary types of animal tissue, a group of cells that are similar in structure, along with epithelial tissue, muscle tissue, and nervous tissue. It develops mostly from the mesenchyme, derived from the mesod ...

, and often shows folds in cross section because of the vessel’s contraction with loss of

blood pressure Blood pressure (BP) is the pressure of Circulatory system, circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term ...

at death. Between the intima and the media lies the internal elastic lamina, usually better defined than the elastic laminae of the media. The relatively thin adventitia contains vasa vasorum, which also supply elastic arteries, unlike smaller blood vessels, which are supplied by

diffusion Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical p ...

Physiology

The numerous elastic laminae of these arteries contribute to their important function of making

blood flow Hemodynamics American and British English spelling differences#ae and oe, or haemodynamics are the Fluid dynamics, dynamics of blood flow. The circulatory system is controlled by homeostasis, homeostatic mechanisms of autoregulation, just as hydrau ...

more uniform. During ventricular contraction (

systole Systole ( ) is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood. Its contrasting phase is diastole, the relaxed phase of the cardiac cycle when the chambers of the heart are refilling ...

), blood moves through the arteries forcefully, stretching the

and distending the wall within limits set by its content of

. When the ventricles relax ( diastole), ventricular pressure drops to a low level, and the elastin layers rebound passively, helping to maintain arterial pressure. The aortic and pulmonary valves prevent backflow of blood into the heart, so blood continues to flow away from the heart during this rebound. Arterial blood pressure and blood velocity decrease and become less variable as the distance from the heart increases.

References

External links

*
Histology at usc.edu
{{Authority control Arteries