| Elastic artery | |
|---|---|
| Details | |
| System | Cardiovascular system |
| Identifiers | |
| TH | H3.09.02.0.01010 |
| Anatomical terminology | |
Anelastic artery (conducting artery orconduit artery) is anartery with manycollagen andelastin filaments in thetunica media, which gives it the ability to stretch in response to each pulse.[1] This elasticity also gives rise to theWindkessel effect, which helps to maintain a relatively constant pressure in the arteries despite the pulsating nature of the blood flow.[2] Elastic arteries include the largest arteries in the body, those closest to the heart. They give rise to medium-sized vessels known asdistributing arteries (ormuscular arteries).
Thepulmonary arteries, theaorta, and its branches together comprise the body's system of elastic arteries. Other examples include thebrachiocephalic artery,common carotid arteries,subclavian artery, andcommon iliac artery.
The most prominent feature of elastic arteries is the very thicktunica media in which elastic lamellae alternate with layers ofsmooth muscle fibers. The adult aorta has about 50 elastic lamellae.[3]
Thetunica intima is well developed, with many smooth muscle cells in the subendothelialconnective tissue, and often shows folds in cross section because of the vessel’s contraction with loss ofblood pressure at death. Between the intima and the media lies theinternal elastic lamina, usually better defined than the elastic laminae of the media. The relatively thin adventitia containsvasa vasorum, which also supply elastic arteries,[3] unlike smaller blood vessels, which are supplied bydiffusion.
The numerous elastic laminae of these arteries contribute to their important function of makingblood flow more uniform. During ventricular contraction (systole), blood moves through the arteries forcefully, stretching theelastin and distending the wall within limits set by its content ofcollagen. When the ventricles relax (diastole), ventricular pressure drops to a low level, and the elastin layers rebound passively, helping to maintainarterial 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.[3]