An: 2012, Nr.3, Articol Nr. 9
THE LAYER OF THE AORTIC SMOOTH MUSCLE CELLS AN IMPORTANT DETERMINANT OF ARTERIAL ELASTICITY
Corina Ciupilan, M.D. Scutariu - University of Medicine and Pharmacy “Gr. T. Popa” Iaşi, Faculty of Medicine, Department of Anatomy
THE LAYER OF THE AORTIC SMOOTH MUSCLE CELLS AN IMPORTANT DETERMINANT OF ARTERIAL ELASTICITY (Abstract): Aorta pushes the blood flow in the periods of time between the contractions of the heart, but also for assuring the proper resistance in relation to the high blood pressure during contractions. The structure of the arterial vascular wall varies according to the hemodynamic or metabolic necessity of different regions of the body. Thus, at the level of the large arteries, the media is very rich in elastic fibers disposed in compact layers that alternate with smooth muscle cells. The layer of smooth muscle cells has various functions including the regulation of the vasomotor tonus as an answer to various stimuli, the synthesis of collagen and elastin, creation of growth factors and cytokines, the intimal migration and proliferation. So, it represents an important element of arterial elasticity. The contracting activity of smooth muscle cells is mediated by the cytoplasmic filaments that contain actin and myosin; the intimal migration and proliferation activity is regulated by promoters or cellular growth inhibitors. Apart from the main contracting mechanism (myosin dependent) numerous other biochemical accessory and regulation passages interfere in the contraction of the smooth muscle at the level of miofilaments, some of which actin dependent, involving certain specialized proteins as caldes¬mona and calponina meant to fix the actin.
Key words: AORTA, SMOOTH MUSCLES, VASCULAR WALL, SMOOTH MYOCYTES, ENDOTHELIAL CELLS