Assessment of the Elastic Component in Tunica Adventitia of Some Arteries in Lamb

Abstract

Tunica adventitia of large caliber vessels in lambs presents a highly different thickness from one segment to another, depending on its position in relation to the heart and the irrigated area. In the case of all the studied arteries, adventitia is formed out of collagen and elastic fibers. In some arteries, adventitia contains a small quantity of elastic fibers (ascending aorta, aortic arch, thoracic descending aorta, bicarotid trunk, left subclavian artery). Other arteries contain elastic fibers in a markedly larger quantity, without exceeding a certain limit (abdominal descending aorta, left and right internal iliac arteries, brachiocephalic trunk, right subclavian artery). There are also vessels in which the elastic component from tunica adventitia is formed out of thick and numerous fibers, so that the elastic component in adventitia markedly exceeds the one from tunica media (left and right external iliac arteries, left and right carotid arteries). The large quantity of elastic tissue in tunica adventitia of these vessels seems to be an adaptation to the external solicitations that exert upon them, in direct relation to the irrigated anatomical area.