Structural Features in Tunica Media of the Aorta in Lamb

Abstract

In blood vessels situated just after the heart, an irregular blood flow occurs due to some specific structural elements of the tunica media. The current paper describes the histological aspects of some post-cardiac arterial sections in lamb. The tissue samples were collected from five 30 days old male lambs (Țurcană breed). Histological specimens from different regions of the aorta were harvested (i.e., the ascending aorta, aortic arch, thoracic and abdominal regions of the descending aorta). From the specified regions, small pieces (cca. 0.5 cm) were fixed in neutral 10% buffered formalin. The tissues were subsequently embedded in paraffin wax, sectioned at 5 μm, and stained with Goldner’s trichrome and Verhoeff methods. Tissue analysis was performed using an Olympus system for image acquisition and analysis. Histological appearance of the assessed segments of the aorta in lamb is unusual. Major changes occur in tunica media of the aorta. In the ascending aorta, aortic arch and thoracic regions of the aorta, the histological outline is somewhat the same. The internal region of the media possesses the typical lamellar arrangement. Concerning the outer part of tunica media, the smooth muscle has a tendency to form bundles of various sizes. The muscle islands are not present in the media of abdominal region of the aorta, which exhibits the classic pattern of elastic arteries.