Comparative Histomorphology and Histochemistry of Thoracic Aorta in Deccani Sheep and Bidri Goat

Thoracic aorta were elastic type, tunica intima consisted of a single layer of flattened endothelial cells, sub endothelial layer and indistinct internal elastic membrane. Tunica media is thickest among the three layers and welldefined elastic lamellae, they were separated by circularly arranged smooth muscle, collagen fibers and reticular fibers. External elastic membrane was not distinguishable from many elastic layers in tunica media and tunica adventitia was comprised of collagen fibers, elastic fibers, vasa vasorum and fibroblasts in loose connective tissue. Histochemically thoracic aorta of both the species showed strong (+++) PAS positive in the tunica intima of Bidri goat and Deccani sheep. Tunica media showed moderate (++) alcian blue (pH 1.0) reaction in sheep, whereas, in goat it was strong (+++) alcian blue reaction and tunica adventitia was strong (+++) PAS positive in Deccani sheep whereas, in goat it was strong (+++) alcian blue positive.