Vol. 12, Issue 3 (2023)

The wall of coronary arteries was made up of three layers viz., tunica intima, tunica media and tunica adventitia. The tunica intima was made up of endothelium, subendothelial tissue and internal elastic membrane. The tunica media consisted of bundles of smooth muscle fibres intermingled with elastic and collagen fibres. The tunica adventitia was made up of loose connective tissue with collagen, elastic and nerve fibres. The thickness of tunica intima of coronary arteries increased with advancement of the age of the animal from group-I to group-II and reduced in group-III. Multiple splitting of the internal elastic membrane of coronary arteries was observed in Group-I and Group-II, duplicated, fragmented and discontinuous internal elastic membrane was observed in Group-III. The thickness of tunica media of the coronary arteries increased with advancement in age of the animal from group-I to group-III. The thickness of tunica media of right coronary artery was more than left coronary artery. The wall of right coronary artery was thicker than the wall of left coronary artery in all the three age groups.