NEET PG DENTAL EXAM

Detailed explanation-1: -Blood vessels are composed of three layers (tunics). The innermost layer is the tunica intima, the middle layer is the tunica media, and the outermost layer is the tunica externa. The tunica media contains the muscular portion of the vessel and is directly involved in vasoconstriction and vasodilation.

Detailed explanation-2: -Specifically in arteries, vasoconstriction decreases blood flow as the smooth muscle in the walls of the tunica media contracts, making the lumen narrower and increasing blood pressure. Similarly, vasodilation increases blood flow as the smooth muscle relaxes, allowing the lumen to widen and blood pressure to drop.

Detailed explanation-3: -Blood Vessel Structure Moving towards the lumen, the next layer is the tunica media composed of smooth muscle, connective tissue, and elastic fibers. This is where vasoconstriction takes place.

Detailed explanation-4: -The middle layer, the tunica media, is primarily smooth muscle and is usually the thickest layer. It not only provides support for the vessel but also changes vessel diameter to regulate blood flow and blood pressure.