Medium vein

Accompanying this medium vein is a muscular artery, with its dominant tunica media. Veins possess wider lumens, thinner walls and more irregular outlines compared with arteries. Longitudinally-oriented smooth muscle may be present in the tunica adventitia. Veins also possess valves consisting of intimal folds that extend into the lumen to prevent the back flow of blood. Arteries do not possess valves. 100x

Accompanying this medium vein is a muscular artery, with its dominant tunica media. Veins possess wider lumens, thinner walls and more irregular outlines compared with arteries. Longitudinally-oriented smooth muscle may be present in the tunica adventitia. Veins also possess valves consisting of intimal folds that extend into the lumen to prevent the back flow of blood. Arteries do not possess valves. 100x

Accompanying this medium vein is a muscular artery, with its dominant tunica media. Veins possess wider lumens, thinner walls and more irregular outlines compared with arteries. Longitudinally-oriented smooth muscle may be present in the tunica adventitia. Veins also possess valves consisting of intimal folds that extend into the lumen to prevent the back flow of blood. Arteries do not possess valves. 100x

Valves are particularly prominent in veins of the lower extremity where they prevent the “back-flow” of blood due to gravity. Blood pressure on the venous side of the circulatory system is low and venous return to the heart is accomplished primarily by contraction of adjacent skeletal muscle, which produces a milking action in the vein.

Accompanying this medium vein is a muscular artery, with its dominant tunica media. Veins possess wider lumens, thinner walls and more irregular outlines compared with arteries. Longitudinally-oriented smooth muscle may be present in the tunica adventitia. Veins also possess valves consisting of intimal folds that extend into the lumen to prevent the back flow of blood. Arteries do not possess valves. 100x

Accompanying this medium vein is a muscular artery, with its dominant tunica media. Veins possess wider lumens, thinner walls and more irregular outlines compared with arteries. Longitudinally-oriented smooth muscle may be present in the tunica adventitia. Veins also possess valves consisting of intimal folds that extend into the lumen to prevent the back flow of blood. Arteries do not possess valves. 100x

Accompanying this medium vein is a muscular artery, with its dominant tunica media. Veins possess wider lumens, thinner walls and more irregular outlines compared with arteries. Longitudinally-oriented smooth muscle may be present in the tunica adventitia. Veins also possess valves consisting of intimal folds that extend into the lumen to prevent the back flow of blood. Arteries do not possess valves. 100x