MICROANATOMY

Detailed explanation-1: -In addition, veins contain valves to prevent backflow of blood while smooth muscle cells in the vascular wall allow veins to constrict and increase the blood pressure, both of which increase venous return [13].

Detailed explanation-2: -Veins often pump blood against the flow of gravity and make use of valves to prevent the blood from flowing downwards.

Detailed explanation-3: -What are Vein Valves? Interspersed throughout your veins are small crescent-shaped flaps of tissue, known as valves, that help prevent a backflow of blood. These valves project from the innermost layer of the vein wall to the center of the vein and are angled towards the heart in the direction of venous blood flow.