GENERAL HISTOLOGY

Detailed explanation-1: -These are the blood vessels that carry deoxygenated blood from different tissues of the body toward the heart. Semilunar valves : These valves guard the opening to the pulmonary artery and the ventricles to prevent blood from returning to the atria when the ventricles contract.

Detailed explanation-2: -Unlike arteries, veins contain valves that ensure blood flows in only one direction. But, Arteries don’t require valves because pressure from the heart is so strong that blood is only able to flow in one direction.

Detailed explanation-3: -Blood flow within your legs occurs mainly through the deep venous system. Femoral veins typically have between one to six vein valves, and popliteal veins often contain between zero to four valves. Valves in veins are bicuspid, meaning they have two flap-like structures that regulate blood flow.

Detailed explanation-4: -The valveless veins are veins that lack venous valves. Most veins contain valves (known as the valvula venosa in the TA) to prevent backflow, i.e. ensuring that blood flow is always towards the heart 1.