PATHOLOGY

Detailed explanation-1: -Veins: Unlike arteries, veins don’t have to carry highly pressurized blood, but they do have to carry large volumes of deoxygenated blood back to your heart. Thin, less elastic walls help them handle high volumes and low pressure. Most veins have valves that open and close.

Detailed explanation-2: -The superior vena cava is the large vein that brings blood from the head and arms to the heart, and the inferior vena cava brings blood from the abdomen and legs into the heart.

Detailed explanation-3: -Veins often pump blood against the flow of gravity and make use of valves to prevent the blood from flowing downwards.

Detailed explanation-4: -Veins have valves that prevent the backward flow of the blood.