What Are Veins? ‌Your blood loses oxygen as it travels through your arteries. Veins carry the blood back to your heart to absorb more oxygen. Your veins usually hold about 75% of all the blood flowing through your body.‌ Your largest veins are the superior and inferior vena cava.

What is veins and its function?

Veins are a type of blood vessel that return deoxygenated blood from your organs back to your heart. These are different from your arteries, which deliver oxygenated blood from your heart to the rest of your body. Deoxygenated blood that flows into your veins is collected within tiny blood vessels called capillaries.

What is a human vein?

vein, in human physiology, any of the vessels that, with four exceptions, carry oxygen-depleted blood to the right upper chamber (atrium) of the heart. The four exceptions—the pulmonary veins—transport oxygenated blood from the lungs to the left upper chamber of the heart.