👉 Veins are the blood vessels that carry deoxygenated blood (blood returning to the heart) back to the heart and lungs. Unlike arteries, veins have thinner walls and larger valves to prevent blood from flowing backward. The name "veins" comes from the Latin word "vena," meaning "gathering," because they collect blood from various parts of the body. The veins are typically blue or purple in color due to deoxygenated blood and lack of oxygen in their walls.
