👉 Veins are thin-walled, elastic blood vessels that carry deoxygenated blood back to the heart. Unlike arteries, veins have thinner walls and larger diameters, making them less efficient at transporting blood against gravity. They contain one-way valves that prevent blood from flowing backward and back into the veins. These valves ensure that blood moves upward toward the heart, where it can be oxygenated again.
