Veins are blood vessels that carry oxygen-poor blood to your heart. The only exception to this is pulmonary veins, which carry oxygen-rich blood from your lungs to your heart. They are a vital part of your circulatory system, working alongside arteries and capillaries to deliver oxygen and nutrients throughout your body.
Veins have thinner walls than arteries and have valves that help prevent blood from flowing backward. They can be found throughout your body, with larger veins located closer to the surface of the skin.
Here are some additional insights:
- Types of veins: Veins come in three sizes: large, medium, and small. The smallest veins are called venules, and the smallest of these, the post-capillary venules, are microscopic.
- Varicose veins: Varicose veins are swollen, twisted veins that are usually found in the legs. They occur when the valves in the veins weaken and don't work properly, causing blood to pool in the veins.
- Blood vessel function: Blood vessels carry oxygen-rich blood throughout your body and then return it to your heart. This is how your body receives the oxygen and nutrients it needs to function.
