Biology of the Blood Vessels
Blood vessels are hollow tubes like pipes that carry blood through your body. The blood delivers oxygen and nutrients to all parts of your body and removes waste products, such as carbon dioxide.
Arteries have thick walls lined with muscle. Arteries need to be strong because blood pressure is highest in the arteries. Muscles of your arteries constantly squeeze and relax to help adjust your blood pressure.
Veins have thin walls with only a little muscle. Blood pressure is lower in the veins. Veins can get wider to handle increased blood. Some veins have valves to keep the blood from flowing backward.
Your blood vessels and your heart are parts of the cardiovascular system.
Blood Vessels: Circulating the Blood
If a blood vessel is cut or tears, you bleed, either on the outside or internally within your organs. Other common blood vessel problems include:
Atherosclerosis (hardening of the arteries), in which fat deposits block your arteries
Aneurysms, which are bulges in weak areas of the walls of your arteries
Blood clots can form in your veins (called deep vein thrombosis) or in your arteries, causing sudden blockage
Vasculitis, in which your blood vessels become inflamed
Varicose veins, in which veins near the surface of your skin get enlarged and twisted