Where are blood vessels located?
Blood vessels run all through your body. Branches from large vessels get smaller and smaller, reaching every organ in your body. You have billions of blood vessels in your body, and most of them are capillaries, venules and arterioles. These smaller vessels connect to 160 arteries and 200 veins.
Your most important blood vessel is your body’s main artery — your
. This is a large artery that carries blood away from your heart and delivers oxygen-rich blood to your body. Your aorta runs down through your chest,
and abdomen (belly), branching off in many areas. Near your
, this main artery branches into two arteries that supply blood to your lower body and legs.
The main vein in your body is the
. The superior vena cava is in the upper right part of your chest. It takes blood from your head, neck, arms and chest back to your heart. The inferior vena cava is near the right side of your diaphragm. It brings blood from your legs, feet, abdomen and pelvis back to your heart.
What are the parts of blood vessels?
Blood vessel anatomy includes three layers of tissue:
Tunica intima.This inner layer surrounds the blood as it flows through your body. It regulates
, prevents
and keeps toxins out of your blood. It keeps your blood flowing smoothly.
Media.The middle layer contains elastic fibers that keep your blood flowing in one direction. The media also helps vessels expand and contract.
Adventitia.The outer layer contains
and tiny vessels. It delivers oxygen and nutrients from your blood to your cells and helps remove waste. It also gives blood vessels their structure and support.
What do blood vessels look like?
Blood vessels have a tube-like shape, but they rarely run in a straight line. Some are big enough to see under your
. If you’ve ever had your blood drawn, you may have noticed veins on the inside of your arm. They might appear blue under your skin, even though your blood is red.