What’s the Difference Between Arteries, Veins, and Capillaries?

Medically Reviewed by James Beckerman, MD, FACC on February 14, 2024
Written by Stephanie Nicola
3 min read

Your body has a network of blood vessels over 60,000 miles in length. This amazing circulatory system includes three types of blood vessels — arteries, veins, and capillaries. Each plays an important role in carrying blood throughout your body.

Blood vessels are small tube-like structures that transport blood inside your body. How do you know if a blood vessel is an artery, vein, or capillary? Several characteristics can help you distinguish between the three.

  • Location of the blood vessel
  • Size of the wall
  • Direction of the blood flow
  • Oxygen content of the blood
  • Presence of muscle tissue
  • Presence of valves

Arteries carry oxygenated blood away from your heart. They have thick walls and a muscular layer that keeps your blood moving. Arteries can be as wide as a nickel (about two centimeters). They are the largest type of blood vessel in your body.

The aorta is the largest artery in your body. The aorta carries blood from your heart to your organs. Arteries have smaller branches called arterioles. Both arteries and arterioles change in size to maintain your body’s blood pressure level.   

Characteristics of Arteries.

  • Located deep in the muscle
  • Have very thick walls
  • Carry blood from the heart to the organs
  • Carry oxygenated blood (except for the pulmonary artery)
  • Has a thick layer of muscle tissue inside
  • Have no valves (except for the pulmonary artery)

Artery vs Vein. Arteries carry blood away from the heart, and veins carry blood towards the heart. With the exception of pulmonary blood vessels, arteries carry oxygenated blood and veins carry deoxygenated blood. Arteries have thick walls with muscle tissue. Veins have thinner walls and use valves to keep your blood flowing.

Artery vs Capillary. Arteries carry blood from your heart to your organs. Capillaries transport blood between arteries and veins. Arteries are the largest blood vessels with the thickest walls, and capillaries are the smallest. Arteries are only located deep inside your muscles, but capillaries are inside tissues all over your body.

Veins carry deoxygenated blood towards your heart and are often located close to your skin. Veins don’t have a muscular layer like arteries do, so they rely on valves to keep your blood moving. Veins start as tiny blood vessels called venules, which become full-size veins as they come closer to your heart.

Characteristics of Veins.

  • Are located closer to the surface of your body
  • Have thin walls
  • Carry blood towards your heart
  • Carry deoxygenated blood
  • Has a thin layer of muscle tissue inside
  • Contain valves to keep blood flowing

Vein vs Artery. Veins are closer to the surface of your body, and arteries are deep inside your muscles. The walls of a vein are thinner than an artery. Veins carry blood from your organs and towards your heart. Arteries carry blood away from your heart. 

Vein vs Capillary. Veins have thicker walls than capillaries. Veins use valves to transport blood towards the heart, but capillaries don’t have valves. Capillaries diffuse blood and nutrients between veins and arteries through their thin walls.

Capillaries connect your arteries to your veins. Capillaries are the smallest type of blood vessel. They can be as tiny as 5 micrometers, which is less than a third of a hair's width.

A capillary wall is only one cell in thickness. The capillary wall is made of endothelial cells and allows oxygen, nutrients, and waste to pass to and from tissue cells.

Characteristics of Capillaries.

  • Are located inside all tissues
  • Have a very thin wall
  • Carry blood between veins and arteries
  • Carry both oxygenated and deoxygenated blood
  • Don't have muscle tissue
  • Don't have valves

Capillary vs Artery. Capillaries are very narrow blood vessels found throughout your body. Arteries are thick and muscular blood vessels found deep inside your muscles. 

Capillary vs Vein. Both veins and capillaries can sometimes be visible through your skin, but veins are larger and thicker than capillaries. While most veins only carry deoxygenated blood, capillaries can transport both oxygenated and deoxygenated blood. 

Blood vessel disorders include high blood pressure and blood clots. Keep your blood vessels strong with healthy lifestyle choices.

Your arteries, veins, and capillaries form a vital roadmap for your blood’s circulation. Maintaining a healthy lifestyle can keep this 60,000-mile system running smoothly.