The Circulatory System

The circulatory system is made of your heart and blood vessels. It is like a highway for blood. Your heart pumps blood all day and all night. The blood brings food and oxygen to every part of your body.

The Heart

Your heart is a muscle about the size of your fist. It sits in the middle of your chest, slightly to the left. It beats around 100,000 times every day. Each beat pushes blood through your body.

A drawing showing the heart and the paths that blood takes.
A drawing showing the heart and the paths that blood takes. (OpenStax College / Wikimedia Commons)

Blood Vessels

Blood travels through tubes called blood vessels. Arteries carry blood away from the heart. Veins bring blood back to the heart. Tiny vessels called capillaries connect them and feed your cells.

Fun Facts

  • If you lined up all your blood vessels, they would go around the Earth twice.
  • Your heart pumps about 2,000 gallons of blood each day.
  • A kid's heart beats faster than a grown-up's heart.

Did You Know?

Your heart keeps beating even when you are sleeping. It never takes a break for your whole life.