Blood

Blood is a very important liquid in your body. It travels through your veins and arteries. Blood carries oxygen, food, and other things your body needs. It also carries away waste your body does not want.

What Blood Is Made Of

Blood has four main parts. Red blood cells carry oxygen and give blood its red color. White blood cells fight germs and keep you healthy. Platelets help stop bleeding when you get a cut, and plasma is the liquid part.

A colorful model of the part of blood that carries oxygen.
A colorful model of the part of blood that carries oxygen. (Zephyris at English Wikipedia / Wikimedia Commons)

Why Blood Is Important

Your blood brings food and oxygen to every cell in your body. It also keeps you warm by moving heat around. When you get hurt, blood rushes to help heal you. Your body has about one gallon of blood in it.

Fun Facts

  • One drop of blood has millions of red blood cells.
  • Blood makes up about 7 percent of your body weight.
  • Red blood cells live for about four months.

Did You Know?

People have different blood types like A, B, AB, and O. Doctors need to know your type before giving you new blood.