How it works
The heart is about the size of the fist. It beats about 3 billion times in the average lifespan. Its job is to pump blood through your body. Your job is to keep it healthy.
Blood is a liquid that flows through your body. Your blood travels through thousands of miles of blood vessels. Your blood carries water, oxygen, nutrients, and waste products. your blood also has solids in it. A young person has a gallon of blood, and an adult has 5 quarts.
- Red cells carry oxygen and carbon dioxide. Did you know there are about 5,000,000 red cells in one drop of blood
- White blood cells help the body fight of germs
- Platelets help you stop bleeding
- Plasma is the liquid part of your blood made in your liver