Blood
Vessels that carry blood away from the heart
arteries
The heart has 4 of these to close off the blood flow
valves
Humans breathe this out
carbon dioxide
Blood cells that keep people healthy
white
There are 4 of these in the heart
chambers
Why does the heart beat faster when a person works out?
The muscles require more oxygen
Blood delivers this to cells
oxygen
How can a person keep his or her heart healthy?
eat fruits and vegetables, work out, avoid soft drinks and smoking
What is the main purpose of platelets?
To clot blood when a person is cut
Red blood cells: Carry oxygen
White blood cells: ?
destroy bacteria and viruses