THE CIRCULATORY SYSTEM
This blood gives our body the oxygen and nutrients it needs. Blood also carries waste that needs to be eliminated from our body.
The heart is an organ made of very strong involuntary muscles.
There are three types of blood vessels: arteries carry blood and nutrients from the heart to all parts of our body. Veins carry blood back to the heart from the rest of our body. Capillaries are very small vessels that connect arteries and veins