It's a muscle in your chest made of four Chambers which are called ...
Right/left atrium (top)
Right/left ventricle (bottom)
The right side pumps blood to the lungs, while the left side pumps it around the body
Arteries branch out into smaller vessels called capillaries where oxygen and nutrients diffuse into cells and wasteproducts diffuse back into the bloodstream.
Blood is pumped from the heart into arteries that carry it away from the heart.
Veins carry deoxygenated blood from the tissues back to the heart
Blood is pumped through arteries by contraction of the heart muscles
Capillaries allow exchange between tissues and blood.
