Breathe. Within seconds, the oxygen you took in is cruising throughout your body.

Oxygen is carried by fast-flowing rivers of blood. What powers that bloodstream? Feel the answer for yourself. Just put your hand on your chest. Beneath the skin and bone lies a thumping, pumping muscle—your heart.

Heart Diagram

Heart Diagram

Left Atrium
Receives oxygen-rich blood from the lungs

Right Atrium
Receives “used” blood from throughout the body

Right Ventricle
Pumps blood to the lungs to pick up oxygen

Left Ventricle
Pumps oxygen-rich blood throughout the body

Amanda Bereny/Selavy Studios (heart chambers)