Heart Facts

• The heart is made of muscle.
• The blood from the heart carries oxygen to all parts of the body.
• The blood vessels, called arteries, carry the oxygen-rich blood.
• The job of the heart is to pump blood throughout the body.
• The heart needs its own oxygen supply to survive.
• When the heart works hard, it needs a larger supply of oxygen.

The Heart: Chamber and Valves

• The heart has four chambers.
• The atria (upper chambers) receive blood into the heart.
• The ventricles (lower chambers) pump blood out of the heart.
• There are four valves in the heart.
• The valves act as one-way doors to keep the blood flowing in the same path.
• The septum is a wall that divides the heart into right and left sides.

The Heart: Right and Left Sides

• The right side of the heart receives oxygen-poor blood from the body.
• The oxygen-poor blood is then pumped to the lungs.
• While the blood is in the lungs, it picks up a new supply of oxygen.
• The left side of the heart receives oxygen-rich blood from the lungs.
• The oxygen-rich blood is pumped to the body by the left ventricle.
• The aorta carries the oxygen-rich blood out of the heart from the left ventricle.
• The left ventricle does most of the heart's pumping work.

The Heart: Coronary Arteries

• The heart receives its supply of oxygen-rich blood through the coronary arteries.
• The coronary arteries lie on the surface of the heart.