The Heart

What Does the Heart Do?

The heart is a muscle about the size of a closed fist. The heart usually beats about 60–- 80 times per minute. With each beat, your heart pushes blood throughout your body. Blood doesn’t flow on its own; it needs the heart to beat (contract) and push the blood through your blood vessels.

Each time your heart beats, your heart muscle is contracting. You might not think of your heart as a muscle that gets a big workout. But it does. Think about what the heart does every day in a healthy adult:

• It pumps about 1,900 gallons (7,200 liters) of blood.
• It beats 100,000 times.
• And it gets only a fraction of a second to rest between each beat!

The term cardiac refers to the heart. Your heart’s walls are made mostly of strong muscle called the myocardium. The myocardium is the strongest, hardest- working muscle in your body. It has to be—your heart pumps blood from your head to your toes. None of your tissues or organs could survive without the oxygen and nutrients carried by your blood.

Where Is the Heart Located?

Your heart is located slightly to the left of the center of your chest. Your breastbone protects your heart. For further protection, your heart is positioned inside your ribcage, and between your lungs. Although not really shaped like a valentine heart, your heart is slightly pointed at the lower end. The lower end is called the apex.