The heart is a hollow, muscular organ composed of cardiac muscles and connective tissue that acts as a pump to distribute blood throughout the body’s tissues.

The heart is the epicenter of the circulatory system, which supplies the body with oxygen and other important nutrients needed to sustain life.

The heart has three layers. They are the:

  • Epicardium: This thin membrane is the outer-most layer of the heart.
  • Myocardium: This thick layer is the muscle that contracts to pump and propel blood forward.
  • Endocardium: The innermost layer is thin and smooth.

The heart is divided into four chambers: two atria and two ventricles. Blood is transported through the body via a complex network of veins and arteries.

The average human heart weighs between 6 and 11 ounces. The muscle is strong enough to pump up to 2,000 gallons — as much as a fire department’s tanker truck — of blood through one’s body every day.

The average heart beats between 60 and 80 times per minute, but this depends on a person’s cardiovascular health and activity level. The more physically fit people are, the lower their resting heart rates will be.

The body’s reaction to emotions and other stimuli affect the heart rate, which is why the heart was historically thought to be the root of emotions.

Although a broken heart is a favorite topic for poets and songwriters, a truly diseased heart is a serious health concern that can lead to immediate death. Irregular or rapid heartbeats, dizziness, and chest pain are just a few signs of problems. Some common heart conditions include:

  • High blood pressure
  • Heart attack
  • Stroke
  • Congenital heart defects
  • Peripheral artery disease
  • Enlarged heart