Fascinating Facts About Your Heart:

The heart is a unique organ that has components of both muscle and nervous tissue. As a component of the cardiovascular system, its job is to pump blood to the cells and tissues of the body. Did you know that your heart can continue to beat even if it is not in your body? Discover 10 fascinating facts about your heart.

1. YOUR HEART BEATS AROUND 100,000 TIMES IN A YEAR

In young adults, the heart beats between 70 (at rest) and 200 (heavy exercise) times per minute. In one year, the heart beats around 100,000 times. In 70 years, your heart will beat more than 2.5 billion times.

2. YOUR HEART PUMPS ABOUT 1.3 GALLONS OF BLOOD IN ONE MINUTE

When at rest, the heart can pump approximately 1.3 gallons (5 quarts) of blood per minute. Blood circulates through the entire system of blood vessels in only 20 seconds. In a day, the heart pumps around 2,000 gallons of blood through thousands of miles of blood vessels.

3. YOUR HEART STARTS BEATING BETWEEN 3 AND 4 WEEKS AFTER CONCEPTION

The human heart starts to beat a few weeks after fertilization takes place. At 4 weeks, the heart beats between 105 and 120 times per minute.

4. COUPLES' HEARTS BEAT AS ONE

A University of California at Davis study has shown that couples breath at the same rate and have synchronized heartbeats. In the study, couples were connected to heart rate and respiration monitors as they went through several exercises without touching or speaking to each other. The couples' heart and breathing rates tended to be synchronized, indicating that romantically involved couples are linked on a physiological level.

5. YOUR HEART CAN STILL BEAT APART FROM YOUR BODY

Unlike other muscles, heart contractions are not regulated by the brain. Electrical impulses generated by heart nodes cause your heart to beat. As long as it has enough energy and oxygen, your heart will continue to beat even outside of your body.

The human heart may continue to beat for up to a minute after removal from the body. However, the heart of an individual addicted to a drug, such as cocaine, can beat for a much longer period of time outside of the body. Cocaine causes the heart to work harder as it reduces blood flow to the coronary arteries that supply blood to the heart muscle. This drug increases heart rate, heart size, and can cause heart muscle cells to beat erratically.

6. HEART SOUNDS ARE MADE BY HEART VALVES

The heart beats as a result of cardiac conduction, which is the generation of electrical impulses that cause the heart to contract. As the atria and ventricles contract, the closing of the heart valves produces the "lub-dupp" sounds. 

A heart murmur is an abnormal sound caused by turbulent blood flow in the heart. The most common type of heart murmur is caused by problems with the mitral valve located between the left atrium and left ventricle. The abnormal sound is produced by the backflow of blood into the left atrium. Normal functioning valves prevent blood from flowing backward.

7. BLOOD TYPE IS LINKED TO HEART DISEASE

Researchers have found that your blood type could put you at a higher risk of developing heart disease. According to a study published in the journal Arteriosclerosis, Thrombosis and Vascular Biology, those with blood type AB have the highest risk for developing heart disease. Those with blood type B have the next highest risk, followed by type A. Those with blood type O have the lowest risk. The reasons for the link between blood type and heart disease are not fully understood; however, type AB blood has been linked to inflammation and type A to increased levels of a certain type of cholesterol.

8. ABOUT 20% OF CARDIAC OUTPUT GOES TO THE KIDNEYS AND 15% TO THE BRAIN

About 20% of blood flow goes to the kidneys. The kidneys filter toxins from the blood which are excreted in urine. They filter about 200 quarts of blood per day. Consistent blood flow to the brain is necessary for survival. If blood flow is interrupted, brain cells can die within a matter of minutes. The heart itself receives about 5% of cardiac output through the coronary arteries.

9. A LOW CARDIAC INDEX IS LINKED TO BRAIN AGING

The amount of blood pumped by the heart is linked to brain aging. People who have a low cardiac index have a smaller brain volume than those with a high cardiac index. Cardiac index is the measure of the amount of blood that pumps from the heart in relation to a person's body size. As we get older, our brain shrinks in size normally. According to a Boston University study, those with low cardiac indexes have almost two years more brain aging than those with high cardiac indexes.

10. SLOW BLOOD FLOW CAN CAUSE HEART DISEASE

Researchers from the University of Washington have uncovered more clues as to how heart arteries may become blocked over time. By studying blood vessel walls, it was discovered that blood cells move closer together when they are in areas where blood flow is swift. This clinging together of cells reduces the loss of fluid from blood vessels. The researchers noted that in areas where blood flow is slow, there tends to be more leakage from arteries. This leads to artery-blocking cholesterol buildup in those areas.