Hundreds of years ago, ancient civilizations believed that emotions derive from the heart. Recent science is of the belief system that emotions derive in the brain, and the brain tells the heart whether to speed up or slow down.
According to KidsHealth.org, the heart is a muscle, about the size of an adult fist, and is located slightly to the left of the midline of the chest. While the heart is like the other 649 muscles in the body, it is also quite unique. The heart circulates oxygenated blood to the rest of the body, as well as carries away waste.
The left and right sides of the heart have two different functions: While the right side of the heart receives blood and sends it to the lungs for oxygenation, the left side of the heart sends the oxygenated blood to the rest of the body.
The heart beats by contracting once it fills with blood. The heart pumps all day and night for the entirety of someone’s life and has the ability to beat over three billion times. For this reason, the heart is considered the hardest working muscle in the body.
For more about the heart, its function and how it works, read the rest of the article here.