In Depth: Heart
The heart is the core of the circulatory system, which supplies the body with oxygen and other important nutrients needed to sustain life. Without it, one would couldn’t exist.
On average, the human heart weighs between six and 11 ounces and beats between 60 to 80 times per minute. It pumps about 2,000 gallons—enough to fill a small above-ground swimming pool—worth of blood through your body every day.
Heart rate is affected by physical fitness, activity, emotions, and other factors. The healthier a heart is, the lower the resting heart rate will be.
Hormones released because of emotions and other stimuli affect the heart rate, which is why the heart was historically associated with emotions.
The heart has three layers. They are the:
- Myocardium: The strongest of the three layers, this is the muscle that contracts to pump blood.
- Epicardum: This thin membrane comprises the outermost layer of the heart.
- 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 veins and arteries.
The heart has a double-pump feature that transports blood away from it and back to it. Oxygenated blood leaves the left side of the heart through the ascending aorta. Blood flowing through the right side of the heart is returning from all over the body before it is sent to the lungs where it receives oxygen.