About the Heart and Blood Vessels
About the heart:
The heart is the hardest working muscle in the human body. Located almost in the center of the chest, the heart of a child is about the size of his/her fist. By the age of 70 years old, the human heart will beat more than 2.5 billion times. The heart is always working, 24 hours a day, seven days a week - even while we are sleeping, and pumps about 2,000 gallons of blood daily.
A child's heart works just as hard as an adult's heart. In fact, at rest, a baby's heart may beat up to 140 times a minute, while an adult's heart usually beats between 60 and 100 times a minute. The rate at which the heart pumps gradually slows down from birth to adolescence.
The cardiovascular system, composed of the heart and blood vessels, is responsible for circulating blood throughout the body. A healthy cardiovascular system is vital to supplying the body with oxygen and nutrients.
How the heart works:
The heart is a large, hollow, muscular organ that pumps blood filled with oxygen and nutrients through the blood vessels to the body tissues. It is made up of:
- four chambers (two atria and two ventricles) that receive blood from the body (the atria) and pump out blood to it (the ventricles).
- The right atrium receives blood from the body, which is high in oxygen and low in carbon dioxide.
- The right ventricle pumps the blood from the right atrium into the lungs to provide it with oxygen and remove carbon dioxide.
- The left atrium receives blood from the lungs, which is rich in oxygen.
- The left ventricle pumps the blood from the left atrium into the body, supplying all organs with blood.
- four valves to prevent backward flow of blood: the aortic, pulmonary, mitral, and tricuspid valves. Each valve is designed to allow the forward flow of blood and prevent the backward flow.
- blood vessels that bring blood to the lungs, where oxygen enters the bloodstream, and then to the body.
- The inferior and superior vena cava bring oxygen-poor (blue) blood from the body into the right atrium.
- The pulmonary artery channels oxygen-poor (blue) blood from the right ventricle into the lungs, where oxygen enters the bloodstream.
- The pulmonary veins bring oxygen-rich (red) blood to the left atrium.
- The aorta channels oxygen-rich (red) blood to the body.
- An electrical system stimulates contraction of the heart muscle.
A network of arteries and veins also carry blood throughout the body.
- Arteries transport blood from the heart to the body tissues.
- Veins carry blood back to the heart.
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Disclaimer - This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional evaluation, advice, diagnosis or treatment by a healthcare professional. © 2009 Staywell Custom Communications.