Your Heart and its Valves
The heart – the hardest working muscle in the human body –
even works when we're at rest! Located almost in the center of the
chest, the adult human heart is about the size of a fist. At an average
rate of 80 times a minute, the heart beats about 115,000 times in one
day or about 42 million times in a year. Its job is to pump blood filled
with oxygen and nutrients through our blood vessels to the tissues throughout
our body, creating the cardiovascular system.
The heart is made of:
Four chambers (two atria and two ventricles) that receive blue (deoxygenated)
blood from the body and pump out red (oxygen-rich) blood back to it:
- The atria receive blood coming back to the heart.
- The ventricles pump the blood out of the heart.
- Blood vessels, which include a network of arteries and veins that carry
blood throughout the body: Arteries transport blood from the heart to
the body tissues. Veins carry blood back to the heart.
- An electrical system that serves as a natural pacemaker and stimulates
contraction of the heart muscle.
- Mitral Valve – Controls flows of oxygen rich blood from the left
atrium to the left ventricle.
- Tricuspid Valve – Controls flow of oxygen poor blood from the right
atrium to the right ventricle.
- Aortic Valve – Controls flow of oxygen rich blood from the left ventricle
to the body.
- Pulmonary Valve – Controls flow of oxygen poor blood from the right
ventricle to the lungs.
Healthy heart valves assure blood will flow smoothly through the heart
in one direction. When a valve fails to close completely, blood is allowed
to flow in the reverse direction. This is called regurgitation or insufficiency.
Valves can also be narrowed by deposits of calcium; this is called stenosis.
Like any pump, if the valves fail, the pump must work harder to do its
job. Since the heart is a muscle, it can enlarge to compensate for a diseased
valve, but only up to a point before permanent damage and heart failure set in.