The heart is at the center of your circulatory system, which is a
network of blood vessels that delivers blood to every part of your body. Blood
carries oxygen and other important nutrients that all body organs need to stay
healthy and to work properly.
Your heart is a muscle, and its job is to pump blood throughout your
How does my heart pump blood?
Your heart is divided into two separate pumping systems, the right
side and the left side.
The right side of your heart receives
oxygen-poor blood from your veins and pumps it to your lungs, where it picks up
oxygen and gets rid of carbon dioxide.
The left side of your heart
receives oxygen-rich blood from your lungs and pumps it through your arteries
to the rest of your body.
The right atrium receives oxygen-poor blood
from the body and pumps it to the right ventricle through the tricuspid
The right ventricle pumps the oxygen-poor blood to the lungs
through the pulmonary valve.
The left atrium receives oxygen-rich
blood from the lungs and pumps it to the left ventricle through the mitral
The left ventricle pumps the oxygen-rich blood through the
aortic valve out to the rest of the body.
The left and right atria are smaller chambers that pump blood into
the ventricles. The left and right ventricles are stronger pumps. The left
ventricle is the strongest because it has to pump blood out to the entire body.
When your heart functions normally, all four chambers work together in a
continuous and coordinated effort to keep oxygen-rich blood circulating
throughout your body. Your heart has its own electrical system that coordinates
the work of the heart chambers (heart rhythm) and also controls the frequency
of beats (heart rate).
How does my heart maintain its normal function?
The task of your heart is to pump enough blood to deliver a
continuous supply of oxygen and other nutrients to the brain and the other
vital organs. To do this, your heart needs to:
Regulate the timing of your heartbeat. Your heart's
electrical system controls the timing of the pump. The
electrical system keeps your heart beating in a regular rhythm and adjusts the
rate at which it beats. When the electrical system is working properly, it
maintains a normal heart rate and rhythm. Problems with this electrical system
can cause an arrhythmia, which means that your heart chambers are beating in an
uncoordinated or random way or that your heart is beating too fast
(tachycardia) or too slow (bradycardia).
Keep your heart muscle healthy. The four chambers of your heart are made of a
special type of muscle called myocardium. The myocardium does the main pumping
work: It relaxes to fill with blood and then squeezes (contracts) to pump the
blood. "Contractility" describes how well the heart muscle squeezes. After
pumping, your heart relaxes and fills with blood. The muscle must be able to
relax enough so that it can fill with blood properly before it pumps again. The
health of your heart muscle affects both its contractility and its ability to
relax, both of which determine whether your heart is able to pump enough blood
each time it beats. Problems with the contractility of your heart can be caused
by problems with the muscle itself (such as a viral infection of the heart
muscle or an inherited heart muscle disorder) or by problems with the blood
supply to the heart muscle (such as reduced blood flow to the heart muscle,
called ischemia). Your heart muscle needs its own supply of blood because, like
the rest of your body, it needs oxygen and other nutrients to stay healthy. For
this reason, your heart pumps oxygen-rich blood to its own muscle through your
Keep blood flowing efficiently. Your heart has four valves that control the flow of blood
in and out of the chambers. There are valves between the atrium and the
ventricle on each side of your heart. There is also a valve controlling the
flow of blood out of each of your ventricles. The valves are designed to keep
blood flowing forward only. When each chamber contracts, a valve opens to allow
blood to flow out. When the chamber relaxes, the valve closes to prevent blood
from leaking back into the chamber and to allow the chamber to fill with blood
again. A problem with your heart valves can disrupt the normal flow of blood
and cause problems for your heart.
How this information was developed to help you make better health decisions.