How does the heart work

The left side of your heart sends that oxygen-rich blood out to the body. The body takes the oxygen out of the blood and uses it in your body's cells. When the cells use the oxygen, they make carbon dioxide and other stuff that gets carried away by the blood.

It's like the blood delivers lunch to the cells and then has to pick up the trash! The returning blood enters the right side of the heart. The right ventricle pumps the blood to the lungs for a little freshening up. In the lungs, carbon dioxide is removed from the blood and sent out of the body when we exhale. What's next? An inhale, of course, and a fresh breath of oxygen that can enter the blood to start the process again.

And remember, it all happens in about a minute! When you go for a checkup, your doctor uses a stethoscope to listen carefully to your heart. A healthy heart makes a lub-dub sound with each beat.

This sound comes from the valves shutting on the blood inside the heart. The first sound the lub happens when the mitral and tricuspid valves close. The next sound the dub happens when the aortic and pulmonary valves close after the blood has been squeezed out of the heart.

Next time you go to the doctor, ask if you can listen to the lub-dub, too. Even though your heart is inside you, there is a cool way to know it's working from the outside. It's your pulse. You can find your pulse by lightly pressing on the skin anywhere there's a large artery running just beneath your skin.

Two good places to find it are on the side of your neck and the inside of your wrist, just below the thumb. You'll know that you've found your pulse when you can feel a small beat under your skin. Each beat is caused by the contraction squeezing of your heart. If you want to find out what your heart rate is, use a watch with a second hand and count how many beats you feel in 1 minute. When you are resting, you will probably feel between 70 and beats per minute.

When you run around a lot, your body needs a lot more oxygen-filled blood. Your heart pumps faster to supply the oxygen-filled blood that your body needs. You may even feel your heart pounding in your chest. 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 coronary arteries. 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.

Related Information Electrical System of the Heart. Normal physiology of the cardiovascular system. In V Fuster et al. Our Housecall e-newsletter will keep you up-to-date on the latest health information. Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. Any use of this site constitutes your agreement to the Terms and Conditions and Privacy Policy linked below.

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Normally your heart will beat between 60 to times per minute. This regular rhythmic beating is dependent upon electrical signals being conducted throughout your heart. There are some conditions which can damage your heart muscle, making it weak and unable to pump as efficiently as before:. There are also conditions - like high blood pressure hypertension - which mean your heart has to work harder.

This is called heart failure because of the failure of your heart to pump blood around the body and work efficiently. Home Illnesses and conditions Heart and blood vessels About the heart Understanding how your heart functions. Understanding how your heart functions. Structure of your heart Your heart is made up of three layers of tissue: epicardium myocardium endocardium.

How does a healthy heart work? What can go wrong? Structure Some people are born with a heart that has not developed properly in the womb before birth - this is called congenital heart disease. Cardiovascular system Problems with your heart and circulation system include: heart attack angina stroke.

Sometimes these diseases are inherited from your family.