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Skip directly to site content Skip directly to page options Skip directly to A-Z link. Section Navigation. Facebook Twitter LinkedIn Syndicate. How the Heart Works. Minus Related Pages. Normal Heart. Information For…. 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.
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 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. It is a muscle that pumps blood to all parts of your body.
The blood pumped by your heart provides your body with the oxygen and nutrients it needs to function.
Your heart is about the size of a clenched fist, and weighs between and g. It lies in the middle of your chest, behind and slightly to the left of your breastbone.
If you are of average body weight and size, your body contains about five litres of blood, all of which passes through your heart every minute or so.
However, when necessary, such as during exercise, your heart can pump up to four times that amount per minute. Your heart has a right and left side separated by a wall called the septum. There are four chambers: the left atrium and right atrium upper chambers , and the left ventricle and right ventricle lower chambers.
The right side of your heart collects blood on its return from the rest of our body. The blood entering the right side of your heart is low in oxygen. Your heart pumps the blood from the right side of your heart to your lungs so it can receive more oxygen. Once it has received oxygen, the blood returns directly to the left side of your heart, which then pumps it out again to all parts of your body through an artery called the aorta.
Blood pressure refers to the amount of force the pumping blood exerts on arterial walls. Each atrium is connected to its ventricle by a one-way valve. The valve on the right side of the heart is called the tricuspid valve, while the valve on the left side is called the mitral valve.
The familiar 'lub-dub' sound of the heartbeat is caused by the rhythmic closing of the heart valves as blood is pumped in and out of the chambers. The heart rate is regulated by a special cluster of cells situated in the right atrium, called the sinus node. This prompts the atria to contract first; then an electrical impulse is sent to a second node the atrioventricular node , which is found between the atria and the ventricles. After a brief delay, the ventricles contract.
At rest, your heart beats approximately 60 to times a minute. This page has been produced in consultation with and approved by:.
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