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Heart

7-minute read

If you are concerned about your heart, see your doctor. If you suspect you may be having a heart attack, call triple zero (000) and ask for an ambulance.

Key facts

  • The heart is a muscular organ that sits inside the rib cage, behind and to the left of the sternum (breastbone).
  • The heart pumps blood around the body to supply tissues with nutrition and oxygen.
  • The heart is made up of outer muscular walls, chambers, valves, arteries and veins and the electrical conduction system.
  • You can lower your heart disease risk with regular exercise, maintaining a healthy weight, reducing stress, eating well and quitting smoking.

What is the heart?

The heart is a muscular organ that sits inside the rib cage, behind and to the left of the breastbone. It pumps blood around the body to supply tissues with nutrition and oxygen.

What is the function of the heart?

The function of the heart is to pump blood around your body to supply tissues (body cells) with nutrition and oxygen. The heart pumps blood to the lungs, where it take in oxygen. This oxygen-rich blood then returns to the heart to be pumped to the rest of the body via arteries. The heart delivers blood to its own muscular tissue via the coronary arteries.

What are the different parts of the heart?

The parts of the heart include:

  • the outer muscle (myocardium)
  • 4 chambers (2 atria and 2 ventricles)
  • valves
  • arteries and veins
  • the electrical conduction system

The major artery coming from the heart is the aorta.

The muscle of your heart contracts and relaxes to pump blood around your body. The muscle is divided into 3 layers:

  • the endocardium (inner layer)
  • the myocardium (middle layer)
  • the epicardium (protective outer layer)

The heart has 4 chambers. The upper chambers are the right and left atria, the lower chambers are the right and left ventricles. The heart is divided into 2 sides (the right and left sides) by a thin wall called the septum.

There are 4 valves that act like doors between the different chambers of your heart.

  • The atrioventricular (AV) valves act as the doors between the atria and the ventricles.
  • The semilunar valves act as the doors between the ventricles and the major blood vessels leaving the ventricles.

Blood is pumped to the heart, lungs and around the body via blood vessels. There are 3 types of blood vessels:

  • arteries — carry oxygenated blood to from the heart to the body
  • veins — carry deoxygenated blood from the body back to the heart and lungs
  • capillaries — small vessels where oxygenated and deoxygenated blood is exchanged

Your heart is kept beating by the heart’s electrical system.

How does the heart work?

This is how the heart pumps blood:

  1. The upper chambers of the heart, the right and left atria, receive blood.
  2. The blood then flows through valves into the right or left ventricle to be pumped to the lungs or body.
    1. Heart valves stop the blood flowing backwards. When the valves shut, they create a sound that can be heard with a stethoscope.
  3. Deoxygenated blood from the right ventricle then flows through the pulmonary artery to the lungs where the blood becomes oxygenated.
  4. Oxygenated blood from the left ventricle flows through the aorta to the rest of your body.

Electrical pathways in the heart muscle make it pump. The heart’s pacemaker cells automatically trigger heartbeats. The heart muscle then squeezes, causing blood to move.

Illustration showing how the blood flows in the human heart.
Illustration showing how the blood flows in the human heart.

What medical conditions are related to the heart?

There are many different health conditions related to the heart — here are a few:

  • Angina is chest pain caused when an area of heart muscle is not getting enough blood. Discomfort can spread to the shoulder, neck or jaw.
  • Coronary artery disease occurs when the coronary arteries become clogged with fatty deposits.
  • A heart attack (myocardial infarction) occurs when a blockage in a coronary artery reduces the blood (and oxygen) supply to heart muscle.
  • Heart failure occurs when the heart pumps less effectively, potentially causing tiredness, shortness of breath and sometimes swelling in the legs.
  • Heart valve disease occurs when the valves do not open or close properly, causing problems with blood flow.
  • Arrhythmias occurs when the heart is not beating in the usual pattern. The beat can be irregular, too fast or too slow.

ARE YOU AT RISK? — Are you at risk of type 2 diabetes, heart disease or kidney disease? Use the Risk Checker to find out.

How can I take care of my heart?

You can lower your heart disease risk by:

It is also important to manage your blood pressure and blood cholesterol level, and — if you have diabetes — to manage your blood sugar levels.

The things you do to keep your heart healthy can also help protect you from other diseases, such as type 2 diabetes and kidney disease.

Infographic showing 6 ways to take care of your heart
6 ways to take care of your heart

Resources and support

For more information about how your heart works, heart conditions and how to keep your heart healthy, visit:

Read more on heart health in a range of community languages on the Heart foundation website.

Visit the St Vincents Hospital NSW and Heart Foundation Aboriginal heart health website for information for Aboriginal and/or Torres Strait islander people.

You can also call healthdirect on 1800 022 222 at any time to speak to a registered nurse (known as NURSE-ON-CALL in Victoria) for more information and advice.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: October 2023


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