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How does your heart work?

How does your heart work?

The human heart is an incredible organ that is about the size of your fist. It beats around 100,000 times every day, sending blood to every part of your body via a network of blood vessels. Blood carries oxygen and nutrition to cells and also takes away carbon dioxide and waste products to be excreted by the lungs and kidneys.

The structure of the heart

Your heart is made up of four chambers with an upper atrium and a lower ventricle on each side. Near the centre of the heart is a small structure, called the sinus node, which is your heart’s natural pacemaker that generates the electrical signals that keep your heartbeat regular.

  • The right side of the heart pumps deoxygenated blood to the lungs.
  • The left side of the heart pumps oxygenated blood from the lungs to the rest of the body.
  • The left and right sides of the heart are separated by a thin muscular wall called the septum.

There are four valves in the heart, which act as gates to keep blood flowing in one direction:

  • the tricuspid valve and the pulmonary valve on the right side of the heart
  • the mitral valve and the aortic valve on the left.

What is heart disease?

The heart is effectively a muscle, and just like every other tissue in the body, it needs a constant supply of oxygen and energy from blood. This is delivered by 2 small arteries - the right and left coronary arteries which branch out to supply all of the heart. 

Heart disease is a broad range of conditions caused by problems with the structure of the heart or conditions that interrupt the supply of blood to the heart muscle.

How can the heart’s blood supply be interrupted?

Narrowing of the coronary arteries can lead to problems like angina or heart attacks. This is caused by a gradual build up of fatty deposits within the walls of coronary arteries. As the arteries narrow, it reduces the amount of blood that can flow through. This means that when the heart beats harder or faster, it might not get as much oxygen as it needs. When the heart muscle is deprived of oxygen, it causes chest pain that we call angina. If the coronary arteries get completely blocked by a fatty deposits or clots, it damages the muscle and leads to a heart attack.


What risk factors increase my chances of getting heart and circulatory disease?

Many heart and circulatory diseases share the same risk factors including:

  • raised blood pressure
  • raised cholesterol
  • being overweight or obese
  • poorly managed diabetes
  • smoking
  • drinking too much alcohol.

Making lifestyle changes to tackle these risk factors can significantly reduce your chances of having angina or a heart attack. A mediterranean style diet, regular physical activity, getting to a healthy weight and looking after your physical and mental health will all help you reduce your risk of cardiovascular disease.

Posted by Dr Kingshuk Pal
The advice we are providing is as accurate and as comprehensive as possible, but it is only general advice and should not be used as a substitute for the individual advice you might receive from consulting your qualified medical practitioner. Please ensure you consult a qualified medical professional before making any changes to your healthcare.