Your heart is a pump that keeps blood moving around your body. It delivers oxygen and nutrients to all parts of your body, and carries away unwanted carbon dioxide and waste products.

The structure of the heart: The heart is made up of three layers

Pericardium – thin outer protective sack
Myocardium – specialised cells making up the thick muscular wall
Endocardium – thin inner lining of the heart

Inside the heart there are four chambers – two on the left side and two on the right

The two small upper chambers are called the atria
The two larger lower chambers are called the ventricles

The left and right sides of the heart are divided by a muscular wall called the septum. There are four valves in your heart. They act like ‘gates’ that open and close, making sure that your blood travels in one direction through your heart – a bit like a one-way traffic system. They are called the tricuspid valve and the pulmonary valve on the right side of the heart, and the mitral valve and the aortic valve on the left. Like every other living tissue, the heart itself needs a continuous supply of fresh blood. This blood supply comes from the coronary arteries which branch off from the main artery (the aorta) as it leaves the left ventricle. The coronary arteries spread across the outside of the myocardium, supplying it with blood.

How blood travels around your body: As your heart muscle contracts, it pushes blood through your heart. With each contraction, or heartbeat:

Your heart pumps blood forward from its left side, through the aorta (the main artery leaving the heart) and into the arteries. Blood from the right side is pumped to your lungs.
The blood continues through the arteries, which divide off into smaller and smaller branches of microscopic capillaries.Travelling through this network of capillaries, blood reaches every part of your body.
The blood then travels back to the heart from the capillaries into the veins. The branches of the veins join to form larger veins, which deliver the blood back to the right side of your heart.

As the heart relaxes in between each heartbeat or contraction, blood from your veins fills the right side of your heart and blood from the lungs fills the left side of your heart. The two sides of the heart are separate, but they work together. The right side of the heart receives dark, de-oxygenated blood which has circulated around your body. It pumps this to your lungs, where it picks up a fresh supply of oxygen and becomes bright red again.

The cardiovascular system: This movement of blood around the body, pumped by the heart, is called circulation. This system is called the cardiovascular system (or heart and circulatory system).

It contains about five litres (eight pints) of blood, which your heart is continuously circulating.
Each day, your heart beats about 100,000 times.
It pumps about 23,000 litres (5,000 gallons) of blood around your body.

For your heart to keep pumping regularly, it needs an electrical supply. This is provided by a special group of heart cells called the sinus node, which is also known as your heart’s natural pacemaker.

Symptoms: Disease of the heart and circulation is an umbrella term for several types of conditions including heart attacks, stroke and disturbance to your hearts rhythm. The symptoms you might experience will vary depending on the type of disease.

Heart attack symptoms: It's important to remember that the symptoms of a heart attack can vary from one person to another. Symptoms can range from a severe pain in the centre of the chest, to having mild chest discomfort that makes you feel generally unwell. In some cases, chest pain or discomfort are accompanied by other symptoms. If you, or anyone around you, experience any of these symptoms, don't ignore them. This means that you will get treatment as soon as possible. The sooner you get treatment, the greater your chances of survival.

Symptoms include:

central chest pain; a dull pain, ache or 'heavy' feeling in your chest; or a mild discomfort in your chest that makes you feel generally unwell. The pain or discomfort may feel like a bad episode of indigestion
this pain or discomfort may spread to the arms, neck, jaw, back or stomach as well as having chest pain or discomfort you can feel light-headed or dizzy and short of breath
You may also feel nauseous or vomit

Tests for your heart: There are many different tests to find how how your heart is doing or to diagnose a condition.

What to expect? If you have a heart condition, or are suspected of having one, there are a number of tests your doctor may use. Some of the tests involve high-tech equipment with lots of machines, wires and computer screens, which may feel very impersonal. These range from physical assessments to MRI scans. It's normal to feel a bit nervous if you are sent for a test, so knowing what to expect may help you feel more at ease. Our website explains what all these tests are for and how they are done. A healthcare professional can explain these tests to you as well. If you feel uneasy, remember that it often helps to get fears out into the open, so tell the people doing the tests how you feel.They can then explain things to you again and try to reassure you. It can also help if your partner, relative or friend goes along with you for support and help during or after the test. For some tests they may be able to sit with you, but for others they will have to wait outside or in the hospital. And, if you speak to the doctor after the test, it’s good to have someone by your side who can help understand and reassure you.

Conditions: If you or a loved one have been diagnosed with a heart problem, you may be feeling worried, overwhelmed or anxious. Sometimes, understanding your heart problem and knowing the facts can help you come to terms with it and help you to feel less worried.

What is heart disease? Heart disease is a term used to describe a number of different heart conditions and problems. These include Angina, Heart Failure and Abnormal heart rhythms as well as many others, If you're at all worried that you may have a heart problem you should speak to your doctor.

Am I at risk? There are a number of thing that can increase your risk of getting a heart problem, such as diabetes and high cholesterol.

Treatment: Finding out that you or a loved one has a problem with their heart can be frightening, but there are very effective treatments available which help to get people better and improve their quality of life. Information about the various treatments can be complex and difficult to understand.

Prevention: There's lots you can do to keep your heart healthy - whatever your age. Taking exercise, eating a healthy diet, encouraging children to be heart healthy and being aware of dangers such as smoking, drinking, high blood pressure and stress. Prevention really is better than cure.

Why? Prevention is as relevant to people who already have heart disease as it is for everyone else. In every case it's all about getting the balance right. People of all ages who are physically active are half as likely to get cardiovascular disease as those that are inactive.And a healthy diet helps to reduce your risk of developing heart disease, or if you've already got heart problems it will help to protect your heart.

Am I at risk? We should all be thinking about our heart health and what we can do to keep as healthy as possible.

Recovery: Leaving hospital , When you've been diagnosed with a heart condition it's natural to need time to come to terms with what has happened to you and how your everyday life may be affected.