Heart

What and where is it?

The heart is a hollow muscle located in the chest between the lungs, behind the breastbone and tilted slightly to the left, and it is the centre of the circulatory system.

What it does

How it works

1. 1
   The electrical signalBegins in the sinoatrial node, the heart's natural pacemaker.
2. 2
   Contraction of the atriaThey push blood into the ventricles.
3. 3
   ConductionThe signal passes through the atrioventricular node to the ventricles.
4. 4
   Contraction of the ventriclesThe right pumps blood to the lungs and the left to the body, and the valves prevent its backflow.
5. 5
   RelaxationThe heart relaxes and fills again in preparation for the next beat.

The four valves: tricuspid and pulmonary on the right side, mitral and aortic on the left. The heart gets its nourishment from the coronary arteries that branch from the aorta.

Links to other organs

The lungs

• Blood in them exchanges carbon dioxide for oxygen before returning to the left side of the heart.

The kidneys

• They take part in regulating blood pressure and fluid volume, so the heart's function is affected by their health and affects it.

Blood vessels

• Arteries carry blood from the heart, and veins return it to it.

Conditions that affect it

Cardiovascular diseases are among the leading causes of death worldwide according to the World Health Organization.

• Coronary heart diseaseCondition
• Heart failureCondition
• ArrhythmiasCondition
• Heart valve diseaseCondition
• Hypertension (High blood pressure)Condition

Tests used to study it

• ElectrocardiogramProcedure
• EchocardiogramProcedure
• CT scan (computed tomography)Procedure
• MRI scan (magnetic resonance imaging)Procedure
• Lipid profileLab test

Keeping it healthy

• Not smoking or quitting.
• Regular physical activity: 150 to 300 minutes a week of moderate activity for adults.
• A balanced diet low in salt and unhealthy fats.
• Controlling blood pressure, sugar and blood lipids.