The heart is a strong, fist-sized muscle that keeps blood moving through the lungs and the rest of the body. Most people know it as the organ that keeps us alive, but far fewer know where it sits, how it is built, and why each chamber matters.

That basic understanding becomes useful very quickly. The moment someone is told they have a valve problem, heart failure, a murmur, or blocked arteries, they start hearing terms such as atrium, ventricle, septum, and myocardium. A simple explanation of heart anatomy makes those conversations far easier to follow.

The heart is not placed entirely on the left side. It sits in the middle of the chest, between the lungs, with a slight tilt towards the left. From there, it works without pause, adjusting its pace to sleep, exercise, stress, illness, and recovery.

What is the heart?

People often search simple phrases such as what is heart or heart meaning when they want a clear explanation. In basic terms, the heart functions as a muscular pump. Its job is to receive blood returning from the body, send that blood to the lungs for oxygen, receive oxygen-rich blood back from the lungs, and then pump it out to the rest of the body.

In simple terms, the heart maintains the flow of circulation. Without that constant flow, the brain, kidneys, liver, muscles, and other organs cannot get the oxygen and nutrients they need.

Where in the body is the heart situated?

If you have ever wondered which side the heart is on, the honest answer is this: it is centrally placed, but more of it lies towards the left side of the chest. People also search for the heart location in the body and the heart position in the human body when they want to understand where the organ actually sits. It lies behind the breastbone, between the lungs, and above the diaphragm.

The lower pointed end, called the apex, angles towards the left. That is why the heartbeat is often felt more clearly on the left side.

Parts of the heart

The heart consists of four chambers. The right atrium and left atrium are the two upper chambers. The two lower chambers of the heart are the right ventricle and the left ventricle.

The right side receives blood returning from the body and pumps it to the lungs. The left side of the heart receives oxygenated blood from the lungs and distributes it throughout the body.

Between the chambers are valves that keep blood moving in the correct direction. These include the tricuspid valve, pulmonary valve, mitral valve, and aortic valve.

Internal structure of the heart

The heart's internal structure consists of chambers that are divided by a wall known as the septum. This prevents oxygen-poor and oxygen-rich blood from mixing under normal circumstances.

Large blood vessels are attached to the heart. The venae cavae transport blood from the body to the right atrium. The pulmonary artery transports blood to the lungs. The pulmonary veins transport oxygenated blood back to the left atrium. The aorta transports blood from the left ventricle to the rest of the body.

The heart receives its own blood supply via the coronary arteries. These vessels nourish the heart muscle itself.

Layers of the heart

The inner layer is referred to as the endocardium, while the middle layer, which is thick and muscular, is known as the myocardium. The outer covering is often discussed as the epicardium, while the surrounding protective sac is the pericardium.

Of these layers, the myocardium does most of the pumping work. It is especially thick in the left ventricle because that chamber has to push blood through the whole body.

How the heart works

Blood that is low in oxygen flows into the right atrium, travels to the right ventricle, and is then pumped to the lungs. After picking up oxygen, it returns to the left atrium, passes into the left ventricle, and is then pumped through the aorta to the rest of the body.

This cycle happens again and again. Electrical signals within the heart coordinate the beat so the chambers contract in an organised sequence rather than all at once.

Why understanding heart structure matters

Patients often hear words such as enlarged heart, valve leak, reduced ejection fraction, septal defect, or left ventricular dysfunction. These terms make much more sense when you already understand the structure of the heart.

It also helps people recognise why symptoms differ. A valve problem may lead to breathlessness, an electrical problem may cause palpitations, and a blocked artery may cause chest pain.

When to consult a doctor

Medical advice is important if there is chest pain, unexplained breathlessness, palpitations, fainting, swelling in the legs, or a strong family history of heart disease.

Even if symptoms appear to be mild, it's important to pay attention to ongoing changes, particularly in those who have diabetes, high blood pressure, high cholesterol, or a history of smoking.

How Narayana Health can help

Narayana Health offers cardiac consultations, diagnostic testing, preventive screening, and specialist-led care for a wide range of heart conditions.

A consultation can help patients understand not just what has been found, but what part of the heart is involved and what that means for treatment.