heart anatomy

Anatomy of a Human Heart

Our heart beats 100,000 times a day, pushing 5,000 gallons of blood, every 24 hours, through our body. It supplies our tissues with oxygen- and nutrient-rich blood and carries waste away. Here, we explain how this incredible organ does this critical work.

The heart is divided into four chambers: two on the right side, and two on the left. Each top chamber is called an atrium and each bottom chamber is referred to as a ventricle. The four categories are called the atrium right, the ventricle right, the atrium left and the ventricle left. Via the atria, which are the smaller chambers, blood enters the heart and is pumped out by the larger ones — the ventricles.


1.Right and left sides of the heart

The right-hand side of the heart pumps blood needing oxygen to the lungs.

This blood goes to the lungs where oxygen is loaded up and sent back to the heart. The oxygen-rich blood reaches the left side of the heart and then pumps it to where it is needed throughout the body.

Blood that supplied the muscles and tissues with its oxygen then returns to the right side of the heart to restart the cycle.

2.Superior & Inferior Vena Cavae

These are the 2 large veins that enter the right side of the heart and bring low-oxygen blood into the right atrium. The superior vena cava carries blood from the head and arms and upper body; the inferior vena cava carries blood from the trunk and legs — the lower body.

3.Pulmonary Veins

The right and left pulmonary veins carry the oxygen-rich blood back into the left atrium from the lungs to the heart.

4.Pulmonary Arteries

The pulmonary arteries of the right and left branch of the main pulmonary trunk. From the right ventricle, the blood which needs oxygen is pumped into them and taken to the lungs where it is loaded with oxygen.


The aorta is the most extensive artery in the body. The blood filled with oxygen is pumped into the aorta by the left ventricle, round the aortic arch, and out into the upper body via the 3 main arteries that branch off the aortic arch and through the descending aorta into the thorax, trunk and lower body.


The valves are a one-way door. There are valves that separate the chambers of the heart. As the heart beats, the valves are opened and blood is pumped from one chamber to another.

The Tricuspid Valve separates the right atrium and the right ventricle. The tricuspid valve allows blood to be pumped back into the right ventricle from the right atrium but prevents its flow back again. Likewise the mitral valve opens into the left ventricle from the left atrium.

The pulmonary valve and the aortic valve are in the right and left ventricles, respectively.

Heart valve disorders occur when the valves either allow blood to leak backward, such as mitral valve regurgitation, or when the valves do not open properly, such as mitral valve stenosis.

7.Coronary Arteries

The heart is just a big muscle that pumps blood around the body. Like all your muscles, your heart needs oxygen to work. This oxygen is brought into the heart by the coronary arteries.

Right and left coronary arteries branch off the aorta — a large main blood vessel that leaves the heart with oxygen-rich blood — so that a good supply of oxygen-rich blood is ensured.

If the coronary arteries are narrowed by fatty deposits in the lining of the arteries ( atherosclerosis), the flow of blood to the heart muscle may be restricted. If the heart muscle doesn’t get enough blood, it doesn’t get enough oxygen to work properly — it’s called ischaemia.

Ischaemia can cause chest pain or angina, often described as a feeling of pressure or tightness in the chest. Angina pain can also be felt in the neck, shoulders, or arms. Angina is often caused by physical activity and usually improves with rest.

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