Understanding Heart: it’s Shape, Structure and Functions - Medx Health Assistance

Understanding Heart: it’s Shape, Structure and Functions

The heart beats roughly 115,000 times every day. Going with the facts, the heart can continue beating even when it’s uncoupled from the body. The heart is a muscular organ located just behind and slightly left of the breastbone. Measuring to a closed fist, the heart is a full-time worker, pumping blood via the network of blood vessels called arteries and veins. Together, the heart, blood vessels and the blood make up the cardiovascular system. 

The heart gains its nutrients and oxygen through the coronary arteries that travel along the heart’s surface, which is also richly distributed by a web of nerve tissue that facilitates the rhythmic heartbeat; it often conducts the complex signals that govern contraction and relaxation. A heart wall is formed by three layers: the outer layer is the epicardium, the middle one is the myocardium and the inner layer is the endocardium. The heart is surrounded by a fluid-filled sac named pericardium. Being a protective covering, the pericardium produces fluid that lubricates the heart and avoids friction between the heart and the neighbouring organs. 


A human heart has four chambers. The upper two chambers are known as the atria, whereas the lower two chambers are called the ventricles. The right atrium and right ventricle are referred to as the right heart, the left atrium and left ventricle are referred to as the left heart. 

Functions of the chambers of the heart:

  • The right atrium collects deoxygenated blood from the body and pumps it to the right ventricle. 
  • The right ventricle receives blood from the right atrium and pumps it to the lungs, where it is filled with oxygen. 
  • The left atrium draws and pumps oxygenated blood from the lungs to the left ventricle.
  • The left ventricle is one of the strongest chambers of the heart that pumps blood which is rich in oxygen to the rest of the body. Its vigorous contractions form one’s blood pressure.

heart | Structure, Function, & Facts | Britannica


The heart propels blood through two different circuits. Venous blood from the head, chest and arms is received in the right atrium through a large vein called the superior vena cava whereas blood from the abdomen, pelvic region, and legs is received through the inferior vena cava. Then the blood passes through the tricuspid valve to the right ventricle which further pushes it through the pulmonary artery to the lungs. Here this venous blood is oxygenated by coming in contact with the inhaled air. Now the oxygenated blood returns through the pulmonary veins to the left atrium. This is called pulmonary circulation.

Valves of the heart:

The flow of blood into the heart, from the heart and within the heart chambers is protected by the four valves present in the heart. A human heart can’t work normally if the heart valves aren’t functioning properly, since it can affect the flow of the blood via the heart. Pumps require a set of valves to maintain the fluid flowing in one direction and the heart is no exception. The heart has two kinds of valves that keep the blood flowing in the right direction and help maintain the required pressure. 

  • The valves between the atria and ventricles are known as atrioventricular valves, it’s also called cuspid valves. And those at the bases of the large vessels leaving the ventricles are known as semilunar valves. The right atrioventricular valve is referred as the tricuspid valve. The left atrioventricular valve is the bicuspid valve. 
  • The pulmonary semilunar valve is the valve between the right ventricle and pulmonary trunk and the valve between the left ventricle and the aorta is the aortic semilunar valve. 

To prevent the blood from flowing back into the atria, atrioventricular valves close when the ventricles shrink. Similarly, to prevent the blood from flowing back into the ventricles, semilunar valves close while the ventricles rest.

Functions of the heart:

The heart is the prime organ in the circulatory system. The heart structure is primarily responsible for transferring the blood and transportation of nutrients in all parts of the body. This non-stop task uplifts the heart’s role as an essential organ whose normal operation is constantly necessary. Blood passing through the left atrium, bicuspid valve, left ventricle, aorta, tissues of the body, and back to the right atrium constitutes the systemic circulation. Blood pressure is maximum in the left ventricle and in the aorta and its arterial branches. It is reduced in the capillaries and is reduced further in the veins carrying blood back to the right atrium. Around 5.6 litres of blood circulates in the body.

Summarizing the main functions of the heart:

  • The heart receives deoxygenated blood and carries metabolic waste products from the body and pumps it to the lungs for oxygenation.
  • It pumps oxygenated blood to the other parts of the body.
  • It pumps hormones and other vital substances to different parts of the body.
  • It maintains blood pressure.


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