Human Heart - Anatomy, Functions and Facts about Heart (2023)

Human Heart

The heart is a muscular structure that is situated in the front of the chest. It pumps blood all through the body in a process called circulation. Apart from the heart, the blood vessels and blood as a unit constitute the cardiovascular system.

Table of Contents

  • Introduction
  • Position
  • Functions of the Human Heart
  • Types of Circulation
  • Structure of the HumanHeart
    • Pericardium
    • Structure of the Heart Wall
    • Chambers of the Heart
    • Blood Vessels
    • Valves
  • Facts about Human Heart
  • Important Questions about the Human Heart
  • Practise Labelling the Human Heart Diagram

Introduction to the Human Heart

The human heart is one of the most important organs responsible for sustaining life. It is a muscular organ with four chambers. The size of the heart is the size of about a clenched fist.

The human heart functions throughout a person’s lifespan and is one of the most robust and hardest working muscles in the human body.

Besides humans, most other animals also possess a heart that pumps blood throughout their bodies. Even invertebrates such as grasshoppers possess a heart like pumping organ, though they do not function the same way a human heart does.

Also Refer:Human Circulatory System

Position of Heart in Human Body

The human heart is located between the lungs in the thoracic cavity, slightly towards the left of the sternum (breastbone). It is derived from the embryonic mesodermal germ layer.

The Function of Heart

The function of the heart in any organism is to maintain a constant flow of blood throughout the body. This replenishes oxygen and circulates nutrients among the cells and tissues.

Following are the main functions of the heart:

  • One of the primary functions of the human heart is to pump blood throughout the body.
  • Blood delivers oxygen, hormones, glucose and other components to various parts of the body, including the human heart.
  • The heart also ensures that adequate blood pressure is maintained in the body

There are two types of circulation within the body, namely pulmonary circulation and systemic circulation.

Human Heart - Anatomy, Functions and Facts about Heart (1)

Pulmonary circulation (blue) and Systemic circulation (red)

(Video) The Human Body: The Heart | Educational Videos For Kids

Types of Circulation

  • Pulmonary circulation is a portion of circulation responsible for carrying deoxygenated blood away from the heart, to the lungs and then bringing oxygenated blood back to the heart.
  • Systemic circulation is another portion of circulation where the oxygenated blood is pumped from the heart to every organ and tissue in the body, and deoxygenated blood comes back again to the heart.

Now, the heart itself is a muscle and therefore, it needs a constant supply of oxygenated blood. This is where another type of circulation comes into play, the coronary circulation.

  • Coronary circulation is an essential portion of the circulation, where oxygenated blood is supplied to the heart. This is important as the heart is responsible for supplying blood throughout the body.
  • Moreover, organs like the brain need a steady flow of fresh, oxygenated blood to ensure functionality.

In a nutshell, the circulatory system plays a vital role in supplying oxygen, and nutrients and removing carbon dioxide and other wastes from the body. Let us gain a deeper insight into the various anatomicalstructures of the heart:

Structure of the HumanHeart

The human heart is about the size of a human fist and is divided into four chambers, namely two ventricles and two atria. The ventricles are the chambers that pump blood and the atrium are the chambers that receive blood. Among these both the right atrium and ventricle make up the “right heart,” and the left atrium and ventricle make up the “left heart.” The structure of the heart also houses the biggest artery in the body – theaorta.

Human Heart - Anatomy, Functions and Facts about Heart (2)

The right and the left region of the heart are separated by a wall of muscle called the septum. The right ventricle pumps the blood to the lungs for re-oxygenation through the pulmonary arteries. The right semilunar valves close and prevent the blood from flowing back into the heart. Then, the oxygenated blood is received by the left atrium from the lungs via the pulmonary veins. Read on to explore more about the structure of the heart.

External Structure of Heart

One of the very first structures which can be observed when the external structure of the heart is viewed is the pericardium.

Pericardium

The human heart is situated to the left of the chest and is enclosed within a fluid-filled cavity described as the pericardial cavity. The walls and lining of the pericardial cavity are made up of a membrane known as the pericardium.

The pericardium is a fibre membrane found as an external covering around the heart. It protects the heart by producing a serous fluid, which serves to lubricate the heart and prevent friction between the surrounding organs. Apart from the lubrication, the pericardium also helps by holding the heart in its position and by maintaining a hollow space for the heart to expand itself when it is full. The pericardium has two exclusive layers—

  • Visceral Layer:Itdirectly covers the outside of the heart.
  • Parietal Layer: Itforms a sac around the outer region of the heart that contains the fluid in the pericardial cavity.

Structure of the Heart Wall

The heart wall is made up of 3 layers, namely:

  • Epicardium – Epicardium is the outermost layer of the heart. It is composed of a thin-layered membrane that serves to lubricate and protect the outer section.
  • Myocardium – This is a layer of muscle tissue and it constitutes the middle layer wall of the heart. It contributes to the thickness and is responsible for the pumping action.
  • Endocardium – It is the innermost layer that lines the inner heart chambers and covers the heart valves. Furthermore, it prevents the blood from sticking to the inner walls, thereby preventing potentially fatal blood clots.

Internal Structure of Heart

The internal structure of the heart is rather intricate with several chambers and valves that control the flow of blood.

(Video) Anatomy of the Heart: Structures and Blood Flow [Cardiology Made Easy]

Chambers of the Heart

Vertebrate hearts can be classified based on the number of chambers present. For instance, most fish have two chambers, and reptiles and amphibians have three chambers. Avian and mammalian hearts consists of four chambers. Humans are mammals; hence, we have four chambers, namely:

  • Left atrium
  • Right atrium
  • Left ventricle
  • Right ventricle

Atria are thin and have less muscular walls and are smaller than ventricles. These are the blood-receiving chambers that are fed by the large veins.

Ventricles are larger and more muscular chambers responsible for pumping and pushing blood out into circulation. These are connected to larger arteries that deliver blood for circulation.

The right ventricle and right atrium are comparatively smaller than the left chambers. The walls consist of fewer muscles compared to the left portion, and the size difference is based on their functions. The blood originating from the right side flows through the pulmonary circulation, while blood arising from the left chambers is pumped throughout the body.

Blood Vessels

In organisms with closed circulatory systems, the blood flows within vessels of varying sizes. All vertebrates, including humans, possess this type of circulation. The external structure of the heart has many blood vessels that form a network, with other major vessels emerging from within the structure. The blood vessels typically comprise the following:

  • Veins supply deoxygenated blood to the heart via inferior and superior vena cava, and it eventually drains into the right atrium.
  • Capillaries are tiny, tube-like vessels which form a network between the arteries to veins.
  • Arteries are muscular-walled tubes mainly involved in supplying oxygenated blood away from the heart to all other parts of the body. Aorta is the largest of the arteries and it branches off into various smaller arteries throughout the body.

Also Refer: Difference between Arteries and Veins

Valves

Valves are flaps of fibrous tissues located in the cardiac chambers between the veins. They ensure that the blood flows in a single direction (unidirectional). Flaps also prevent the blood from flowing backwards. Based on their function, valves are of two types:

  • Atrioventricular valves are between ventricles and atria. The valve between the right ventricle and right atrium is the tricuspid valve, and the one which is found between the left ventricle and left atrium is known as the mitral valve.
  • Semilunar valves are located between the left ventricle and the aorta. It is also found between the pulmonary artery and the right ventricle.

Also Read: Blood and its Composition

Facts about Human Heart

Human Heart - Anatomy, Functions and Facts about Heart (3)

  • The heart pumps around 6,000-7,500 litres of blood in a day throughout the body.
  • The heart is situated at the centre of the chest and points slightly towards the left.
  • On average, the heart beats about 100,000 times a day, i.e., around 3 billion beats in a lifetime.
  • The average male heart weighs around 280 to 340 grams (10 to 12 ounces). In females, it weighs around 230 to 280 grams (8 to 10 ounces).
  • An adult’s heart beats about 60 to 100 times per minute, and a newborn baby’s heart beats at a faster pace than an adult which is about 90 to 190 beats per minute.

Also Refer:Heart Health

To know more about the human heart structure and function, or any other related concepts such as arteries and veins, the internal structure of the heart, and the external structure of the heart,explore BYJU’S Biology. Also, learn aneasy diagram of the heart, concepts and relevant questions for the human heart for Class 10by downloading BYJU’S – The Learning App.

More to Explore:

(Video) The Human Heart | Anatomy and Function of the Human Heart

  • Hypoxia
  • Heart Diseases
  • Hepatic Portal System

Frequently Asked Questions

1. What is pulmonary circulation? Explain.

Pulmonary circulation is a type of blood circulation responsible for carrying deoxygenated blood away from the heart, and to the lungs, where it is oxygenated. The system then brings oxygenated blood back to the heart to be pumped throughout the body.

2. Define systemic circulation.

In systemic circulation, the heart pumps the oxygenated blood through the arteries to every organ and tissue in the body, and then back again to the heart through a system of veins.

3. Elaborate on coronary circulation and its significance.

The heart is a muscle, and it needs a constant supply of oxygenated blood to survive and work effectively. This is where coronary circulation fulfils this function through a network of arteries and veins in the heart. The coronary arteriessupply oxygenated blood to the heart, and thecardiac veins drain the blood once it has been deoxygenated by the tissues of the heart.

4. Briefly explain the structure of the human heart.

The human heart is divided into four chambers, namely two ventricles and two atria. The ventricles are the chambers that pump blood and atrium are the chambers that receive the blood. Among which, the right atrium and ventricle make up the “right portion of the heart”, and the left atrium and ventricle make up the “left portion of the heart.”

5. Name the chambers of the heart.

  • Left atrium
  • Right atrium
  • Left ventricle
  • Right ventricle

6. What is pericardium? Explain its function.

The pericardium is a fibrous membrane that envelops the heart. It also serves a protective function by producing a serous fluid, which lubricates the heart and prevents friction between the surrounding organs. Furthermore, the pericardium also holds the heart in its position and provides a hollow space for the heart to expand and contract.

(Video) HUMAN HEART - Anatomy, Function & Facts about heart

7. Explain the three layers of the heart wall.

The heart wall is made up of 3 layers, namely:

  • Epicardium – This is the outermost layer of the heart. It is composed of a thin layer of membrane that protects and lubricates the outer section.
  • Myocardium – This is a layer of muscle tissue that constitutes the middle layer wall of the heart. It is responsible for the heart’s “pumping” action.
  • Endocardium – The innermost layer that lines the inner heart chambers and covers the heart valves. Prevents blood from sticking, thereby avoiding the formation of fatal blood clots.

8. Explain the three major blood vessels of the human body.

The blood vessels comprise:

  • Veins– It supplies deoxygenated blood to the heart via inferior and superior vena cava, eventually draining into the right atrium.
  • Capillaries– They are minuscule, tube-like vessels which form a network between the arteries and veins.
  • Arteries – These aremuscular-walled tubes responsible for supplying oxygenated blood away from the heart to all other parts of the body.

9. What is the function of the heart valves? Provide examples of various valves.

Valves are flaps of tissues that are present in cardiac chambers between the veins. They prevent the backflow of blood. Examples include the atrioventricular valves, tricuspid valves, mitral valves and the semilunar valves.

10. What is meant by myocardial infarction?

Myocardial infarction is a serious medical condition where the blood flow to the heart is reduced or entirely stopped. This causes oxygen deprivation in the heart muscles, and prolonged deprivation can cause tissues to die.

Label the Heart Diagram below:

Practice your understanding of the heart structure. Drag and drop the correct labels to the boxes with the matching, highlighted structures.

Instructions to use:

  • Hover the mouse over one of the empty boxes.
  • One part in the image gets highlighted.
  • Identify the highlighted part and drag and drop the correct label into the same box.
  • After finishing all the labelling, check your answers.
  • Aorta
  • Left atrium
  • Vena cava
  • Right atrium
  • Semilunar valve
  • Pulmonary artery
  • Right ventricle
  • Left ventricle
  • Pulmonary vein
  • (Video) Human Heart Anatomy | Functions and Facts

    FAQs

    What is the anatomy of the human heart? ›

    The heart is made up of four chambers: two upper chambers known as the left atrium and right atrium and two lower chambers called the left and right ventricles. It is also made up of four valves: the tricuspid, pulmonary, mitral and aortic valves.

    What are the 4 main parts of the heart? ›

    The heart is made up of four chambers. The upper two chambers are called atria (singular: atrium) and the lower two are known as ventricles (singular: ventricle). Muscular walls, called septa or septum, divide the heart into two sides.

    What are the functions of each part of the heart? ›

    The right ventricle passes the blood on to the pulmonary artery, which sends it to the lungs to pick up oxygen. The left atrium receives the now oxygen-rich blood from the lungs and pumps it into the left ventricle. The left ventricle pumps the oxygen-rich blood to the body through a large network of arteries.

    What is the anatomical function of the heart? ›

    Chambers of the Heart

    The heart pumps blood through the network of arteries and veins called the cardiovascular system. The heart has four chambers: The right atrium receives blood from the veins and pumps it to the right ventricle.

    Where exactly is the heart located? ›

    The heart is located between the right and left lungs in the middle of your chest. The heart's function is to supply oxygen and blood to all parts of the body.

    What is the most powerful part of the heart? ›

    The left ventricle is the strongest of your heart's pumps. Its thicker muscles need to perform contractions powerful enough to force the blood to all parts of your body.

    What color is the heart without blood? ›

    The heart will appear white if it has been drained of blood.

    What is the heart made of? ›

    Your heart is made up of three layers of tissue: epicardium. myocardium. endocardium.

    Do you know facts about the heart? ›

    The heart weighs between 9 and 12 ounces (250 and 350 grams). The heart beats about 100,000 times per day (about three billion beats in a lifetime). An adult heart beats about 60 to 80 times per minute. Newborns hearts beat faster than adult hearts, about 70 -190 beats per minute.

    How many main functions does the heart have? ›

    The four main functions of the heart are: Pumping oxygenated blood to other body parts. Pumping hormones and other vital substances to different parts of the body. Receiving deoxygenated blood and carrying metabolic waste products from the body and pumping it to the lungs for oxygenation.

    How many hearts can a human have? ›

    There is just one heart in the human body. Conjoined twins, on the other hand, can be born with two hearts. Humans can only have two hearts if a new one was grafted into an existing one as part of a mandatory surgical procedure.

    Is the heart a Muscle or an organ? ›

    The heart is a fist-sized organ that pumps blood throughout your body. It's the primary organ of your circulatory system. Your heart contains four main sections (chambers) made of muscle and powered by electrical impulses.

    Why do we have 2 sides to your heart? ›

    The right side of your heart receives the de-oxygenated blood that has just travelled round your body. It pumps the blood to your lungs to collect a fresh supply of oxygen. The left side of your heart pumps the re-oxygenated blood round your body again.

    What are the 3 heart walls? ›

    The wall of the heart separates into the following layers: epicardium, myocardium, and endocardium. These three layers of the heart are embryologically equivalent to the three layers of blood vessels: tunica adventitia, tunica media, and tunica intima, respectively.

    What are the most important parts of the heart? ›

    The Heart Valves

    The mitral valve lets oxygen-rich blood from your lungs pass from the left atrium into the left ventricle. The aortic valve opens the way for oxygen-rich blood to pass from the left ventricle into the aorta, your body's largest artery.

    What are the 10 function of heart? ›

    It supplies oxygen and nutrients to the tissues and removes carbon dioxide and waste from the blood. It also helps to maintain adequate blood pressure throughout the body. Heart pumps the blood throughout the body, hence playing an important role in maintaining body temperature.

    What is the function of heart step by step? ›

    The four chambers of the heart work together by alternately contracting and relaxing to pump blood throughout the heart. To accomplish this, the heart uses an electrical system to trigger a heartbeat. Essentially, the electrical system is the power source that makes all the heart's functions possible.

    What organ is under your heart? ›

    Under and around the left breastbone are the heart, spleen, stomach, pancreas, and large intestine. And that's in addition to the left lung, left breast, and left kidney, which actually sits higher in the body than the right one.

    What part of the heart feels pain? ›

    Though similar to angina chest pain, a heart attack is usually a more severe, crushing pain usually in the center or left side of the chest and is not relieved by rest. Sweating, nausea, shortness of breath, or severe weakness may accompany the pain.

    Where does your heart usually hurt? ›

    Chest pain is discomfort or pain that you feel anywhere along the front of your body between your neck and upper abdomen. Symptoms of a possible heart attack include chest pain and pain that radiates down the shoulder and arm. Some people (older adults, people with diabetes, and women) may have little or no chest pain.

    What are the 3 main functions of the heart? ›

    Your heart is the primary organ of your circulatory system. It pumps blood throughout your body, controls your heart rate and maintains blood pressure.

    What is the function of the heart biblically? ›

    In the Bible the heart is considered the seat of life or strength. Hence, it means mind, soul, spirit, or one's entire emotional nature and understanding.

    What do the 4 values of the heart do? ›

    Two of the valves, the mitral and the tricuspid valves, move blood from the upper chambers of the heart (the atria) to the lower chambers of the heart (the ventricles). The other two valves, the aortic and pulmonary valves, move blood to the lungs and the rest of the body through the ventricles.

    What is 10 heart function? ›

    A normal heart pumps blood out of its left ventricle at about 50 to 70 percent — a measurement called an ejection fraction, according to the American Heart Association. “Don was at 10 percent, which is basically a nonfunctional heart,” Dow said. “When a heart is pumping at only 10 percent, a person can die very easily.

    What controls the heart function? ›

    Heart rate is controlled by the two branches of the autonomic (involuntary) nervous system. The sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). The sympathetic nervous system (SNS) releases the hormones (catecholamines - epinephrine and norepinephrine) to accelerate the heart rate.

    What are the 3 main structures of the heart? ›

    The outer layer of the heart wall is the epicardium, the middle layer is the myocardium, and the inner layer is the endocardium.

    What are 2 functions of the heart? ›

    The functions of the heart are to pump blood and oxygen around the body and deliver waste products (carbon dioxide) back to the lungs to be removed. The heart consists of four chambers, each separated by valves which direct the flow of blood.

    Can you function without a heart? ›

    Each cell got all essential nutrients through blood which is pumped by heart. So, without it, no one can live. In serious heart failure patients, a total artificial heart saves the life, but a transplant is necessary. So without heart, survival is not possible.

    What is the power of heart? ›

    Power of heart = work done per second = work done per beat × number of beats in a second =1J×1. 2s−1=1. 2W.

    What Scripture talks about heart? ›

    Proverbs 4:23 – Above all else, guard your heart, for it is the wellspring of life. Proverbs 14:30 – A heart at peace gives life to the body, but envy rots the bones. Proverbs 15:13 – A happy heart makes the face cheerful, but heartache crushes the spirit.

    Which heart function is most important? ›

    It's the muscle at the centre of your circulation system, pumping blood around your body as your heart beats. This blood sends oxygen and nutrients to all parts of your body, and carries away unwanted carbon dioxide and waste products.

    How does a heart work? ›

    Each day, your heart beats around 100,000 times. This continuously pumps about five litres (eight pints) of blood around your body through a network of blood vessels called your circulatory system. This blood delivers oxygen and nutrients to all parts of your body to help your organs and muscles work properly.

    How many arteries are in the heart? ›

    The 2 main coronary arteries are the left main and right coronary arteries.

    What causes heart failure? ›

    Most often, heart failure is caused by another medical condition that damages your heart. This includes coronary heart disease, heart inflammation, high blood pressure, cardiomyopathy, or an irregular heartbeat. Heart failure may not cause symptoms right away.

    How many functions does the heart have? ›

    The four main functions of the heart are: Pumping oxygenated blood to other body parts. Pumping hormones and other vital substances to different parts of the body. Receiving deoxygenated blood and carrying metabolic waste products from the body and pumping it to the lungs for oxygenation.

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