Heart ( The Symphony Within ) / Function And Disorders

Heart ( The Symphony Within ) / Function And Disorders

Table of Contents


The heart is a muscle in the body, and its activity is part of the blood circulation system, where blood is pumped to all the tissues and organs of the body. In fact, the heart is the driving force in the body.

The heart beats about 100,000 times a day and pumps about 8 pints of blood in the body every 24 hours. This work brings the blood rich in oxygen and nutrients to the textures and organs and carries the waste materials with it.

This organ is located in a two-layer serous bag called the pericardium.

Its function is to send deoxygenated blood to the lungs, where the blood is augmented with oxygen and carbon dioxide, and metabolic waste is discharged. The heart, blood, and blood vessels, which include arteries, veins, and capillaries, all together make up the circulatory system.

What is the heart?

This small but powerful organ is the command center of blood flow in the body. The center of pumping blood to the whole body is located between the lungs and in the middle of the chest, leaning to the left side of the sternum, just below the stomach.

Due to the proximity of the stomach and heart, sometimes stomach pains are confused with cardiovascular problems.

The structure of the heart is such that it takes blood out of the heart through the vascular network and enters the head and neck, abdomen, upper and lower limbs.

The average weight of the heart in men aged 31 to 40 is 6.289 grams and in women of the same age range, 7.284 grams, and in the ages of 61 to 70 years, the average weight of the heart is 9.345 grams in men and 1.285 grams in women.

The length, width, and thickness of the human heart are about 12 cm, 5.8 cm, and 6 cm, respectively.

To better understand the function and anatomy of the heart in the body, we must first examine some important concepts, which are:

Pre-cardiac systems

  • blood circulation

    Blood circulation in the body is an extraordinary and continuous strategy in which the heart, blood vessels, and various organs have regular and related cooperation. The circulatory system is divided into two main circuits: systemic circulation and pulmonary circulation.

    1. Pulmonary circulation

Deoxygenated blood enters the heart. The heart pumps it to the lungs through the pulmonary arteries.

The lungs take in oxygen and deliver carbon dioxide through the process of gas exchange. Oxygenated blood reverts to the heart via the pulmonary veins.

    1. Systemic circulation:

The blood, which has been oxygenated in a process by the lungs, returns to the heart from the lungs through the pulmonary veins.

The heart pumps this oxygenated blood through its various valves and delivers it to the various organs and tissues of the body through the aorta and its branches.

In the other part of this cycle, the blood that has given its oxygen to the parts of the body returns to the heart and starts the cycle again.

Blood, as an essential liquid for the body with a regular flow, transports gases, delivers nutrients to the organs, removes waste products from the body, regulates pH and electrolyte balance, and defends and supports the immune system in cooperation with the cardiovascular system.

Now that you are familiar with the concept of blood circulation in the body, it is better to get acquainted with the colleagues of blood circulation in the body.

  • Associates of the circulatory system

    • proof of order in the world

      The circulatory system, also known as the cardiovascular system, is an extraordinary and exciting network of cooperating organs, vessels, and fluids.

This system is a coordinated cooperation of the members that ensures the proper circulation of blood in the body. The main components of this admirable system are:

      1. Heart:

The heart is a muscular organ. This organ is known as the driving force of blood; with the action of contraction and expansion, it causes blood to be pumped to the organs and its constant movement. 

The heart can also be considered as a blood refueling station.

As we said before, one of the functions of blood is to supply oxygen to organs. 

Therefore, when the blood gives the oxygen in it to the organs and becomes deoxygenated, it returns to the heart. Then, the heart gives it to the organs that have the task of providing oxygen (lungs). 

Then he takes it back from them and gives it to the organs again.

      1. Blood vessels

Arteries: This organ transports oxygenated blood from the heart to the tissues and organs of the body.

Systemic veins: The blood that has given its oxygen to the organs returns to the heart through the veins.

pulmonary veins: The blood that has been oxygenated by the lungs returns to the heart through the pulmonary veins to be pumped to the organs.

Capillaries: These tiny vessels with thin walls are a path to deliver oxygen and brain substances in the blood to the organs and also a path to return waste materials from the organs to the blood to leave the body.

      1. Blood:

a mysterious liquid that is constantly moving in the cardiovascular system and contains different parts. These are include:

      •   Red blood cells (RBC) are responsible for delivering oxygen from the lungs to body tissues and returning carbon dioxide to the lungs for elimination.
      • White blood cells (WBCs): These are the body’s defense forces and part of the immune system.
      • Platelets: They function to prevent blood loss in the body by clotting blood.
      • Plasma: These are actually carriers of nutrients from the blood to the organs and waste materials from the organs to the blood.


Well, now that we understand what blood circulation in the body is and which organs are responsible for blood circulation, it is time to address the main topic, which is the heart and its function. First is the function of the heart.

Related: “WBC Count: A Guide To Understanding Your Results And Next Steps

The structure of the heart

The heart is located in the center of the chest (between the lungs), between the second and fifth ribs.

Because it is surrounded by the chest, it is relatively protected from all kinds of injuries.

The heart consists of 4 chambers, several valves, and several layers

It regulates the normal flow of blood in the body, which we will categorize below.

  • Cavities of the heart structure

    • Right Atrium:

      It receives deoxygenated blood from the body and then pumps it to the right ventricle.

    • Right, Ventricle:

      It pumps oxygen-poor blood to the lungs.

    • Left Atrium:

      It catches oxygenated blood from the lungs and pumps it to the left ventricle.

    • Left Ventricle:

      It is the largest and most powerful cavity of the heart.

This cavity pumps oxygen-rich blood through the aorta to the

It circulates through the arteries and capillaries of the body and delivers oxygen to all cells.

The left ventricle has enough muscle strength to push blood out of the heart through the aortic valve.



Blood is pumped through the contraction and expansion of the muscles of each chamber.

Note: You may also have a question as to why there are two numbers from each of the atrium and the ventricle, or what is the reason for the existence of the ventricle and the atrium together? 

In answer to this question, we must say that the existence of this quadruple system is necessary to produce sufficient energy to pump to all organs. And if there is a violation in any of these four parts, the energy of the heart is not enough to drive blood throughout the circulatory system.

  • Valves of the heart structure

    Pumps need a set of valves to keep blood flowing in one direction. In fact, the valves prevent blood from returning to the pumping organ.

The heart has four types of valves that keep blood flowing in the right direction:

    • Aortic valve:

      It is contracted between the left ventricle and the aorta.

    • Pulmonary Valve:

      It is contracted between the right ventricle and the pulmonary artery.

    • Tricuspid Valve:

      It is contracted between the right atrium and the right ventricle.

    • Mitral Valve:

      The atrioventricular valve is the left ventricle. Among the valves of the heart, only this valve has two edges.

Blood trills from the right atrium into the right ventricle per the tricuspid valve.

It flows from the left atrium to the left ventricle through the mitral valve.

Then, when the right ventricle is filled with blood, the tricuspid valve closes.

Prevent blood from reverting to the right atrium.

When the left ventricle is filled with blood, the mitral valve is blocked to prevent blood from flowing back into the atrium.

When the right ventricle shrinks, the pulmonary valve opens

Blood from the right ventricle enters the vein and is transported to the lungs.

When the left ventricle shrinks, the aortic valve opens to allow blood to exit the left ventricle.



Valves ensure one-way blood flow and prevent blood backflow. They act like gates that open and close, ensuring that your blood moves in one direction, a bit like a one-way traffic system.

  • The layers of the heart structure wall

    The heart also has a wall that consists of three layers:

    • Pericardium – a thin outer covering that protects and surrounds your heart.
    • Myocardium – is a thick middle layer of muscle that contracts and pumps blood out of your heart.
    • Endocardium – thin inner lining.

Read this and you will understand all the previous ones

How does the heart work?

As mentioned, the heart has two separate halves that work in perfect harmony with each other.

The right side of the human heart

The right side of the heart receives blood containing carbon dioxide and sends it to the lungs:

The right atrium receives oxygen-deficient or low-oxygen blood through vessels called the superior and inferior vena cava. These veins are the largest veins in the body.

The right atrium contracts, and through a valve called tricuspid, blood is transferred to the right ventricle.

After filling, the right ventricle contracts and pumps blood through the pulmonary artery (through the pulmonary valves) to the lungs. In the lungs, the blood catches oxygen and discharges carbon dioxide.

The left side of the human heart

The left side of the heart catches blood from the lungs and pumps it to the rest of the body:

Fresh oxygenated blood returns to the left atrium through the mitral valve and through the pulmonary veins.

The left atrium contracts and pushes blood into the left ventricle.

After filling, the left ventricle contracts and sends blood out of the heart through the aorta.



The left and right ventricles are stronger pumps than the atria, of which the left ventricle is more powerful because it has to send blood to all parts of the body with suitable pressure.

All these parts, with continuous and coordinated effort and cooperation, try to perform this operation correctly so that the heart function is performed correctly, the blood containing oxygen reaches all parts of the body correctly, and the heartbeat and frequencies are controlled.

The electrical system of the heart

To pump blood throughout the body, the heart muscles must work in concert to pump blood in the right direction, at the right time, and with the right force. Electrical pulses coordinate this activity.

The electrical signal begins at the sinoatrial node, sometimes called the sinus node or SA. This node is the pacemaker of the heart and is located above the right atrium. 

The signal of this node causes the contraction of the atria and pushes the blood into the ventricles.

The electrical impulse then proceeds to an area of cells at the bottom of the right atrium, among the atria and ventricles, called the AV node.

These cells act as gatekeepers. They attune the signal so that the atria and ventricles do not contract simultaneously. There should be some delay.

The signal proceeds along fibers called Purkinje fibers within the walls of the ventricles. The fibers transmit the pulse to the heart muscle and cause the ventricles to contract.

Regular heart rhythm

The overall process of the heart consists of two stages:

  • Systole: a short period that occurs with the closing of the tricuspid and mitral valves; It means when the heart is contracting.
  • Diastole: It is a relatively long period when the aortic and pulmonary valves are closed; It means when the heart is expanding.


In measuring blood pressure, the figures obtained from systole and diastole of the heart are used.

  • Systolic pressure

    It shows how much pressure the blood exerts on the artery wall during systole.

  • Diastolic pressure

    It shows the pressure in the veins during diastole.


The heart is essential for life. If the heartbeat stops, blood does not reach the brain and other organs, and the person may die within minutes. This condition is called cardiac arrest.

If a person has a cardiac arrest, they are no longer able to speak or breathe and have no heartbeat.

In general, if the heartbeat stops:

In about 4-6 minutes without blood flow, brain cells begin to die and

After 10 minutes without blood flow, brain cells fail and die.

Types of heart diseases

One of the most important causes of human mortality is heart disease. These dangerous diseases can seriously affect a person’s life. 

Heart diseases are called diseases that lead to defects or problems in the functioning of the heart and heart vessels. Heart diseases have a wide spectrum.

But in general, heart disease refers to a group of problems, most of which are related to a process called “atherosclerosis.”

Atherosclerosis occurs when fatty deposits (plaque) build up in the walls of arteries. The formation of these plaques narrows the blood vessels and makes it hard for blood to flow through them. 

With the formation of a blood clot at the narrowed point, the blood flow is completely cut off. We call this a stroke that may happen in the brain or heart.

In the following, we introduce the most common cardiovascular diseases:

  1. Heart attack

One of the most common heart diseases is heart attack. Coronary, as the main artery of the heart, is responsible for supplying blood to the heart. 

When fat and cholesterol collect in the arteries, it leads to vascular disorders, the closing of the arteries, and the organization of blood clots in the heart, which leads to a heart attack.

A stroke or heart attack occurs when the blood flow in a part of the heart is interrupted due to the formation of a clot. If this interruption of blood flow occurs completely, the part of the heart muscle provided by that artery begins to die.

Most people who have a heart attack for the first time return to their normal lives and enjoy many years of productive life. However, experiencing a heart attack means that we need to make changes in our lifestyle.

  1. Heart failure

Heart failure, sometimes called congestive heart failure, This disorder, which manifests itself with symptoms such as weight gain and edema means that the heart is not pumping blood as well as it should. 

Heart failure means a decrease in the contractile power of the heart. In this condition, the heart continues to work, but it due to some reason cannot meet the body’s oxygen needs.

Although there are surgical and non-surgical treatments, heart failure gets worse over time if left untreated.

  1. Heart arrhythmia (Arrhythmia)

This condition is called a heart rhythm disorder, which causes improper heart pulses to beat irregularly, mildly, or severely. Irregular heartbeats should be taken seriously and can lead to death if neglected.

 This disease manifests itself with symptoms such as shortness of breath, high sweating, fast and slow heart rate, dizziness, chest pain, and unconsciousness.

  1. Heart valvular diseases

When the heart valves do not open wide enough, and as a result, blood does not pass through them normally, a condition called valvular stenosis occurs.

When the heart valve does not close normally, blood leaks through the valve, which is called regurgitation.

Valve prolapse is a situation in which the valve leaflets (the members that make up the heart valve, which are normally two on the left side and three on the right side) protrude towards the chamber above the part where the valve is located.

    • Mitral valve stenosis

The mitral valve (Mitral valve blockage) is one of the main valves of the heart that controls the transfer of blood between the chambers of the heart. When the blood flow to the left ventricle is disturbed, the blood supply decreases and causes mitral valve stenosis. 

If this condition is not treated in time, it can lead to serious complications. Symptoms of mitral valve stenosis are as follows: shortness of breath, excessive fatigue, heart palpitations, swollen feet, severe and chronic cough, chest pain, fainting, or severe dizziness.

    • Stenosis of the aortic valve of the heart

In aortic stenosis heart disease, the opening of the aortic valve is very narrow and restricts the flow of blood from the left ventricle to the aorta. 

It can also affect the pressure in the left atrium. Some people consider this disease as the worst type of congenital heart disease, but with timely diagnosis and proper treatment, its risks will be eliminated.

The most common cause of aortic stenosis in young people is a congenital defect in which the aortic valve has only two leaflets instead of three leaflets. It is called a bicuspid aortic valve. Aortic stenosis in elderly people (begins after 60 years) is caused by the formation of ulcers and calcium accumulation on the edge of the aortic valve.

Many people with aortic stenosis do not experience significant symptoms until the amount of blood flow is greatly reduced.

  1. Congenital Heart Defect

Structural problems that exist in a baby since birth are known as congenital heart diseases, which are one of the most common complications in the field of heart disease. 

This disease, which often occurs in the first trimester of the mother’s pregnancy, is followed by an abnormality in the structure or function of the heart. This disease is most often diagnosed by a cardiologist during the mother’s pregnancy or after birth. 

Congenital heart defects are known as three main types of heart wall defects: obstruction defects and cyanotic heart defects. Babies with heart disease have persistent and rapid breathing, shortness of breath, purple color on the lips or nails, poor and poor feeding, poor or low body weight index, and lung infections.

  1. Angina

This disease is called pain, which occurs due to a reduce in blood flow to the heart muscle. With this reduction in blood supply, the heart needs more oxygen when working, which eventually leads to a feeling of heaviness or chest pain.

Pain, feeling of pressure and burning in the chest, pain in the arm, neck, chin, shoulder, and even back, nausea, fatigue, shortness of breath, and sweating are common symptoms of angina.

In order to diagnose each of these diseases and find the right treatment for them, the presence of a good cardiologist is considered the main and fundamental step. 

  1. Arteriosclerosis

Arteriosclerosis is the most common disease that affects the structure of the heart.

Coronary artery disease (CAD) is the hardening of the arteries that store oxygen in the heart muscle.

This process is a significant cause of death and disease worldwide.

What factors cause heart problems and your circulatory system not working correctly?

With the narrowing of the arteries, heart and circulatory system problems such as heart attack, angina, and stroke occur. This is caused by the gradual accumulation of fatty substances (called atheroma) in the walls of blood vessels. 

Over time, your arteries can become so clogged that they cannot give enough blood to your heart or brain, which can cause heart attacks, strokes, and vascular dementia.


What puts me at risk for cardiovascular disease?

Many cardiovascular diseases have the same risk factors, as follows:


In uncovering the secrets of the heart, its function, structure, and potential problems – you will gain a deep understanding of the role of this vital organ. In this valuable article for you as the symphony conductor of your life, the intricate design of the heart and the potential challenges you may face are explored.

The good news is that by learning from this article, you now hold the key to cultivating a heart-healthy lifestyle. From appreciating the rhythm of your heart’s dance to recognizing potential issues, your conscious choices can shape a resilient cardiovascular future.

As you move in the song of life, may your heart beat strong and steady and guide a harmonious and healthy existence.

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Author and specialist

Dr. Majid Zahrabi,


  • Board Certified Neurosurgeon
  • DHA certificate holder
  • Plantation certificate holder, France
  • Certified holder of Discogol, France
  • A pioneer in the non-surgical treatment of disc herniation in the Middle East and CIS countries.
  • Under the training and coaching of Professor Jacques Theron (founder of Discogel Therapy) since 2008
  • More than 400 successful cervical and 1300 lumbar discogel injections
  • Trained and certified several neurosurgeons and spine surgeons in the Middle East and CIS countries for the treatment of Discogel
  • Strong belief in patient-centered care planning and participation
  • Neurosurgeon and spine surgeon at Imam Khomeini and Amir Mazandarani Hospital, Sari, Iran, with more than 430 surgeries annually, 2000-2011
  • Neurosurgeon and spine surgeon at Farmaniyeh, Nikan and Yas Sepid Hospital, Tehran, Iran, with more than 400 surgeries annually, 2011-2012
  • Neurosurgeon at Iranian Hospital, Dubai, 2022-2023
  • Since 2015, he has been working as a reference doctor for the treatment of intervertebral disc herniation with Discogel and has trained many doctors of spine-related specialties in various countries of the Middle East and CIS in person/practically and online.



  • Individual training sessions under the direct supervision of Professor Jacques Theron in Discogel treatment, 2008-2020
  • Training sessions under the supervision of Professor Thierry Boye on spinal implants, 2007
  • Participation and presentation in several national and international medical and neuro-spinal conferences
  • Board certificate by Iran Neurosurgery Board, 2001
  • Neurosurgery assistant training course, Isfahan University of Medical Sciences, Isfahan, Iran, 1996-2001 (In 2001, he graduated from Isfahan University of Medical Sciences with the first rank in the country.
  • His thesis the titled:The Application of human amniotic membrane in repair of dura matter in dogs.” ( It was happening for the first time in the world. )
  • General medical education, Tabriz University of Medical Sciences, Tabriz, Iran, 1984-1993


Published books:

  • CT scan of the brain for doctors
  • Etiology and treatment of painful spine disorders
  • Atlas of diagnosis, prevention, and treatment of spine disorders
  • The most common mistakes in the treatment of spinal disorders
  • Reading brain CT scan in simple language (3rd place in the book of the year)
  • Treatment of head and spine injuries

Publications and articles:

  • Bacteriostatic and bactericidal effects of DISCOGEL® (https://www.researchgate.net/)
  • Muscle recovery, reduction of pain, and improvement of movement strategies in patients with lumbar discopathy after injection of Discogel.
  • The article on the initial results of the treatment of intervertebral disc herniation with discogel injection, which won the second-best poster rank at the Pan Arab International Congress of Interventional Radiology (March 14-16, 2015) and was accepted for presentation at the Chicago Pain Congress.
  • The use of human amniotic membrane in dura mater repair in dogs, a study for the first time in the world.



  • Annual Congress of Physiotherapists of Iran, 2019
  • Chicago International Pain Congress, 2019
  • Iran International Pain Management Congress, 2018
  • Annual Congress of Physiotherapists of Iran, 2018
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Armenia for orthopedic specialists and neurosurgeons, 2017
  • First Live Workshop and Seminar on Minimally Invasive Disc Therapy (DISCON), 2017
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Azerbaijan for orthopedic specialists and neurosurgeons, 2016
  • Seminar of Iranian official managers, 2016
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Tajikistan for orthopedic specialists and neurosurgeons, 2016
  • International Neurological Intervention Congress in Iran, 2014
  • Educational seminar for nurses on treatment approaches for head and spine trauma, 2014
  • Educational seminar for general practitioners on treatment approaches for head and spine trauma, 2014
  • Speech at the Retraining Seminar for General Practitioners and Specialists in Dubai (Discon) in 2017
  • Speech in the internal retraining courses of Irani Hospital, Dubai
  • Holding lecture sessions and practical workshops on the treatment of intervertebral disc herniation with discogel injection in Azerbaijan, Tajikistan, Ukraine, Oman, and Armenia during the years 2015 to 2021.
  • Giving a lecture and holding a practical workshop for neurosurgeons in Vietnam at Ho Chi Minh City University in 2023

Dr. Majid Zohrabi started treating his patients in Dubai in 2022 and continues his activities in private medical centers in the UAE.