Human Heart

All living things need energy for various metabolic activities, movement, and locomotion, but the most important part is the distribution of nutrients throughout the human body that is performed by the blood vessels. However, a single organ is responsible for the proper working of the blood vessels by maintaining the blood flow inside them, which is the Heart. The primary function of the human heart is to pump the blood throughout the whole body that is from head to toe and is responsible for the gaseous exchanges that take place throughout the body tissues and cells.

Structure and Location

The Human heart is about the size of a clenched fist and is enclosed in a double membrane called the pericardium. The fluid inside the pericardium is the pericardial fluid. The double membrane acts as a lubricant and supportive barrier for the strong muscles of the heart and keeps it in place.

Furthermore, the human heart is formed of four chambers. The two anterior chambers that produce and receive blood are called the auricles, and the posterior chambers that distribute blood are called the ventricles. The walls of the right ventricle anatomy are stronger because blood is pumped out at great pressure. Between these chambers, door-like valves are present that maintain the flow of blood in a single direction from the auricles to the ventricle. The valves prevent the reverse flow of blood.

Different Valves related to the Heart

Four major valves are related to the heart:

• Right Auriculo-ventricular Valve: This valve is also known as the Tricuspid valve. It is present between the right auricle and the right ventricle.

• Left Auriculo-ventricular Valve: This valve is also known as the Mitral or Bicuspid valve and is situated between the left auricle and the left ventricle.

• Pulmonary Semilunar Valve: This valve is located at the opening of the pulmonary artery in the right ventricle.

• Aortic Semilunar Valve: This valve is located at the opening of the aorta in the left ventricle.

NOTE: These valves are anchored to the walls of the ventricles by a thread-like band of tissues called the chordae tendineae.

Working of the Heart

To understand about human heart working process, we have divided this segment into the following steps:

• STEP-1: Deoxygenated blood is brought by the vena cava into the right auricle.

• STEP-2: This deoxygenated blood is poured into the right ventricle from the right auricle and is sent to the lungs for oxygenation.

• STEP-3: Oxygenated blood brought from the lungs is poured into the left auricle

NOTE: The circulation of blood from the right ventricle of the heart to the lungs and then back to the heart in the left auricle is known as pulmonary circulation.

• STEP-4: Oxygenated blood is forced into the left ventricle.

• Step-5: All the oxygenated blood is supplied throughout the body from the left ventricle.

The Heartbeat

In the heart cycle of human beings, two sounds can be heard. These sounds are:

• LUB: This sound represents the onset of the ventricular systole. This sound is produced when the mitral and tricuspid atrioventricular close.

• DUB: This sound marks the relaxation of the ventricles, also known as ventricular diastole. This sound is produced when the pulmonary or aortic valves close.

Both these tones produce a rhythmic sound called a heartbeat that can be heard through an instrument known as the stethoscope. In a healthy adult, the normal heart rate of the human body on average is 72 beats per minute, but this can vary from 60-80 beats per minute. During exercise, the heart beats faster to distribute more blood throughout the muscles and prevents the muscles from getting fatigued.

NOTE: Sometimes, the specialised muscle cells responsible for initiating a heartbeat stop functioning, resulting in the abnormal beating of the heart. Thus, a device called a ‘pacemaker’, also called the sinoatrial node, is put in place of those muscles which work fluently and maintain the normal heart rate of the body.

A detailed structure of the heart contains the following components:

1. Superior Vena Cava: This vein is responsible for bringing deoxygenated blood from the upper parts of the body, which are the head, nose, eyes, neck, etc.
2. Inferior Vena Cava: This vein is responsible for bringing deoxygenated blood against gravity from the extreme lower parts of the body, which are the toes, feet, legs, etc. 
3. Aorta: This is the body’s main artery responsible for carrying oxygenated blood throughout the body.
4. Pulmonary Artery: This artery carries deoxygenated blood from the heart to the lungs.
5. Pulmonary Vein: This vein carries oxygenated blood from the lungs to the heart.
6. Septum: These walls divide the left and right sides of the human heart. The right and left atria are separated by the interatrial septum whereas the interventricular septum separates the left and right ventricles.

Heart Diseases

Several diseases are concerned with the human heart:

• Hypertension: It is a condition in which the force of blood against the heart of walls is too high. Systolic pressure reading should be more than 140 mm of Hg, and Diastolic reading should be less than 90 mm. 

• Symptoms: Fatigue, headaches, nosebleed, vision problem.

• Causes: Physical inactivity, high salt diets, consumption of junk food.

• Prevention: Healthy diet, regular exercise, avoiding alcohol and drugs.

• Cardiac Arrest: It is a sudden stop of the flow of blood due to failure of the heart to contract effectively. 

• Symptoms: Fainting, blackouts, chest pain, shortness of breath.

• Causes: Major blood loss, very low potassium levels, heart failure, lack of oxygen.

• Prevention: Healthy diet, regular exercise, avoid smoking, no to alcohol and drugs.

Conclusion

The human heart is of the primary importance in the human body as it is responsible for the fluent working of the circulatory system of the human body. Four chambers are responsible for purifying blood and facilitating the flow of blood to the extreme parts of the body. To prevent heart diseases, we should adhere to a healthy diet and lifestyle, as well as exercise regularly.