The heart in our body acts as a pump which drives blood into and through the arteries, but the right and left side of the heart of function quiet separately from one another. Blood from all parts of the body is collected and gets poured into the right atrium. The arteries carry the venous blood to the lungs where the inter change of gases takes place, carbon dioxide is excreted and oxygen is absorbed. Thus the hurt works as pumping station in our body.

What is the heart?

The heart is a hollow muscular, cone-shaped organ that supplies blood and oxygen to all parts of the body. The average human heart, beating at 72 beats per minute, will beat approximately 2.5 billion times during an average 66 year lifespan. It weighs approximately 250 to 300 grams in females and 300 to 350 grams in males. The heart measure about 10 cm long and is about the size of the owner's first.

Where is it located?

The heart is located in the chest cavity just posterior to the breastbone, between the lungs and superior to the diaphragm. It tilts obliquely, a little more to the left than the right and presents a circular base above and an apex below. It is usually located on the level of the fifth intercostals space about 9-10 cm from the midline.

Anatomy of Heart

The heart is surrounded by a fluid filled sac called the pericardium. The walls of the heart are made up of three layers while the cavity is divided into four chambers. The two upper chambers are called the right and left atria, and two lower chambers are called the right and left ventricles. The right and left sides of the heart are separated by a muscular partition called as the septum. The two sides of the heart have no communication with each other. Each side is subdivided into an upper and lower chamber. The upper chamber called the auricle or atrium is the receiving chamber into which blood flows through veins. The lower chamber called the ventricle is the discharging chamber from which the blood is driven into the arteries. The major artery of the body is the aorta and the major veins of the body are the vena cavae.

Each atrium communicates with the ventricles below it on the same side of the heart through an opening, guarded by a valve called as the artrio-ventricular valve. The valves ensure blood flow in one direction only- from the upper chamber or atrium to the lower chamber or ventricle. The valve separating the right atrium from the right ventricle is known as the right artrio- ventricular valve (tricuspid valve) and is made up of three flaps or cusps. Similarly the valve separating the left atrium from the left ventricle is called as the left artrio-ventricular valve (mitral valve) and is composed of two flaps of cusps. The valve between the artria and the ventricles open and close as a result of changes in the pressure of blood within the chambers. Also the valves are prevented from opening upwards by the tendinous cords, which originate in the papillary muscles in the walls of the ventricle.

Functions of Heart

The function of the heart is to maintain a constant circulation of blood throughout the body. It pumps the blood, which carries all the vital materials which help our bodies function and removes the waste products that we do not need. For example, the brain requires oxygen and glucose, which, if not received continuously, will cause it to loose consciousness. Muscles need oxygen, glucose and amino acids, as well as the proper ratio of sodium, calcium and potassium salts in order to contract normally.

The heart acts as a pump which drives blood into and through the arteries, but the right and left side of the heart of function quiet separately from one another. Blood from all parts of the body is collected and gets poured into the right atrium through the two largest veins of the body, the superior and inferior venacavae. When it gets filled, the right atrium contracts and drives the blood through the right artrio-ventricular valve into the right ventricle, which is turn contracts sending the blood through the pulmonary valve and into the pulmonary artery. The pulmonary artery passes through the walls of the heart and divides into left and right pulmonary artery. These arteries carry the venous blood to the lungs where the inter change of gases takes place, carbon dioxide is excreted and oxygen is absorbed.

The arterial or oxygenated blood is collected from each lung by four pulmonary veins, which empty their content into the left atrium of the heart. This oxygenated blood passes through the left artrio ventricular valve into the left ventricle from where it is pumped into the aorta, the main artery of the body to all parts of the body. Both the openings of the pulmonary artery and the aorta are also guarded by valves as pulmonary and aortic valves respectively.

These valves are formed by three half-moon shaped (semi lunar) cusps. It should however be remembered that both the atrium contract at the same time followed by the simultaneous contraction of both ventricles.

Heart Disorders

When talking about heart conditions, doctors use the terms coronary heart disease (CHD) and the broader cardiovascular disease (CVD). CHD is used for any condition that affects heart function. CVD refers to both coronary heart disease and diseases of the circulation, such as stroke, when a clot blocks blood supply to the brain. Some common heart disorders are as given below:

1.      Angina also known as angina pectoris, occurs when an area of heart muscle does not get enough oxygen.

2.      Irregular heartbeats : Any abnormal rhythm of the heartbeat is known as an arrhythmia. Common causes of arrhythmia include electrical impulses coming from other areas of the heart instead of the sinus node that regulates heartbeat, electrical impulses coming from the sinus node but that take a different pathway through the heart and a very fast heart rate

3.      Cardiomyopathy: Cardiomyopathy means a disease of the heart muscle rather than the blood supply or the pacemaker. There is often no obvious cause for it, although coronary heart disease and high blood pressure, viral infections, excessive alcohol intake and thyroid disease can all be triggers.

4.      Heart failure : Although it sounds frightening, heart failure simply means the heart is less efficient at pumping blood around the body than it used to be. The most common cause is a heart attack, but anything that puts extra strain on the heart can result in a degree of heart failure, such as high blood pressure or a cardiomyopathy. Symptoms include severe breathlessness, fatigue and swelling of the ankles and feet.

5.      Congenital heart disease : Congenital heart disease is a heart abnormality that has been present from birth. Examples include failure to form the normal heart structure or holes between the chambers of the heart. In most cases the cause is unknown, but chromosomal disorders such as Down’s syndrome, rubella and viral infections can all increase the risk. Some congenital heart conditions are genetic, being inherited by a baby from his or her parents.

6.      Heart attack : A heart attack happens when a blood clot suddenly and completely blocks one of the heart arteries, starving part of the heart muscle of oxygen. This usually causes permanent damage to the heart muscle. The reason coronary arteries block off is due to them becoming narrowed over many years by a gradual build-up of fatty cholesterol-based material called atheroma within their walls. The usual symptom of a heart attack is pain in the centre of the chest that is a heavy, crushing type of pain often spreading to the arms, neck or jaw. There may be nausea and vomiting, sweating, shortness of breath and palpitations. Most heart attacks are the result of coronary heart disease.

7.      Heart valve problems : The heart is divided into four chambers, known as the right and left atrium and the right and left ventricles. Each of these chambers has valves that prevent blood flowing backwards into the chamber it has just come from. These valves usually ensure blood moves forward through the heart. Because of valve problem, the heart is put under extra strain, increasing the likelihood of heart failure.

8.      Infection: Both viral and bacterial infections can damage the valves of the heart and heart muscle. This can cause problems with the heart rhythm and increase the risk of heart failure.

References

1.      http://biology.about.com/od/anatomy/a/theheart.htm

2.      http://www.worldinvisible.com/apologet/humbody/heart.htm

3.      http://www.medicalnewstoday.com/articles/237191.php

4.      http://www.preservearticles.com/201105216892/essay-on-the-structure-and-functions-of-heart-for-students.html

5.      http://www.netdoctor.co.uk/hearthealth/heartdisease.htm#ixzz2M1gNgfYs

Ms Poonam Trikha