The Human Heart Is One Of The Hardest.docx

The heart is undeniably one of the hard-working organ in a body. It is a continuously muscular working pump that circulates blood throughout the cardiovascular system of our body. The heart is located just underneath the ribcage, sternum and between the two lungs. The blood is the one that carries oxygen, nutrients and substances like hormones, wastes and other substances to the cells of the body. The heart pumps nearly five liters of blood in the human body to almost 1400 times per day in every day of our entire lives. The human heart is divided into four chambers which are the two upper chambers namely the atria and the other two lower chambers which are the ventricles. One of the atria, the right atrium chamber receives venous oxygen-depleted blood that has been circulating around through the body, not including the lungs and then pumps the blood into the right ventricle. The right ventricle pumps the blood that came from the right atrium to the pulmonary artery. The pulmonary artery will now send the deoxygenated blood into the lungs where it picks up oxygen, in exchange for carbon dioxide. Now, the left atrium chamber receives the oxygenated blood that came from the pulmonary veins of the lungs and pumps it into the left ventricle. Now, this left ventricle has the thickest muscle mass of all the chambers because the left ventricle is the hardest pumping part of the heart. It pumps the blood that flows into the heart and to the rest of the body other than the lungs.

The two atria of the heart are both located on the upper part of the heart. These two are responsible for receiving the blood that comes from the veins. The two ventricles of the heart are located in bottom part of the heart. These ventricles are responsible for pumping blood into your arteries. The atria and the ventricles contract to make the heart beat and to pump the blood through each chamber. The heart chambers are filled up with blood before each beat and the contraction enables the blood to flow out into the next chamber. These contractions of the heart are triggered by electrical impulses that are originating from a sinus node, also called the sinoatrial node (SA node) which is located in the tissue of the right atrium. These impulses then travel through the heart through the atrioventricular node or the AV node which is located near the center of the heart between the atria and the ventricles. These electrical impulses keep the blood in proper rhythm while flowing.

Another important part of the heart are the valves that are present in the heart. The heart has four valves at the end of each chamber which has one valve each chamber. Under normal conditions, these valves functions to prevent the backflow of the blood to the previous chamber. Enabling the heart to function properly as it continuously pumps blood. The heart’s valves are the Tricuspid (right AV) valve, Pulmonary valve, Mitral (left atrioventricular valve) valve and the Aortic valve. The Tricuspid Valve (right atrioventricular valve) opens to allow the blood to flow from the right atrium to the right ventricle while the Pulmonary valve opens to allow the blood to flow from the left ventricle into the pulmonary artery to the lungs. This enables the heart and rest of the body to receive more oxygen. Now the Mitral Valve (left AV) opens to let the blood flow from the left atrium to the left ventricle and the Aortic valve opens to let the blood flow out of the left ventricle to be able for the blood to flow to the heart and to the rest of body. These ventricles, maintain the pressure constant so that the pumping of blood of the heart becomes normal.

Now, the distributed blood throughout the body that goes to every cell and organs of the body will now have to go back to the heart to replenish oxygen, transport nutrients and other substances. Normally, the blood that are coming back from organs, except the lungs, enters the heart through the two major veins known as the superior and inferior vena cava. These blood are deoxygenated blood. The heart returns the venous blood back to the heart through the coronary sinus. And from these venous structures, the blood enters on the right atrium and it passes through the tricuspid valve into the right ventricle. The deoxygenated blood then flows through the pulmonary valve and into the pulmonary artery trunk. Then it travels through the right and left pulmonary arteries to the lungs where the deoxygenated blood receives oxygen during the exchange of gases. The blood that comes back from the lungs becomes oxygenated blood. It now travels through the right and left pulmonary veins into the left atrium of the heart. The blood now then flows through the mitral valve into the left ventricle, the heart’s largest and powerful chamber which pumps the oxygenated blood throughout the body through the aortic valve. After going through the aortic valve, the oxygenated blood flows into the aorta, extending upward from the heart. And from there, the blood moves through series of arteries to get to every cell in the body.

The very tiring task of the heart to keep the blood pumping in the body non-stop is a very complex process. This is why the heart needs to have a couple of maintenances to be performed. One of it is to regulate the timing of the beat that the heart makes. The heart’s system controls the timing of the pumping of the blood in the heart. The electrical system inside the heart keeps the heart beating at a regular beat and it adjusts the rate at which it beats. The heart maintains its normal heart rate and rhythm as long as the electrical system inside the heart is working properly to regulate the beat. Now if there is a problem or malfunction in the electrical system of the heart, it may cause an abnormal rhythm or uncoordinated beating inside the heart called arrhythmia. Either the heart is beating too fast called tachycardia or too slow called bradycardia.

By all means, we have to keep our heart muscle healthy because those four chambers of the heart are made of a special type of muscle called the myocardium. This muscle does the main pumping work of the heart. It relaxes to fill the chambers with blood and then contracts or squeezes out to pump the blood. The heart relaxes after pumping to be able to fill with blood because if the muscle is not able to relax enough, it will not pump blood efficiently. The functionality of the heart muscle has an effect on both to the heart’s contractility and ability to relax. These two determines whether the heart is able to pump enough blood normally each time it beats. Occurrence of problems with the contractility of the heart can be caused by problems with the muscles itself. Some viral infections of the heart muscle or an inherited heart muscle disorder are one of the causes of these problems that occur in the heart. Ischemia or the reduced blood flow to the heart muscle is also another disease that occurs in the heart. The heart muscle has a need of its own supply of blood because it needs oxygen and other nutrients to stay healthy just like all the other parts of the body. Fortunately, the heart has its own way of providing its muscles with blood that is rich with oxygen through the coronary arteries.

Hoit BD, Walsh RA (2011). Normal physiology of the cardiovascular system. In V Fuster et al., eds., Hurst's The Heart, 13th ed., vol. 1, pp. 94–117. New York: McGraw-Hill.

James, H. (2009). The ambassadors. Retrieved from http://books.google.com