Introduction
The pumping mechanism of the heart is essential for survival. The heart pumps blood that is rich in oxygen and nutrients to the organs and tissues of the body. The heart beats around 100,000 times a day and pumps about 2,000 gallons of blood daily. The heart beats to pump blood through a system of blood vessels that constitute the circulatory system. This article gives an insight into the pumping mechanism of the heart.
What Are the Structures of the Heart?
The heart is situated under the rib cage, between the lungs. The heart is made of strong muscles that contract and expand during the pumping mechanism. The coronary arteries are the blood vessels that are present on the surface of the heart. These arteries supply the heart muscle with oxygen-rich blood. The superior vena cava, the inferior vena cava, and the pulmonary veins are the major blood vessels that enter the heart. The pulmonary artery is another blood vessel that leaves the heart with oxygen-poor blood to enter the lungs. The aorta leaves the heart and supplies the body with oxygen-rich blood.
The heart is a hollow organ that is divided into the right and left sides by the septum (a muscular wall). It is further divided into four chambers on the right and left sides. The two upper chambers on the right and left sides called the atrium, receive blood from the veins, and the two lower chambers, called the ventricles, pump blood into the arteries. The heart has four valves that act as gates to control the movement of the blood. It includes the aortic, mitral, pulmonary, and tricuspid valves.
What Does the Heart Do?
The atria and ventricles function together to pump blood to the organs and tissues of the body.
The left side of the heart pumps oxygen-rich blood into the arteries to supply the tissues and the organs. Blood delivers nutrients and oxygen throughout the body, becomes oxygen deficient, and comes back to the heart through the veins and enters the right side of the heart. This oxygen-poor blood is sent to the lungs to receive oxygen and eliminate carbon dioxide. The right side of the heart receives blood that has delivered oxygen and nutrients to the body and sends this blood to the lungs for oxygenation. The left side of the heart receives oxygen-rich blood, and it is pumped into the arteries to supply nutrients and oxygen throughout the body.
How Does the Heart Pump?
The pumping mechanism of the heart comprises two phases: systole and diastole. In systole, the heart contracts and pushes blood out of the chambers. Diastole indicates the period between contractions when the muscles of the heart relax and the chambers are filled with blood. The right and left side of the heart pumps together. The blood is pumped in a pattern, and it is repeated over and over throughout life for a continuous flow of blood to the heart, lungs, and body. The mechanism of heart pumping is as follows:
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The superior vena cava collects oxygen-deficient blood from the structures above the diaphragm, such as the head, neck, arms, and chest, and the inferior vena cava collects oxygen-poor blood from the structures below the diaphragm, such as the legs, feet, and organs in the pelvis and abdomen. These veins empty the oxygen-poor blood from the body into the right atrium of the heart.
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The right atrium contracts and pumps blood into the right ventricle through the tricuspid valve that opens during this function, and it shuts after the ventricle is filled to prevent the backflow of blood.
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The ventricle then contracts and pumps blood into the pulmonary artery through the pulmonic valve to reach the lungs. The oxygen-poor blood enters the lungs to receive oxygen and gets rid of carbon dioxide, and returns to the left atrium of the heart through the pulmonary veins to empty the oxygen-rich blood.
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The left atrium contracts and pumps blood into the left ventricle through the mitral valve. The mitral valve shuts after the ventricle is filled to prevent the backflow of blood.
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The left ventricle contracts to pump blood into the aorta through the aortic valve to supply the organs and tissues of the body.
What Causes the Heart to Pump?
The electrical system of the heart is responsible for the pumping mechanisms of the heart. The heartbeat is stimulated by the electrical impulses that travel down the heart. The impulse initiates in a small bundle of specialized cells called the sinoatrial node (SA node), situated in the right atrium. This node is also referred to as a pacemaker. This electrical impulse spreads through the walls of the atrium and initiates contraction.
The atrioventricular node (AV node), a cluster of cells situated in the center of the heart, slows the electrical signals before the signals enter the ventricles. This delay allows the atria to contract before the ventricular contraction. The Bundle of His-Purkinje fibers sends the impulses to the walls of the ventricles to cause ventricular contraction. These electrical signals cause the heart to beat or pump.
What Are the Diseases Associated With the Abnormalities in the Heart and Its Mechanisms?
Abnormalities in the heart and circulatory system can result in heart and circulatory diseases. Abnormalities in the structure cause congenital heart disease. Problems in the heart and circulatory system can cause heart attack, angina, and stroke. Abnormalities in electrical signals can cause arrhythmias. Disorders in the heart valves can result in stenosis or regurgitation.
Conclusion
The heart pumps to deliver oxygen and nutrient to the organs and tissues of the body. This mechanism of pumping is essential for survival. The heart beats continuously around 100,000 times a day and pumps about 2,000 gallons of blood daily. It is crucial for the functioning of the whole body and the organ systems. Various structural and functional abnormalities in the heart can disrupt the normal mechanism of pumping, resulting in heart and circulatory system diseases. Hence, cardiac health and normal functioning of the heart is essential for the well-being of an individual.
