YOUR HEART - THE ENGINE OF LIFE

The heart weighs between 7 and 15 ounces (200 to 425 grams) and is a little larger that the size of your fist. by the end of a long life, a person's may have beat (expanded and contracted) more than 3.5 billion times. In fact each day the average heart beats 100,000 times, pumping about 2,000 gallons (7,571 liters) of blood.

The heart is located between our lungs in the middle of your chest, behind and slightly to the left of your breastbone (sternum). A double layered membrane called the pericardium surrounds your heart like a sac. the outer layer of the pericardium surrounds the roots of your heart's major blood vessels and is attached by ligaments to your spinal column, diaphragm, and other parts of your body. The inner layer of the pericardium is attached to the heart muscle. A coating of fluid separates the two layers of membrane, letting the heart move as it beats, yet still be attached to your body.

Heart has 4 chambers. The upper chambers are called the left and right atria, and the lower chambers are called the left and the right ventricles. The left ventricle is the largest and strongest chamber in your heart. The left ventricles chamber walls are only about a half-inch thick, but they have enough force to push blood through the aortic valve and into your body.

MYCARDIUM - HEART MUSCLE                                         

The muscle responsible for pumping the blood is called the myocardium (myo means 'muscle', cardia means 'heart'). The heart has three layers of tissue, the myocardium, the epicardium and the endocardium. The myocardium is the thick main layer of heart muscle made up predominantly of cells called myocytes. It's outside surface is covered by a thin glossy membrane, the epicardium. Another smooth glossy membrane, the endocardium covers the inside surfaces of your Heart's four chambers, the valves and the muscles that attach to those valves.

The second part of the pumping phase begins when the ventricles are full of blood. The electrical signals from the SA node travel along a pathway of cells to the ventricles, causing them to contract. This is called systole. As the tricuspid and mitral valves shut tight to prevent a back flow of blood, the pulmonary and aortic valves are pushed open. While blood is pushed from the right ventricle into the lungs to pick up oxygen, oxygen-rich blood flows from the left ventricle to the heart and other parts of the body.

After blood moves into the pulmonary artery and the aorta, the ventricles relax, and the pulmonary and aortic valves close. The lower pressure in the ventricles causes the tricuspid and mitral valves to open, and the cycle begins again. This series of contractions is repeated over and over again, increasing during times of exertion and decreasing while you are at rest.

Your heart does not work alone though. Your brain tracks the conditions around you, climate , stress, and your level of physical activity and adjusts your cardiovascular system to meet those needs.

The human heart is a muscle designed to remain strong and reliable for a hundred years or longer. By reducing your risk factors for cardiovascular disease, you may help your heart stay healthy longer.

Hope you liked this blog!                                                                                                    

This article is written by Dr. Bimal Chhajer (SAAOL Heart Centre Chhatarpur)