Anatomy And Physiology

How the Heart Works



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Associated with life and love, the heart is one of the most intricate and fascinating organs of the human body. This article is intended to provide a basic understanding of the anatomy of the heart and how it functions.

The heart is the most important muscle in the human body. Without a heart a person cannot survive. The human heart is roughly the size of your fist and is located roughly in the center of your chest cavity (also called the thoracic cavity). The heart is the central pump of the circulatory system, pumping the blood and circulating it throughout the body. The heart has four chambers. The two upper chambers are called the atria, and the two lower chambers are called the ventricles. A muscle wall called the septum divides the two sides of the heart. Both atria contract at the same time, forcing blood into the ventricles. The ventricles then contract simultaneously and pump the blood out of the heart and throughout the body.

Within the heart there is special tissue that produces and sends electrical impulses to the heart muscle that trigger the heart to contract. These electrical impulses originate in the sinoatrial node which is located within the wall of the right atrium. Simply put, this is a natural built-in pacemaker. Every time the heart beats, an electric-like signal is sent out. These signals can be measured with a special machine called an electrocardiogram (EKG or ECG), which allows a physician to adequately diagnose a patients current condition of their heart.

In general, the role of the heart is to pump the blood out of the heart, into the lungs and throughout the body to deliver essential nutrients and oxygen. The flow of blood in the heart has a defined path that it travels. The blood flows into the right atrium through the vena cavae (two large veins that return blood from the body to the heart), where it then flows into the right ventricle. When the right ventricle contracts, the deoxygenated blood is pumped out of the heart and into the lungs via the pulmonary arteries. Once in the lungs carbon dioxide is released out of the blood to be expelled from the body during respiration, and fresh oxygen fills the blood. From the lungs the blood then returns to the left atrium via the pulmonary veins and into the left ventricle, where the blood is pumped into the aorta and out to the body.

There are two distinct systems that are at play within the heart; the pulmonary circulatory system that circulates blood from the heart to the lungs only and the systemic circulatory system that transports the oxygen rich blood from the heart and throughout the body.

The heart is not only a very efficient pump, but it is the hardest working muscle in the body, beating on average approximately 115,000 per day. In a normal healthy heart, the heart will beat on average sixty to eighty times a minute. The heart is designed to naturally slow down when the body is at rest and speed up when the body is under stress, such as in physical exercise. The contractions of the heart are involuntary, which means that a person doesn't need to think about telling the heart to contract.

The heart, like all other organs of the body is susceptible to many diseases if it is not taken care of. The most common disease is Coronary Artery Disease (CAD). There are many things that you can do to aid in the prevention of obtaining future heart problems. Start by having regular check-ups with your physician to monitor your blood pressure and cholesterol levels. Eat a healthy diet. Include some amount of daily exercise into your routine. Quitting smoking can also have great beneficial effects on your heart.

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