Welcome to the Heart. If your browser supports audio media, you can click on any of the topics to the left of the heart and you be given a brief description of that part of the heart. If you have a slow modem connection, we suggest our readers to click on the portion of the heart you wish to read about and you will be sent to the appropriate bookmark, on the page below, for that topic.
| Overview of the Heart |
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| The Right Atrium and Ventricle | |
| The Left Atrium and Ventricle | |
| Electrical Pathways of the Heart | |
| V-Tach and V-Fib | |
| Back to defibrillation information |
| Overview of the Heart | The heart is a fist-sized organ that sits just left to the center of our sternum (breast bone). The heart is made of a muscle tissue called "Myocardium". This tissue is unique in that if it is damaged or dies, it will never regrow or heal itself. The heart consists of four chambers, two atrium on top and two ventricles on the bottom. The two atriums contract at the same time pushing blood into the ventricles, and then the two ventricles contract pushing blood into the lungs and body. ~TOP~ |
| The Right Atrium and Ventricle | The right atrium receives used blood, that is depleted of oxygen, through the upper and lower vena cava. The blood is then pumped through the Tricuspid Valve into the right Ventricle. The right Ventricle then pumps the blood through the Pulmonary artery into the lungs where the blood receives oxygen. ~TOP~ |
| The Left Atrium and Ventricle | The left Atrium receives blood from the lungs through the Pulmonary Vein. This blood has been given oxygen by the lungs. The left Atrium pumps blood through the Mitral (or Bicuspid) Valve into the left Ventricle. The left Ventricle then pumps blood through the Pulmonary Valve into the Aorta where the oxygenated blood is delivered to the body. ~TOP~ |
| Electrical Pathways of the Heart | The heart, like every other muscle in our body, is run by electricity produced from an ongoing chemical reaction at the cellular level. This process starts in the SA Node at the top of the right Atrium. The SA Node sends an electrical current along a path through the atriums that cause the muscle tissue to contract causing the first phase of the heart beat. Then the electrical pulse continues down to the AV Node at the bottom of the right Atrium. The AV Node sends the impulse down to the Bundle of His, in-between the ventricles, and then to the Bundle Branches that surround each ventricle. The Bundle Branches end in the Perkingie Fibers, this is where the electrical impulse leaves the pathway and stimulates the Ventricles to contract causing the second phase of the heart beat. ~TOP~ |
| V-Tach and V-Fib | Ventricular Tachycardia, or V-Tach, is when the ventricles are beating at such a rapid pace that they can not fill with blood and the victim looses circulation. Ventricular Fibrillation, or V-Fib, is when the electrical current in the ventricles is so sporadic that the muscle tissue just twitches as it is constantly bombarded with stray electrical impulses from other areas in the heart. V-Fib also causes the victim to loose circulation. Both types of arrythmias can be caused by many different types of chemical imbalances as well as injury from a trauma or a heart attack. ~TOP~ |
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