Electrical Conductivity of the Heart

Have you ever wondered just how important your heart is?Do you ever think about it to keep it beating?Well, the answer is probably no.Your heart is an amazing organ.It has the ability to function on its own.The heart is about the size of you fist lying in the middle of you chest.It is composed of numerous fibers and tissues, which allows it to operate and pump blood though out your body.The fibers allow electricity to be transmitted across the heart.The main areas that deal with the electrical impulses are the SA node, the AV node, the Bundle of His, and the purkinje fibers.Together, all these components contract the heart and pump blood through the body.
The sinoatrial (SA) node, or the natural pacemaker of the heart, is where the electrical impulses are generated.It is located in the upper wall of the right atrium near the opening from the superior vena cava.The SA node sets the contraction rate by generating nerve impulses which travel through the heart wall and then both atria contract.It does not need an external stimuli for the production of the electrical impulses, it does this on its own.The normal rate for the impulses to be generated is between sixty and eighty beats per minute.This rate can increase when one is aroused, exercising, angry, or frightened and this rate can decrease when one is sleeping or hibernating.From the SA node to the next receptor in the heart, it only takes fifty milliseconds for the signal to travel.
The next set of specialized tissue is the atrioventricular (AV) node.It is located in the bottom of the right atrium in the interatrial septum.When the electrical signals reach the AV node from the SA node, the signal is delayed for one-tenth of a second to allow the atria to empty their contents of blood.The AV node is slightly smaller in size than the SA node and the AV node causes both ventricles to contract.The normal rate of the AV node is between forty and…

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