Electrical conduction system of the heart: 1. SA node 2. AV node.
The heart has four chambers: two auricles and two ventricles, left and right. The right atrium receives venous blood from the body and sends it to the right ventricle which pumps into the lungs, where oxygen and is now the left atrium. From here the blood is due to left ventricle, which is distributed throughout the body and returns to the right atrium closing the cardiac cycle.
For the cyclic contraction of the heart is carried out synchronously and orderly, there is a system of power and stimulation comprising specialized cardiac muscle fibers in the transmission of electrical impulses. Although the heart innervation by the sympathetic nervous system, late even without this stimulus, the conduction system is autoexcitable. This is why an individual has no voluntary control over the beating of his heart.
Driving the system starts with the cardiac depolarization and must transmit electrical impulses from the auricles into the ventricles. This consists of the following elements: the sinus node, the atrioventricular node, the bundle of His, with its right and left branches and Purkinje fibers.
In the human body generates a wide variety of electrical signals, caused by the chemical activity that occurs in the nerves and muscles in the preparation. The heart, for example, leads to a characteristic pattern of voltage variations. The recording and analysis of bioelectrical events are important from the viewpoint of clinical practice and research. Potentials are generated at the cellular level, ie each cell is a tiny generator voltage.
Although it is possible with the use of microelectrodes to measure the potential of one of them, the clinical interest of bioelectrical signals are generated by coordinated activity of large cell groups. It is this type of synchronized activity, which involves many cells, which can be recorded using noninvasive methods, ie the use of metal electrodes placed on the surface of the body. An electrocardiogram (ECG) is a physical tests widely used to assess the condition of the heart in a non-invasive. This test is used to assess the state of the conduction system of the heart, muscle, and also, indirectly, the condition of this body as a pump and the appearance of rhythms Pathological tissue damage caused by driving signals electrical, or other non-cardiac disorders. The ECG is a graphical representation of the bioelectrical activity of the heart muscle, so a team record of ECG (electrocardiograph) is comparable to a voltmeter that performs a function Registrar.
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