Conductive system of the heart: structure, functions and anatomical and physiological features

An important characteristic of the work of the heart muscle is the automaticity of contractions. The harmonious work of the heart, which is based on successive contractions and relaxations of the muscular tissue of the atria and ventricles, is regulated by a cellular structure carrying a nerve impulse with a complex structure.

Conductive system of the heart is the most important mechanism for providing vital activity of the human body, consisting of a pulse generator (pacemaker) and individual complex formations intended for innervation of myocardial cycles. Consisting of a cell structure based on the work of P-cells and T-cells, it is designed to initiate a heartbeat and coordinate the reduction of the heart chambers. The first kind of cells has an important physiological function of the automatic - the ability to rhythmic reduction without a clearly expressed connection with the impact of any external stimuli.

T cells, in turn, have the ability to transmit contractile impulses generated by P-cells to the myocardium, which ensures its uninterrupted operation. Thus, the conduction system of the heart, whose physiology is based on a well-coordinated interaction of these two groups of cells, is a single biological mechanism, structurally entering the cardiac apparatus.

The conductive system of the human heart consists of several functional components: the sinoatrial and atrioventricular nodes, as well as the bundle with the left and right legs ending with Purkinje fibers. The sinoatrial (sinus) node located in the right atrium area is a small mass of muscle fibers of ellipsoidal shape. It is in this component, from which the conduction system of the heart begins, that nerve impulses emerge, causing contractile reactions of the heart. A normal automatic sinoatrial node is considered to be between fifty and eighty pulses per minute.

The atrioventricular component located below the endocardium in the posterior segment of the interatrial septum performs an important function for delaying, filtering and redistributing incoming impulses produced and sent by the sinoatrial node. The conduction system of the heart also performs the regulatory and distribution functions assigned to its structural component - the atrioventricular node.

The need for such functions is due to the fact that the wave of nerve impulses, instantaneously spreading through the atrial system and causing their response to the contractile response, can not penetrate immediately into the ventricles of the heart, since the atrial myocardium is separated from the ventricles by a fibrous tissue that does not transmit nerve impulses. And only in the region of the atrioventricular node such an insurmountable barrier is absent. This causes the wave of impulses, in search of an outlet, to rush to this important component, where they are uniformly distributed throughout the heart apparatus.

The conduction system of the heart also contains in its structure a bundle of His, connecting the atrial and ventricular myocardium, and Purkinje fibers, which form synapses on the cardiomyocyte cells and provide the necessary conjugation of muscle contraction and nervous excitation. In essence, these fibers are the final branching of the bundle of His, connected to the subendocardial plexuses of the ventricles of the heart.