Almost every adult person, when there are problems with health, is trying to “make a diagnosis”. If you have a fever, a headache, the first thing you do is measure the temperature. If you suddenly feel unpleasant sensations in the chest, interruptions in the work of the heart, you involuntarily begin to listen to how your heart beats and, most simply, you try to count the pulse.
The heart has a number of functions that determine the features of its work. One of them is the function of automatism, which consists in the ability of the heart to generate electrical impulses on its own. The function of automatism is possessed by cells of the sinus node and fibers of the conduction system of the heart.
The sinus node (CS) located in the right atrial wall is a small area of ??accumulation of special cells capable of generating electrical impulses or heart rhythm on their own. It is the sinus node that regulates the frequency and strength of the heartbeats, generating electric excitation pulses at a certain frequency. Sinus node is a natural driver of heart rhythm, therefore the normal heart rhythm is called sinus rhythm.
From the sinus node impulses enter the atrioventricular node (AV node), which is located at the border of the atria and ventricles. The cells of the AV node have a slower rate of conduction, so the signal is “delayed”, and then through the bundle of the Guiss and its right and left legs it passes to the right and left ventricles of the heart, causing their contraction. Thus, sinus pulses, spreading all over the heart, ensure its rhythmic and consistent reduction. If the sinus node ceases to produce the required number of pulses, the atrioventricular node replaces it. Thus arises the atrioventricular rhythm of the heart. The AV node also has a protective function that manifests itself if in the atria spontaneously generated an excessive number of pulses. Filtering unnecessary electrical impulses,
The central nervous system constantly monitors the needs of the body and, if necessary, accelerates or slows the work of the heart. With physical activity, the body needs more oxygen and nutrients, so the sinus node begins to generate excitation pulses at a higher frequency and the heart beats more often. So, during intense physical activity, the pulse can reach 130-150 beats per minute.
Heart rhythm, or heartbeat, you can feel, putting a hand on the heart or measuring the pulse.