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Elements of Conduction System of Heart and Heartbeat

Hearts are characterized by an autorhythmic ability, in which they generate electricity and beat on their own without being governed by nervous.
Elements of the conduction system of the heart
Hearts are characterized by an autorhythmic ability, in which they generate electricity and beat on their own without being governed by nervous or hormonal input, i.e. they are not dependent on external mechanisms for every heartbeat. Although the intrinsic heart rate increases and decreases with sympathetic and parasympathetic nerve fibers respectively, it is provided both with autonomic nerve fibers. Furthermore, adrenaline (epinephrine) and thyroxine are circulating hormones that stimulate the heart. As well as originating impulses and conducting those impulses, the myocardium also performs synchronized and coordinated contractions, which is why the heartbeats.

Sinoarterial node (SA node)
The superior vena cava opens in the right atrium, which contains specialized cells. This regular impulse is produced because the sinoatrial cells are electrically unstable. Due to this instability, they depolarize (discharge) roughly 60 to 80 times a minute. The heart rate is set by the discharge that results directly from the depolarization and recovery (repolarization). Since the SA nodes discharge faster than anyone else in the heart, it performs the same function as the heart's pacemaker. SA node firing causes atrial contractions.

Atrioventricular node (AV node)
There is a small mass of neuromuscular tissue situated at the base of the atrioventricular valves within the atrial septum. It is normal for the atrioventricular nodes to transmit electrical signals only between the atria and the ventricles. Electrical signals take about 0.1 of a second to reach the ventricles; a delay exists here. Before the ventricles begin contracting, the atria perform their contractions. In addition to acting as a pacemaker, the AV node also becomes a pacemaker if the SA node experiences difficulty, as well as if the atria have difficulty transmitting impulses. The node sets a slower firing rate (40 to 60 bpm) than the SA node.

Atrioventricular bundle (AV bundle or Bundle of His)
Nodes comprised of AV fibers are referred to collectively as AV fiber constellations. After crossing the ring of fibrous tissue that separates the atria and ventricles, the AV bundle divides into right and left bundle branches at the top of the ventricular septum. Purkinje fibers are fine fibers that form within the ventricular myocardium. Several electrical impulses are transmitted into the myocardium through bundle branches and Purkinje fibers. These impulses cause contractions in this area, which then pump blood into the aorta and pulmonary arteries.

Nerve supply to the heart
This is the nervous system that regulates our heart rate, which comes from the medulla oblongata, which is the cardiovascular center. Among the parasympathetic nerves, the vagus nerve supplies primarily the SA, AV nodes, and atrial muscle. During parasympathetic stimulation, impulses are produced at a slower rate, causing the heartbeat to slow down and weaken. The sympathetic nerves are found in the SA and AV nodes as well as the myocardium of the atria and ventricles. The sympathetic nervous system stimulates the heart.

This sinus node (also known as the SA node or sinoatrial node) generates an electrical stimulus. These are small, specialized tissues in the chambers of the right side of the heart (atria). It generates an electrical stimulus regularly, between 60 and 100 times per minute under normal circumstances. It generates an electrical stimulus regularly, between 60 and 100 times per minute under normal circumstances. It then activates the atria. By sending the electrical stimulus down the conduction path, the electrical stimulus causes the ventricles of the heart to contract and pump blood. The lower chambers of the heart become active very soon after the two upper chambers of the heart have been stimulated (atria).

Atrioventricular nodes convert electrical impulses into contracts within the heart. A bundle of His transports impulses from here into the ventricles after being slowed down for a short time. Bundle branches stimulate the right and left ventricles by dividing the bundle of His into right- and left-sided pathways. Normally, the heart contracts 60 to 100 times every minute as electrical impulses pass through it as they move through the heart. The contractions of the ventricles represent heartbeats. Atrial contraction occurs just a fraction of a second before ventricle contraction so that atria fill with blood before ventricles do.
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Ankur Choudhary is India's first professional pharmaceutical blogger, author and founder of pharmaguideline.com, a widely-read pharmaceutical blog since 2008. Sign-up for the free email updates for your daily dose of pharmaceutical tips.
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