SA Node vs. AV Node: What's the Difference?

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Key Difference

SA node and AV node are the major parts of the contractile system of the heart. Conducting system of a heart is the system of some component that forms an electrical conducting system, this system gets electrical impulses from Pace Maker and passes it on to the entire heart, the function of the conducting system is to transmit the impulse to maintain the contraction of the heart. SA node is the very first component of the conducting system of the heart. It is a small body of specialized muscular tissue in the wall of the right atrium of the heart. It produces the electrical impulse thus it is called PaceMaker of heart. The Pace Maker makes a firm pace of contraction of the heart and controls its activity of contraction. It transmits signal forward to AV node. AV node is the second component of conducting a system of the heart. It is a cluster of cells that controls the heart rate by receiving an electrical impulse from SA node. It is also one of the major components of the conducting system of the heart.  AV node is named atrioventricular node. It is situated in the center of the heart.

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Comparison Chart

SA NodeAV Node
AbbreviationSA node stands for sinoatrial node.AV node stands for the atrioventricular node.
Also Known AsSA node is known as the pacemaker of the heart.AV node is also known as pace setter of the heart.
Conducting System of HeartSA node is the first component of conducting a system of the heart.AV node is the second component of conducting a system of the heart.
Controlled BySA node is controlled by the autonomic nervous system (ANS). It is innervated by the parasympathetic nervous system by the Vagus nerve.AV node is controlled or influenced by the impulses from SA node.
LocationSA node is located in the superior lateral wall of the opening of superior vena cava (SVC).AV node is located in the posterior septal wall of right atrium just near to opening of the coronary sinus.
Beats per MinuteSA node has the rate of impulse discharge of almost 90-100 beats per minute.AV node normal firing rate is 40-50 times per minute.
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What is SA Node?

SA node stands for the sinoatrial node. It is the first component of conducting a system of the heart. It is a small body of specialized muscular tissue in the wall of the right atrium of the heart. It produces the electrical impulse thus it is called Pace Makers of heart. The function of a Pace Maker is to make a firm pace of contraction of the heart and control its activity of contraction. It transmits signal forward to AV node.SA node is located in the superior lateral wall of the opening of superior vena cava (SVC). It is a longer structure that is flattened. The interesting thing is that SA node transmits direct impulses to the two atria. SA node is controlled by the autonomic nervous system (ANS). It is innervated by the parasympathetic nervous system by the VAGUS nerve. The vagus nerve controls the vagal and sympathetic tone of heart. The rate of impulse discharge from the sinoatrial node is almost 90-100 beats per minute.

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What is AV Node?

AV node stands for the atrioventricular node. It is the second component of conducting a system of the heart. It is a cluster of cells that controls the heart rate by receiving an electrical impulse from SA node. It is also one of the major components of the conducting system of the heart. It is situated in the center of the heart. AV node is located in the posterior septal wall of right atrium just near to opening of the coronary sinus. It is a shorter structure that is half oval in its outline. AV node carries impulses to two ventricles though AV bundle and its various branches. AV node is controlled or influenced by the impulses from SA node. AV node is also known as pace setter of the heart. The normal firing rate of AV node is 40-50 times per minute. There are two pathways through the AV node; one is slow conduction pathway while other is fast conduction pathway.

SA Node vs. AV Node

  • SA node stands for the sinoatrial node, whereas AV node stands for the atrioventricular
  • SA node is known as the pacemaker of the heart, while AV node is also known as pace setter of the heart.
  • SA node is the first component of conducting a system of the heart. It is a small body of specialized muscular tissue in the wall of the right atrium of the heart, whereas AV node is the second component of conducting a system of the heart. It is a cluster of cells that controls the heart rate by receiving an electrical impulse from SA node.
  • SA node is controlled by the autonomic nervous system (ANS). Parasympathetic nervous system innervates it by the Vagus nerve, and contrary to this AV node is controlled or influenced by the impulses from SA node.
  • SA node is located in the superior lateral wall of the opening of superior vena cava (SVC), on the other hand, AV node is located in the posterior septal wall of right atrium just near to opening of the coronary
  • SA node has the rate of impulse discharge of almost 90-100 beats per minute, whereas AV node normal firing rate is 40-50 times per minute.

Explanatory Video

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