A report on Electrical conduction system of the heart, Sinoatrial node and Atrioventricular node

Heart; conduction system. 1. SA node. 2. AV node. 3. Bundle of His. 8. Septum
Sinoatrial node shown at 1. The rest of the conduction system of the heart is shown in blue.
Image showing the conduction system of the heart. The AV node is labelled 2.
Overview of the system of electrical conduction which maintains the rhythmical contraction of the heart
Figure 2: Low magnification stained image of the SA node (center-right on image) and its surrounding tissue. The SA node surrounds the sinoatrial nodal artery, seen as the open lumen. Cardiac muscle cells of the right atrium can be seen to the left of the node, and fat tissue to the right.
Isolated heart conduction system showing atrioventricular node
Figure 3: Sinoatrial node action potential waveform, outlining major ion currents involved (downward deflection indicates ions moving into the cell, upwards deflection indicates ions flowing out of the cell).
Principle of ECG formation. Note that the red lines represent the depolarization wave, not bloodflow.
Schematic representation of the atrioventricular bundle
Different wave shapes generated by different parts of the heart's action potential

The electrical conduction system of the heart transmits signals generated usually by the sinoatrial node in the heart to cause contraction of the heart muscle.

- Electrical conduction system of the heart

The atrioventricular node or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of the heart; it is part of the electrical conduction system of the heart.

- Atrioventricular node

The pacemaking signal generated in the sinoatrial node travels through the right atrium to the atrioventricular node, along the Bundle of His and through bundle branches to cause contraction of the heart muscle.

- Electrical conduction system of the heart

These cells can produce an electrical impulse (action potential) that travels through the electrical conduction system of the heart, causing it to contract.

- Sinoatrial node

A wave of excitation spreads out from the sinoatrial node through the atria along specialized conduction channels.

- Atrioventricular node

Other cells within the heart (including the Purkinje fibers and atrioventricular node) can also initiate action potentials; however, they do so at a slower rate and therefore, if the SA node is functioning properly, its action potentials usually override those that would be produced by other tissues.

- Sinoatrial node
Heart; conduction system. 1. SA node. 2. AV node. 3. Bundle of His. 8. Septum

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The heart pumps blood with a rhythm determined by a group of pacemaker cells in the sinoatrial node.

These generate a current that causes the heart to contract, traveling through the atrioventricular node and along the conduction system of the heart.