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The autonomic nervous system causes the SA node to fire

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Q: What causes the SA node to fire?
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If the SA node fails to fire what takes over?

If the SA node fails to fire the atrioventricular node should take over.


The SA node triggers an impulse that causes both atria to do what?

SA node sends an impulse for the atria to contract. AV node is then activated which contracts the ventricles.


Does the AV node initiates the contraction of the atria?

No, the sinoatrial (SA) node initiates contraction of the atria, which subsequently causes stimulation of the AV node, which then initiates contraction of the ventricles via the Purkinje fibers.


What is the medical term meaning natural pacemaker?

The sinoatrial node, abbreviated SA node, is the natural pacemaker. The SA node is a specialized collection of cells in the right atrium that can depolarize autonomously and do so on a regular basis. It is a bundle of neurons which 'fire' an electrical impulse at regular intervals, causing the heart muscle to contract. After the sinoatrial node has fired, the electrical impulse is sent to other nodes within the heart which then fire in a sequence that produces the heart beat.Sinoatrial node, SA Node


What causes heart beat?

cancer and exercise


What carries electrical impulses across the heart and causes the ventricles contract?

SA node.


Does the AV node control the heart rate?

Only if the SA Node isn't firing or there is some form of heart block. IIRC, under typical conditions, the SA node fires at 60-70 bpm. If that doesn't happen, or the electrical pathway between the two nodes is broken, the AV node will automatically fire at 50-60 bpm. If that doesn't happen, the ventricles themselves will fire at ~40 bpm. The logic of this system is that each of these nodes will fire on their own, so it is difficult to completely paralyze the heart. At 60 bpm the SA node sends one signal per second, at 50 bpm the AV node waits 1.2 seconds before automatically firing, and at 40 bpm the ventricles wait 1.5 seconds. Because the SA node is fastest, it is usually what paces the rest of the heart. In other words, the AV is a backup pacemaker (among other things).


The electrical impulse that causes the heart to contract is generated in the right atrium at the?

Sinoatrial, or SA node.


What is the main pace maker of the heart?

The primary pacemaker of a normal healthy heart is the sinus node (or SA node). It is located in the right atria of the heart.


What pacemaker of the heart initiates depolarization under normal conditions?

The primary pacemaker of the mammalian heart is the sino-atrial node. If the SA node fails, the atrioventricular node (AV node) takes over pacemaking.


Correct order of intrinsic cardiac conduction?

Its one of these, cant remember which one though: AV node, SA node AV bundle, Purkinje fibres. SA node, AV bundle, Purkinje fibres, AV node. SA node, AV node, AV bundle, Purkinje fibres. Purkinje fibres, SA node, AV node, AV bundle.


Where in the heart would the SA node be found?

The anterior, upper part of the right atrium.The Sinoatrial Node or SA Node is located in the right Atrium of the Heart. The SA node is responsible of the normal sinus rhythm.