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What happens in a heart when an action potential is generated in the SA node?
Wiki User
∙ 13y ago
It simulates the node, which then sends impulses to the AV node, which disperses these impulses through the cardiac muscle to cause a cardiac cycle (rhythmic beating and relaxing of atria and ventricles)
Wiki User
∙ 12y ago
Wiki User
∙ 13y agoMyocardial contraction
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What happens to the heart when an action potential is generated in the SA node?
it contracts
What happens in the heart when an action potential is generated in the SA node?
Myocardial contraction
Why do you keep the heart from entering tetanus?
The action potential of cardiac muscle is prolonged consisting of the depolarization spike and plateau and a repolarization period. The action potential causes a long refractory period of about 250-400 milliseconds in the heart.
Does atrial systole occur before or after the firing of the sinoatrial node?
The SA node makes the action potential for the heart. Atrial systole must occur after the action potential.
What are autorhythmic fibers?
They are fibres which generate AP(action potential) which trigger heart contractions.
Why is the cardiac action potential longer?
The reason why cardiac muscle has a longer action potential is to extend the absolute refractory period to prevent another action potential. If too many action potentials stimulate the cardiac muscle it can get into tetanus which keeps the heart continuously contracted without relaxation.
How can electrolyte imbalance control your heart function?
Electrolytes such as Sodium and potassium help the heart contract through a process called action potential. When the heart is at -60 MV the cell will open up allowing sodium into the cardiac cells causing a contraction. Look up action potential.
What are pacemaker potentials and the action potential they trigger?
Pacemaker potentials are automatic potentials generated and are exclusively seen in the heart. They arise from the natural "leakiness" of the membrane that pacemaker cells have, resulting in passive movement of both Na+ and Ca2+ across the membrane, rising the membrane potential to about -40mV. This results in a spontaneous depolarization of the muscle that has a rise in the curve that is nowhere near as steep as the action potential of other cells. Upon depolarization, the cell will return back to its resting membrane voltage, and continue the potential again.
What is blood flow generated by?
The flow of blood times the resistance of the blood vessels.
What is the cause of compensatory pause after an extrasystole?
Extrasystole is due to the irregular contraction of the ventricle before the atria. When this happens, an action potential is elicited and the ventricle contracts. The action potential had a refractory period, during which the intrinsic heart rate attempts to fire but cannot elicit a contraction. This is why extrasystole is often referred to as skipping a beat. The compensatory pause is the time it takes for the beat to resume normal contraction.
What is a sinus rhythm?
When the heart is functioning properly the sinus node controls the firing of action potential that contract the heart. When the sinus node dominates the heart will contract in a synchronized and effective rhythm This is called sinus rhythm.
Why is the action potential of the cardiac muscle cells long?
This is because the heart needs enough time to pump blood out to the main arteries. The action potential of the heart (ventricles) is elongated by the opening of the voltage gated Calcium channels causing an influx of positively charged Calcium ions to the inside of the muscle cells and therefor maintaining the depolarized (excited) state of the cell membrane for a longer period of time. This is phase 2 of the action potential which is also called the Plateu Phase.
