Nurturing Life Sciences
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The original template sequence will also be copied during the second and all subsequent cycles to generate the 'long product'. Therefore, the long product continues to increase linearly, while the 'correct PCR' product will multiply exponentially.
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#Unit 7. System Physiology – Animal
SA node has an unstable resting membrane potential.
The “resting membrane potential” of the sinus nodal fiber between discharges has a negativity of about −55 to −60 millivolts.
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The cause of less negative RMP of SA node is that the cell membranes of the sinus fibers are naturally leaky to sodium and calcium ions.
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The inherent leakiness of the sinus nodal fibers to sodium and calcium ions causes their self-excitation.
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SA node has Prepotential or pacemaker potential which is the gradual potential rise from the resting membrane potential to threshold ( -40 mV) & this occur spontaneously.
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Membrane ion channels that play important roles in generation of the action potential:
T (transient) channels
L (long-lasting) channels
Voltage gated potassium ion channel
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Between heartbeats, influx of positively charged sodium ions causes a slow rise in the resting membrane potential in the positive direction.