Week 16: (C) Action Potential in cardiac contractile cell Flashcards

1
Q

What moves into cell?

A

Na+ infast

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2
Q

What channels open and close at the early depolarisation phase?

A
Na open
K closed (transient)
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3
Q

What move in and out during plateau phase?

A

K out fast

Ca in slowly

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4
Q

What channels open and close in the plateau phase?

A
open Ca L
close K (both transient and leaky)
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5
Q

What moves out of cell during late repolarisation phase?

A

k out fast

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6
Q

What channels open and close during late repolarisation?

A
open Ca L
increase K (v gated)
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7
Q

What channels are opened and closed in resting potential?

A
decrease K (v gated)
increase K (leaky)
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8
Q

When can a second action potential be triggered?

A

until the excitable cell membrane has recovered from the preceding AP
cannot initiate another AP during refractory period

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9
Q

How long does the refractory period last?

A

~250 ms

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10
Q

What is the factor responsible for the long refractory period?

A

is inactivation of the na channels responsible for the initial Na influx of the rising phase of the AP

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