Week 16: (C) Action Potential in cardiac contractile cell Flashcards
What moves into cell?
Na+ infast
What channels open and close at the early depolarisation phase?
Na open K closed (transient)
What move in and out during plateau phase?
K out fast
Ca in slowly
What channels open and close in the plateau phase?
open Ca L close K (both transient and leaky)
What moves out of cell during late repolarisation phase?
k out fast
What channels open and close during late repolarisation?
open Ca L increase K (v gated)
What channels are opened and closed in resting potential?
decrease K (v gated) increase K (leaky)
When can a second action potential be triggered?
until the excitable cell membrane has recovered from the preceding AP
cannot initiate another AP during refractory period
How long does the refractory period last?
~250 ms
What is the factor responsible for the long refractory period?
is inactivation of the na channels responsible for the initial Na influx of the rising phase of the AP