resting membrane potential Flashcards
what is the first step in depolarization?
some v-gated Na+ channels open
what ion channels are open and which are closed during resting membrane potential
v-gated Na+ closed
v-gated K+ closed
Na+/K+ pump always working
After the first step of depolarization, when the ______ is reached and many more ______ open
threshold
v-gate Na+ channels
what positive feedback loop is part of the depolarization phase of a neuron?
v-gated Na+ channels open in response to a slight voltage change, more Na+ moves into the cell and causes even more v-gated Na+ channels to open
What causes voltage gated K+ channels to start to open?
all the Na+ channels are open, then they start to close and more K+ channels open
depolarization is a result of
Na+ movement into the cell
repolarization begins when v-gated Na+ channels close and more
v-gated K+ channels open
Repolarization occurs when
Na+ diffusion into the cell stops and K+ continues to diffuse out of the cell
what produces the after potential?
diffusion of K+ through v-gated channels
how does repolarization end?
v-gated Na+ channels are closed, K+ continues to diffuse out of the cell (afterpotential), and Na+/K+ pump works to reestablish the concentration required for the RMP
what does the Na+/K+ do?
reestablishes concentration to create RMP
What needs to happen for RMP to be reestablished?
Na+/K+ pump works
v-gated K+ channels close
the time when the sensitivity of an area to further stimulation decreases is called
refractory period
what are the two times of the refractory period and what are they?
absolute (complete insensitivity to another stimulus)
relative (a stronger than threshold stimulus could produce another AP)
