Neuronal Signaling and Neurons Flashcards
what ion plays the most important role in generating the RMP?
K+
what is RMP?
potential to do work due to separated electrical charge on opposite sides of membrane
T/F: the cell membrane is leaky to K+?
True
what is equilibrium potential?
reflects an equilibrium between electrostatic attraction/repulsion and concentration differences
Stages of an AP
RMP,
Depolarization,
Re-polarization,
Hyper-polarization
what causes hyper-polarization?
K+ channels are slow to close, allows more K+ efflux to occur
Na+ channels exert what type of feedback on membrane potential?
positive feedback
K+ channels exert what type of feedback on membrane potential?
negative feedback
what is a refractory period?
period in which a 2nd stimulus arriving at the synapse will not initiate a 2nd AP
what is the relationship been neuron size and AP velocity?
larger fiber = faster AP
T/F: threshold potentials are achieved by a single graded potential
FALSE
the collective equilibrium potential creates what?
resting membrane potential
what is an action potential?
events that change the potential on the cells to bring about a response
what causes depolarization?
influx of + charges
when does depolarization stop?
when Na equilibrium potential is reached causing Na channels to close
why doesn’t repolarization just stop at RMP? why do we have hyperpolarization?
K+ channels don’t all close at the same time, K+ continues to leak outside of the cell
what type of feedback loop would an action potential be?
positive feedback
what type of feedback loop is depolarization?
negative feedback
why is repolarization negative feedback?
the channels close as a result of too much K leaking out
T/F: APs decrease in magnitude with transmission
False, they remain all or none
ratio of fiber diameter to speed of AP
larger fiber = faster AP
why are larger fibers faster?
less internal resistance to current, membrane threshold is attained more quickly
how does the presence of Schwann cells affect transmission of APs?
faster velocity
what is the difference between an AP and a graded potential?
AP are all or nothing, GP can have a graded response based on the stimulus and have no refractory period
