Neurophysiology 22% Flashcards
(36 cards)
influx sodium, ascending phase, impulse likely, Na gates close
depolarization
efflux potassium, inside membrane less positive, membrane potential towards resting, descending phase
repolarization
threshold occurs
-55 and -50 mV
before AP begins, polarized (largely - MP)
resting stage
change in permeability of membrane
action potential
excitatory NTs
NE, glutamate, NO
inhibitory NTs
ACh, dopamine, glycine, GABA, serotonin
inactivation gate will not reopen until
membrane potential is at “resting” level
neuron sending the signal
presnyaptic neuron
neuron receiving the signal
postsynaptic neuron
most synapses, from axon to dendrite
axodendritic
from axon to soma
axosomatic
from axon to axon
axoaxonic
tunnels (connexons) to connect cytosol of two cells
gap junctions
synaptic delay
0.5 m/sec
occurs 10,000ths of a second, Na+ channels begin to close and K+ channels open wider; rapid diffusion of K+ to exterior (re-establishes normal negative RMP)
repolarization stage
permeable to Na ions as makes inside neuron “more towards positive” -90mV immediately neutralized
depolarization stage
influx of sodium
depolarization
efflux of potassium
repolarization
no AP possible
absolute refractory
AP available with increase potential
relative refractory
many synapses single cell
spatial summation
rapid succession of AP, few synapses
temporal
strychnine poisoning binds to and blocks ___ cuases massive tetanic contractions, diagphragm cant relax, cant breathe, DIE
glycine receptors
