22 terms

action potential and graded potential

cell body and dendrites typically
Graded potential
axon hillock and axon
action potential
travels short distance-typically within cell body to axon hillock (.1-1.0)
graded potential
long distance- from axon hillock through entire length of axon (a few mm over a meter)
action potential
various size-declines with distance
graded potential
always the same size (all or none) does not decline with distance.
action potential
has an absent positive feedback
graded potential
has an present positive feedback
action potential
the stimulus for opening ion channels is -chemical or sensory stimulus(light, pressure,temperature)
graded potential
stimulus for opening ion channels is Voltage(depolarization, triggered by GP reaching the threshold)
action potential
Repolarization:voltage independent occurs when stimulus is no longer present
graded potential
Repolarization- Voltage regulate, occurs when Na+ channels inactivate and k+ channels open
action potential
Summation-stimulus responses can be summed to increase amplitude(size) of graded potential: temporal-increased frequency of stimuli, or Spatial-stimuli from multiple sources.
graded potential
Function-short distance signaling, depolarizationthat moves membrane potential towards the threshold for generation for AP
(postsynaptic potential)
Function-short distance signaling:hyperpolarization that moves the membrane potential away from the threshold for generation of Ap
(postsynaptic potential
Function-long distance signaling constitutes the nerve impulse
action potential
initail effect of stimulus- opens channels that allow stimultaneous Na+ and K+ fluxes
Excitatory(EPSP) Graded potential
Initial effect of stimulus- opens K+ or Cl-
Inhibitory (IPSP) Graded potential
Initial effect of stimulus-first opens Na+ channels, then k+ channels.
Action potential
peak membrane potential- becomes depolarized moves toward -0mV
Excitatory(EPSP)-Graded potential
Peak of membrane potential- Becomes hyperpolarized toward -90mV.
Inhibitory(IPSP)-Graded potential
peak membrane potential- +30mV to +50 mV
Action potential