action potential Flashcards
electrolytes
sodium (Na+)
potassium (K+)
polarization
electrical gradient (different electrical charge between inside and outside of neuron)
in resting potential, which is more negative?
inside is more negative than outside (i.e. -70 mV)
what does it mean when a neuron is in it’s resting potential?
it is stimulated and ready to fire
how are different charges maintained?
sodium-potassium pump: protein that allows 3 Na ions out and 2 K ions in
resting potential is…
disturbed by stimulation (by a neurotransmitter)
what is depolarization?
reduced polarization
threshold of excitation
-55 mV
stimulation that reaches the threshold leads to…
a massive depolarization of the neuron: action potential
what happens for depolarization?
sodium channels open and allow sodium inside
at the peak of the action potential, what happens?
sodium channels close; because the potassium channels are still open, polarization occurs and the membrane returns to its resting potential
what happens right after action potential?
the membrane is in a refractory period during which it resists the production of other action potentials
when does hyperpolarization occur?
the refractory period
what is hyperpolarization?
a time where the neuron cannot recharge as it goes below -70 mV
what is the all-or-none law?
signals are uniform in strength and speed
