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15 Cards in this Set

  • Front
  • Back
When excitable cells are at rest they have lots of __ on the inside and lots of ___ outside of the cell.
K+ on the inside, Na+ on outside
An action potential occurs when a _______ is initiated and propagates itself down the length of a neuron or muscle cell.
depolarization
4 types of action potentials
1) all-or-none
2) Self-propagatory: once
created, they self
initiate down the line to
end
3) irreversible: once start,
can't stop
4) non-decremental: voltage
isn't lost
-AP has same value at end
Membranes normally exist at the __________.
resting membrane potential
What type of channels do non-excitable cells lack?
voltage gated channels
Sub-threshold stimulus is the ________ potential that leads up to the threshold.
generator
______ occurs when threshold of local voltage gated channels causes them to open.
depolarization
When maximum depolarization is reached voltage gated Na+ channels start to close, then K+ channel start to open and the membrane potential moves back in the ______ direction.
negative
In the ______ period repolarization is occurring, the Na+ channels are closed and they cannot be reopened.
Absolute Refractory
In what period is unusually strong stimuli needed to depolarize the membrane?
relative refractory
Which action potential, slowly or very quickly, consists of regular conduction of AP along unmyelinated neurons?
slowly
Which action potential, slowly or very quickly, consists of saltatory (jumping) conduction of AP between nodes of ranvier (exposed membrane) on myelinated neurons; also needs to be supplied with ATP, not cheap?
very quickly
In AP propagation along an unmyelinated neuron, _____ normally carry the AP away from cell body to the next cell.
axons
In an unmyelinated neuron, if the stimulus occurs aftificially in the middle of an axon, (injury) the _____ can travel both ways.
AP
2 non-excitable cells the myelin sheath is created by
1) oligodendrites
2) schwann cells