What neuron is NOT a apart of the efferent pathway? - ✔️✔️Sensory
The sympathetic and parasympathetic nervous system are divisions of what system? - ✔️✔️The
autonomic nervous system
Which glial cells from myelin in the central nervous system? - ✔️✔️Oligodendrocytes
What is a difference between the synaptic cleft and the synapse? - ✔️✔️The synaptic cleft is the space
between a presynaptic axon terminal and the postsynaptic dendrite, and a synapse includes all three of
these structures.
The neurons of the central nervous system are also known as - ✔️✔️interneurons
Where in the neuron is an action potential initially generated? - ✔️✔️Axon Hillock
The depolarization phase of an action potential results from the opening of which channels? -
✔️✔️voltage gated Na+ channels
The repolarization phase of an action potential results from? - ✔️✔️The opening of voltage gated K+
channels
Hyperpolarization results from? - ✔️✔️slow closing of voltage-gated K+ channels
What is the magnitude (amplitude) of an action potential? - ✔️✔️100mV
How is an action potential propagated along an axon? - ✔️✔️An influx of sodium ions from the current
action potential depolarizes the adjacent area.
,Why does the action potential only move away from the cell body? - ✔️✔️The areas that have had the
action potential are refractory to a new action potential.
The velocity of the action potential is fastest in which of the following axons? - ✔️✔️a small myelinated
axon
What opens first in response to a threshold stimulus? - ✔️✔️Voltage-gated Na+ channels
What characterizes depolarization, the first phase of the action potential? - ✔️✔️The membrane potential
changes from a negative value to a positive value.
Submit
What characterizes repolarization, the second phase of the action potential? - ✔️✔️Once the membrane
depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.
What event triggers the generation of an action potential? - ✔️✔️The membrane potential must
depolarize from the resting voltage of -70 mV to a threshold value of -55 mV.
What is the first change to occur in response to a threshold stimulus? - ✔️✔️Voltage-gated Na+ channels
change shape, and their activation gates open.
What type of conduction takes place in unmyelinated axons? - ✔️✔️Continuous conduction
An action potential is self-regenerating because __________. - ✔️✔️depolarizing currents established by
the influx of Na+ flow down the axon and trigger an action potential at the next segment
Why does regeneration of the action potential occur in one direction, rather than in two directions? -
✔️✔️The inactivation gates of voltage-gated Na+ channels close in the node, or segment, that has just
fired an action potential.
, What is the function of the myelin sheath? - ✔️✔️The myelin sheath increases the speed of action
potential conduction from the initial segment to the axon terminals.
What changes occur to voltage-gated Na+ and K+ channels at the peak of depolarization? -
✔️✔️Inactivation gates of voltage-gated Na+ channels close, while activation gates of voltage-gated K+
channels open.
In which type of axon will velocity of action potential conduction be the fastest? - ✔️✔️Myelinated axons
with the largest diameter
During an action potential, the rapid decrease in sodium ion permeability and the simultaneous and
rapid increase in potassium ion permeability is responsible for __________. - ✔️✔️the repolarization
phase
During an action potential, when does sodium ion permeability begin to significantly decline? - ✔️✔️at
the peak of depolarization
Which membrane potential opens a sufficient number of the voltage-gated Na+ channels to cause a
significant change in the membrane potential (making it much less negative) - ✔️✔️-60mV
A stronger stimulus to a neuron results in __________. - ✔️✔️stronger graded potentials
Whether a neuron fires an action potential depends on __________. - ✔️✔️a graded potential above
threshold voltage reaching the trigger zone
Which of the following would have the fastest action potentials? - ✔️✔️A myelinated axon with a large
diameter
What would happen to the membrane potential if a resting cell suddenly became more permeable to
Ca++? - ✔️✔️It would depolarize.
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