Bio 2050 - Anatomy and Physiology » Spring 2021 » Neurophysiology

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Question #1
As a neuron's refractory period ends, its sodium channels are changing from
A.   their activated state to their resting state.
B.   their inactivated state to their resting state.
C.   their resting state to their inactivated state.
D.   their resting state to their activated state.
Question #2
One of the ways in which neurotransmitter is removed from the synaptic cleft is
A.   dendritic lassos.
B.   phagocytosis by a macrophage.
C.   endocytosis by the postsynaptic cell.
D.   reuptake by the presynaptic cell.
Question #3
According to Ohm's law, current is
A.   inversely related to both voltage and resistance.
B.   indirectly related to voltage and directly related to resistance.
C.   directly related to voltage and inversely related to resistance.
D.   directly related to both voltage and resistance.
Question #4
Action potentials are generated by the opening of ________ gated channels and they occur on the ________.
A.   chemically, axon
B.   voltage-, axon
C.   voltage-, dendrite
D.   chemically, dendrite
Question #5
Hyperpolarization of a neuron results from
A.   the entry of any ion.
B.   either the entry of an anion or the exit of a cation.
C.   the entrance of either sodium or potassium.
D.   either the entry of a cation or the exit of an anion.
Question #6
The main way acetylcholine is cleared from a synapse is by
A.   degradation by an enzyme.
B.   uptake by the postsynaptic cell.
C.   reuptake by the presynaptic cell.
D.   being engulfed by a supporting glial cell.
Question #7
Maintenance of appropriate ion concentrations (especially after nerve impulses that involved ion diffusion) is primarily the job of
A.   chemically gated channels.
B.   voltage-gated channels.
C.   sodium-potassium pumps.
D.   mechanically gated channels.
Question #8
To measure the resting potential of a neuron, a physiologist would place
A.   one microelectrode inside the neuron and another in the interstitial fluid.
B.   one electrode inside the cell and another outside the body.
C.   two electrodes inside the neuron.
D.   one electrode inside the cell and another inside another cell.
Question #9
Which occurs first?
A.   Absolute refractory period
B.   Relative refractory period
Question #10
A graded potential is one that
A.   varies in size depending on the magnitude of the stimulus (larger voltage change for stronger stimulus).
B.   lasts for several seconds after ion channels have opened, closed, and reset.
C.   is all or none (always the same intensity).
D.   travels the length of the nerve fiber (is long-distance).
Question #11
When a neuromodulator slows the reuptake of a neurotransmitter or causes expression of an increased number of receptors on postsynaptic neurons, the effect is called
A.   facilitation.
B.   presynaptic potentiation.
C.   temporal summation.
D.   spatial summation.
E.   recruitment.
Question #12
In a myelinated axon, the greatest concentration of voltage-gated ion channels is in the
A.   myelinated regions.
B.   neurofibril nodes.
Question #13
The slowest category of nerve fibers are the
A.   D fibers, and they conduct impulses at 0.1 meter per second.
B.   C fibers, and they conduct impulses at 1 meter per second.
C.   C fibers, and they conduct impulses at 100 meters per second.
D.   A fibers, and they conduct impulses at 10 meters per second.
E.   D fibers, and they conduct impulses at 0.01 meter per second.
Question #14
When multiple presynaptic neurons release neurotransmitter at various locations onto the postsynaptic neuron at the same time, this results in
A.   several action potentials.
B.   temporal summation.
C.   spatial summation.
D.   suprathreshold hyperpolarization.
Question #15
A postsynaptic potential is a graded potential.
A.   FALSE
B.   TRUE
Question #16
A neuron's membrane contains more potassium leak channels than sodium leak channels.
A.   FALSE
B.   TRUE
Question #17
When a neurotransmitter opens a chemically gated ion channel that allows sodium to enter the postsynaptic cell, the result is an
A.   IPSP.
B.   EPSP.
Question #18
Arrival of an action potential at the synaptic knob results in
A.   opening of chemically gated calcium channels and diffusion of calcium out of the synaptic knob to the interstitial fluid.
B.   closure of voltage-gated calcium channels in the synaptic knob membrane.
C.   opening of voltage-gated calcium channels and diffusion of calcium into the synaptic knob.
D.   opening of chemically gated calcium channels and diffusion of calcium into the synaptic knob.
E.   opening of voltage-gated calcium channels and diffusion of calcium out of the synaptic knob to the interstitial fluid.
Question #19
A graph of an EPSP would plot time against a voltage trace that would resemble
A.   a valley where the low point is the farthest away from the threshold value.
B.   a hill where the high point is the farthest away from the threshold value.
C.   a valley where the low point approaches the threshold value.
D.   a hill where the high point approaches the threshold value.
Question #20
When voltage-gated K + channels open on the conductive segment of a neuron,
A.   potassium exits, repolarizing the cell to a negative value.
B.   potassium exits, depolarizing the cell to an even more negative value.
C.   potassium enters, depolarizing the cell to a positive value.
D.   potassium enters, repolarizing the cell to a positive value.
E.   potassium enters, repolarizing the cell to a negative value.

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