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Exam 1 Review
Terms in this set (39)
Which glial cells function as metabolic intermediaries between capillaries and neurons?
a. Schwann cells
d. Microglial cells
Neurons that relay sensory signals to integrative centers of the CNS are called
b. afferent neurons.
c. synaptic neurons.
d. efferent neurons.
What allows the action potential to return to a repolarized state?
a. Voltage-gated Na+ channels become inactivated.
b. Voltage-gated K+ channels become inactivated.
c. Na+ reaches equilibrium across the neural membrane and stops leaking in.
d. Voltage-gated Na+ channels close.
The neuron converts an electrical signal to a chemical signal in the
b. presynaptic terminal.
c. cell body.
d. axon hillock.
If ouabain was used to block Na+-K+-ATPase pumps,
a. Na+ would go to equilibrium across the cell membrane.
b. the membrane potential would become more negative.
c. the concentration of K+ would be equal on both sides of the membrane.
d. the cell would maintain steady state with a different membrane potential.
If a current pulse is generated on the membrane and creates a passive potential, which statement will be true?
a. The change in the membrane potential will increase as the distance from the current pulse increases.
b. The change in the membrane potential will decrease as the distance from the current pulse increases.
c. The change in the membrane potential will remain constant throughout the length of the membrane.
d. The change in the membrane potential will fluctuate depending on the strength of the initial current pulse.
_______ are responsible for extending the time of the cardiac action potential relative to a neural action potential.
a. Slow Ca2+ channels
b. Slow Na+ channels
c. Slow K+ channels
d. Voltage-gated Na+ channels
Which of the following
contributes to the cell's membrane potential?
a. Permeability to K+
b. Permeability to Na+
c. The overall resistance of the membrane
d. Electrogenic ion pumps
In myelinated axons, action potentials occur
a. all along the axon.
b. only at the internodes.
c. only at the initial segment of the axon.
d. only at the nodes of Ranvier.
Which statement regarding the action potential is
a. In an extremely long axon, the action potential eventually will degrade.
b. During the "falling" phase, K+ permeability increases.
c. During the "rising" phase, Na+ moves into the neuron.
d. In the recovery phase, Na+ channels are closed.
Which statement regarding cardiac pacemaker cells is false?
a. They spontaneously generate action potentials.
b. The frequency of action potential generation can be modified by neural input.
c. The pacemaker cells are modified neural tissue.
d. They are connected to myocardium via gap junctions.
A decrease in the absolute value of the membrane potential toward zero is called
b. an action potential.
d. a membrane potential.
In a typical neuron, which ion is in passive equilibrium across the cell membrane?
d. Both Na+ and K+
A stimulating depolarizing current that depolarizes the axon hillock just slightly negative to the threshold will
a. not change the overall membrane potential at all.
b. produce an action potential.
c. produce a very small action potential.
d. produce a temporary graded potential.
The plasma membrane of a resting neuron is most permeable to which ion?
Considering the cycle of an action potential, when is the permeability to K+ at its greatest?
a. During the resting membrane potential
b. During the rising phase of the action potential
c. At the peak of the action potential
d. During the falling phase of the action potential
Which character of neurons affects conduction velocity the least?
a. Axon diameter
c. Axon length
_______ channels govern the generation of an action potential.
a. Ligand-gated Na+
b. Ligand-gated K+
c. Voltage-gated Na+
d. Voltage-gated K+
Which term best describes the movement of ions across a membrane?
If the same nerve is stimulated repeatedly and rapidly, the resultant EPSPs combine in a process called
Simultaneously occurring EPSPs produced by different nerves combine in a process called
G-protein coupled receptors are
response after repeated stimulation from fewer open calcium channels and less neurotransmitter release.
of response after second novel or noxious stimulus from increased open calcium channels and more neurotransmitter release.
more successful synapses
Repeated stimuli at glutamate receptors in the hippocampus can result in more successful synapses.
Which statement about the neuromuscular junction ACh receptor is
a. The probability an ACh channel will open depends on ACh concentration.
b. The synaptic current is the sum of the net ionic currents though all activated ACh receptors.
c. The opening of the ACh receptor is all-or-none.
d. The probability that an ACh channel will open depends on membrane voltage.
What is the mechanistic explanation for sensitization?
a. Increase in sodium flux.
b. Increase in potassium flux.
c. Decrease in potassium flux.
d. Increase in calcium flux.
The limiting factor in the synthesis of acetylcholine is the speed at which
a. acetyl groups are formed.
b. vesicles are formed.
c. choline is recycled.
d. vesicles release choline.
c. simultaneously excitatory and inhibitory.
d. either excitatory or inhibitory.
Which statement regarding chemical synapses is true?
a. Chemical synapses are only excitatory.
b. Chemical synapses transmit information in two directions.
c. Chemical synapses have high plasticity.
d. Pre- and postsynaptic currents are always similar.
Which statement best describes long-term potentiation?
a. More sodium entering the postsynaptic membrane per presynaptic action potential.
b. More neurotransmitter released per action potential.
c. More action potentials sent per second.
d. More calcium released per action potential.
What effect would injecting a leg muscle with a drug that binds to and disables acetylcholinesterase have on that leg?
a. Delayed paralysis
b. Immediate tetany
c. Tetany once the leg muscle was contracted
d. Paralysis once the leg muscle was contracted
The induction of long-term potentiation occurs in the
a. presynaptic neuron.
c. postsynaptic neuron.
d. motor neuron.
During presynaptic inhibition, a(n)
a. metabotropic response reduces the number of action potentials reaching the synapse.
b. metabotropic response reduces the amount of calcium entering the nerve terminus.
c. ionotropic response reduces the number of action potentials reaching the synapse.
d. ionotropic response reduces the amount of calcium entering the nerve terminus.
Sensory receptor is also the primary afferent neuron
Change in membrane potential spreads along membrane
Sensory receptor is separate from the afferent neuron
Change in membrane potential triggers release of neurotransmitter
action potential frequency decreases if stimulus intensity is maintained at the same level
• Produce action potentials as long as the stimulus continues.
• Encode duration of stimulus.
• Response decreases slowly or incompletely.
• Train of impulses continues during a prolonged stimulus.
• Produce action potentials at the beginning or end of the stimulus.
• The impulse train ceases during a prolonged stimulus.
• Encode change in stimulus, but not stimulus duration.
• Results in a rapidly decreasing response to a maintained stimulus.
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