Threshold stimuli are those that are strong enough to:
1. Hyperpolarize the neuron membrane
2. Cause a net flux of negatively charged ions from inside to outside the cell
3. Cause a net flux of positively charged ions from outside to inside the cell
4. Close calcium channels to retain them in the cell

Subtopic:  Action Potential |
 69%

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The period of time during which a second action potential cannot be initiated, no matter how large the applied stimulus is the absolute refractory period. Which statement is true for this period?

1. Potassium channels are open and the membrane is hyperpolarized
2. It immediately follows the relative refractory period
3. It allows an action potential to proceed in two directions along the length of an axon
4. It occurs when the sodium channels are open

Subtopic:  Origin of Resting Membrane Potential | Action Potential |

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All the following statements with respect to the propagation of action potentials are correct except:
1. Saltatory conduction occurs in myelinated nerve fibers
2. During conduction of an action potential, current flows from the active area of the membrane to the adjacent inactive area, thereby decreasing the potential in the inactive area to the threshold
3. Action potential propagation is faster in myelinated fibers than in unmyelinated ones
4. Action potential propagation is faster for strong stimuli than for weaker stimuli

Subtopic:  Origin of Resting Membrane Potential | Action Potential |
 59%
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An Inhibitory Post-Synaptic Potential:
1. causes depolarization
2. is caused by an increase in the permeability of the postsynaptic membrane to potassium or chloride ions
3. causes repolarization
4. is caused by an increase in the permeability of the postsynaptic membrane to sodium ions

Subtopic:  Synapse |
 53%

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Common inhibitory neurotrnasmitters in brain and spinal cord are:

1. Glutamate
2. GABA (gamma-amino-butyric aci4.
3. Glutamate and glycine
4. GABA (gamma-amino-butyric acid and glycine

Subtopic:  Synapse |
 50%

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The blood–brain barrier (BBB) separates the circulating blood from the brain and extracellular fluid in the central nervous system (CNS) and:

1. Functions to control the exchange of substances between blood and the extracellular fluid in the CNS

2. Is comprised of the cells that line the largest blood vessels in the brain

3. Is comprised of the cells that line the ventricles of the brain

4. Prevents diffusion of lipid soluble molecules from the blood to the brain

Subtopic:  Nervous System |
 63%

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In the peripheral nervous system, the cells that are capable of forming a regeneration tube through which a severed peripheral axon can regrow are the:

1. Schwann cells
2. astrocytes
3. oligodendrocytes
4. microglia

Subtopic:  Nervous System |
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The relatively static membrane potential of quiescent cells is called the:

1. action potential 2. threshold potential
3. resting membrane potential 4. graded potential
Subtopic:  Origin of Resting Membrane Potential |
 74%
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All the following statements regarding the action potential are true except:
1. Only a relatively small number of Na+ and K+ ions actually diffuse across the membrane.
2. This event includes both positive and negative feedback loops.
3. The Na+/K+ pumps are directly involved in creating the action potential.
4. During an action potential, the Na+ and K+ total concentration are not significantly changed.

Subtopic:  Origin of Resting Membrane Potential | Action Potential |
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A local anesthetic is a medication that causes reversible absence of pain sensation. They:
1. block the closure of voltage regulated potassium ion channels
2. stimulate the opening of voltage regulated potassium ion channels
3. block the opening of the voltage regulated sodium ion channels
4. stimulate the opening of voltage regulated sodium ion channels

Subtopic:  Action Potential |
 67%

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