APHY 201 QUIZ 2 QUESTIONS WITH VERIFIED
ANSWER
Which of the following factors is associated with increased conduction velocity in an
axon?
A. Large diameter
B. Small diameter
C. Increased number of dendrites
D. The absence of the myelin sheath
E. Presence of collaterals - Answers - A. Large diameter
The hyperpolarization phase of the AP is caused by too much ________ leaving the
cell.
A. Ca2+
B. Water
C. Na+
D. K+ - Answers - D. K+
Which of the following is NOT a characteristic of neurons?
A. In general, neurons cannot be replaced if destroyed
B. Neurons are relatively small, simple-structured cells
C. Neurons can function optimally for over 100 years
D. Neurons require continuous and abundant supplies of oxygen, and cannot survive for
more than a few minutes without it - Answers - B. Neurons are relatively small, simple-
structured cells
Which of the following is characteristic of an action potential?
A. Travels a short distance
B. Absent of positive feedback
C. Voltage-gated ion channels
D. Occurs in the dendrites and cell body - Answers - C. Voltage-gated ion channels
The principal cause of depolarization of a nerve fiber when threshold is reached is
A. An increase in the outward conductance of Na+
B. An increase in the inward conductance of Na+
C. A decrease in the inward conductance of Na+
D. An increase in the inward conductance of K+ - Answers - B. An increase in the
inward conductance of Na+
Excitatory postsynaptic potentials occur when a neurotransmitter engages a
postsynaptic membrane receptor resulting in the membrane:
A. Becoming less permeable to Na+ in
B. Becoming more permeable to K+ out
, C. Becoming more permeable to Na+ in
D. Becoming more permeable to Cl- in - Answers - C. Becoming more permeable to
Na+ in
What is the direction of the driving forces for the movement of sodium ions at the peak
of the action potential spike?
A. Outward electrical gradient and outward chemical gradient
B. Outward electrical gradient and inward chemical gradient
C. Inward electrical gradient and inward chemical gradient
D. Outward chemical gradient and outward electrical gradient - Answers - B. Outward
electrical gradient and inward chemical gradient
Which of the following membrane ion channels in the neuron are always open?
A. Mechanically gated channels
B. Ligand-gated channels
C. Voltage-gated channels
D. Leakage channels - Answers - D. Leakage channels
The resting membrane potential of a neuron is dependent on:
A. Active transport of potassium ions out of the cell
B. The opening of electrically operated sodium channel gates
C. Active transport of sodium ions into the cell
D. The presence of non-diffusible anions inside the cell - Answers - D. The presence of
non-diffusible anions inside the cell
Which of the following statements best describes the resting membrane state in the
neuron?
A. Only the voltage-gated K+ channels are open
B. All of the voltage-gated Na+ and K+ channels are closed
C. Only the voltage-gated Na+ channels are open
D. Only the voltage-gated K+ are closed
E. Only the voltage-gated Na+ channels are closed - Answers - B. All of the voltage-
gated Na+ and K+ channels are closed
According to the "all-or-none" law:
A. Either all of the fibers in a nerve are active at the same time or none of them are
B. Action potential amplitude for a given neuron is constant
C. Saltatory conduction is faster
D. The stronger the stimulus the greater the amplitude of the action potential - Answers
- B. Action potential amplitude for a given neuron is constant
A nerve fiber has a RMP of -80 mV and a threshold potential of -60 mV. Which of the
following is most likely to generate an action potential?
A. - 15 mV IPSP and - 20 mV IPSP
B. + 15 mV EPSP and + 5 mV EPSP
C. - 20 mV IPSP and + 5 mV EPSP
ANSWER
Which of the following factors is associated with increased conduction velocity in an
axon?
A. Large diameter
B. Small diameter
C. Increased number of dendrites
D. The absence of the myelin sheath
E. Presence of collaterals - Answers - A. Large diameter
The hyperpolarization phase of the AP is caused by too much ________ leaving the
cell.
A. Ca2+
B. Water
C. Na+
D. K+ - Answers - D. K+
Which of the following is NOT a characteristic of neurons?
A. In general, neurons cannot be replaced if destroyed
B. Neurons are relatively small, simple-structured cells
C. Neurons can function optimally for over 100 years
D. Neurons require continuous and abundant supplies of oxygen, and cannot survive for
more than a few minutes without it - Answers - B. Neurons are relatively small, simple-
structured cells
Which of the following is characteristic of an action potential?
A. Travels a short distance
B. Absent of positive feedback
C. Voltage-gated ion channels
D. Occurs in the dendrites and cell body - Answers - C. Voltage-gated ion channels
The principal cause of depolarization of a nerve fiber when threshold is reached is
A. An increase in the outward conductance of Na+
B. An increase in the inward conductance of Na+
C. A decrease in the inward conductance of Na+
D. An increase in the inward conductance of K+ - Answers - B. An increase in the
inward conductance of Na+
Excitatory postsynaptic potentials occur when a neurotransmitter engages a
postsynaptic membrane receptor resulting in the membrane:
A. Becoming less permeable to Na+ in
B. Becoming more permeable to K+ out
, C. Becoming more permeable to Na+ in
D. Becoming more permeable to Cl- in - Answers - C. Becoming more permeable to
Na+ in
What is the direction of the driving forces for the movement of sodium ions at the peak
of the action potential spike?
A. Outward electrical gradient and outward chemical gradient
B. Outward electrical gradient and inward chemical gradient
C. Inward electrical gradient and inward chemical gradient
D. Outward chemical gradient and outward electrical gradient - Answers - B. Outward
electrical gradient and inward chemical gradient
Which of the following membrane ion channels in the neuron are always open?
A. Mechanically gated channels
B. Ligand-gated channels
C. Voltage-gated channels
D. Leakage channels - Answers - D. Leakage channels
The resting membrane potential of a neuron is dependent on:
A. Active transport of potassium ions out of the cell
B. The opening of electrically operated sodium channel gates
C. Active transport of sodium ions into the cell
D. The presence of non-diffusible anions inside the cell - Answers - D. The presence of
non-diffusible anions inside the cell
Which of the following statements best describes the resting membrane state in the
neuron?
A. Only the voltage-gated K+ channels are open
B. All of the voltage-gated Na+ and K+ channels are closed
C. Only the voltage-gated Na+ channels are open
D. Only the voltage-gated K+ are closed
E. Only the voltage-gated Na+ channels are closed - Answers - B. All of the voltage-
gated Na+ and K+ channels are closed
According to the "all-or-none" law:
A. Either all of the fibers in a nerve are active at the same time or none of them are
B. Action potential amplitude for a given neuron is constant
C. Saltatory conduction is faster
D. The stronger the stimulus the greater the amplitude of the action potential - Answers
- B. Action potential amplitude for a given neuron is constant
A nerve fiber has a RMP of -80 mV and a threshold potential of -60 mV. Which of the
following is most likely to generate an action potential?
A. - 15 mV IPSP and - 20 mV IPSP
B. + 15 mV EPSP and + 5 mV EPSP
C. - 20 mV IPSP and + 5 mV EPSP
