Anatomy & Physiology I EXAM 3
Why does repolarization occur? - correct answer potassium ions continue to diffuse out of the cell
after the inactivation gates of the voltage-gated sodium ion channels begin to close.
Which of the following statements about the resting membrane potential is true?
a. The exterior of the cell has a net positive charge and the interior is neutral
b. The exterior of the cell has a net negative charge and the interior has a net positive charge
c. The exterior of the cell has a net positive charge and the interior has a net negative charge
d. The exterior of the cell has a net negative charge and interior is neutral
e. The exterior of the cell is neutral, and the interior has a net negative charge - correct answer The
exterior of the cell has a net positive charge and the interior has a net negative charge
During depolarization, which of the following statements about voltage-gated ions is true?
a. K+ gates open before Na+ gates
b. K+ gates open while Na+ gates remain closed
c. Na+ and K+ gates open at the same time
d. Na+ gates open before K+ gates - correct answer Na+ gates open before K+ gates
Assume all of the presynaptic synapses identified produce EPSPs. If two of these synapses fired
simultaneously, which synaptic combination brings the initial segment closest to threshold based on
spatial summation? Click on the appropriate synapses. - correct answer 3, 4
An action potential arriving at the presynaptic terminal causes what to occur? - correct answer
Voltage-gated calcium ion channels open, and calcium ions diffuse into the cell
Acetylcholine has which effect on the post-synaptic neuron? - correct answer Ligand gated sodium
ion channels open and sodium diffuse in
Graded potentials are produced within the ______ segment of a neuron - correct answer receptive
Graded potentials result from the opening of ________ - correct answer ligand-gated channels
,When voltage-gated sodium channels are open, sodium flows _____ the neuron making the inside of
the cell more ______ - correct answer into; positive
The following information best describes the ______ phase of an action potential
- a membrane potential reading of +10mV
- inactivated voltage-gated sodium channels
- open voltage-gated potassium channels - correct answer repolarization
Labeled Neuron - correct answer
What happens as a result of ion flow at a presynaptic terminal? - correct answer Synaptic vesicles
migrate to the plasma membrane and release acetylcholine
The primary neurotransmitter at the neuromuscular junction is ______. - correct answer
acetylcholine
Arrange the following in the order in which they occur at the postsynaptic side of a neuromuscular
junction:
1. An action potential is progated over the muscle cell membrane
2. Depolarization of the postsynaptic membrane
3. Sodium ions move into muscle cell - correct answer 3, 2, 1
Hyperpolarization - correct answer
Resting - correct answer
Repolarization - correct answer
Depolarization - correct answer
Action potentials occur _______ - correct answer in the unmyelinated regions of an axon
, Demyelinating diseases cause a(n) ____ in the conduction velocity of action potentials - correct
answer decrease
If demyelination occurs, why don't action potentials occur at regions of the axon that were
previously myelinated? - correct answer These regions lack the appropriate concentration of
voltage-gated sodium channels
Which of the following statements about the resting membrane potential is true?
a. The exterior of the cell has a net positive charge and the interior is neutral
b. The exterior of the cell has a net negative charge and the interior is neutral
c. The exterior of the cell is neutral, and the interior has a negative charge
d. The exterior of the cell has a net negative charge and the interior has a net positive charge
e. The exterior of the cell has a net positive charge and the interior has a net negative charge -
correct answer e
Why does depolarization occur? - correct answer more Na+ diffuse into the cell than K+ diffuse out
of it
At the synaptic knob, voltage-gated _____ channels open, thereby stimulating the synaptic vesicles
to release their neurotransmitters by exocytosis - correct answer calcium
If acetylcholinesterase became mutated and nonfunctional, what would be the immediate result? -
correct answer acetylcholine would build up in the synaptic cleft
If a drug was developed that interfered with the proper functioning of the microtubules found within
the axons of neurons, how would you expect this to impact axonal transport processes? - correct
answer Both anterograde and retrograde transport processes would cease
The enzyme choline acetyltransferase catalyzes the reaction between acetyl-CoA and choline
resulting in the formation of the neurotransmitter acetylcholine. This enzyme is produced within the
cell body of neurons, but the synthesis of acetylcholine occurs within the axon terminals. Which
statement best describes the axonal transport mechanism associated with this process? - correct
answer Choline acetyltransferase is transported in the anterograde direction
Why does repolarization occur? - correct answer potassium ions continue to diffuse out of the cell
after the inactivation gates of the voltage-gated sodium ion channels begin to close.
Which of the following statements about the resting membrane potential is true?
a. The exterior of the cell has a net positive charge and the interior is neutral
b. The exterior of the cell has a net negative charge and the interior has a net positive charge
c. The exterior of the cell has a net positive charge and the interior has a net negative charge
d. The exterior of the cell has a net negative charge and interior is neutral
e. The exterior of the cell is neutral, and the interior has a net negative charge - correct answer The
exterior of the cell has a net positive charge and the interior has a net negative charge
During depolarization, which of the following statements about voltage-gated ions is true?
a. K+ gates open before Na+ gates
b. K+ gates open while Na+ gates remain closed
c. Na+ and K+ gates open at the same time
d. Na+ gates open before K+ gates - correct answer Na+ gates open before K+ gates
Assume all of the presynaptic synapses identified produce EPSPs. If two of these synapses fired
simultaneously, which synaptic combination brings the initial segment closest to threshold based on
spatial summation? Click on the appropriate synapses. - correct answer 3, 4
An action potential arriving at the presynaptic terminal causes what to occur? - correct answer
Voltage-gated calcium ion channels open, and calcium ions diffuse into the cell
Acetylcholine has which effect on the post-synaptic neuron? - correct answer Ligand gated sodium
ion channels open and sodium diffuse in
Graded potentials are produced within the ______ segment of a neuron - correct answer receptive
Graded potentials result from the opening of ________ - correct answer ligand-gated channels
,When voltage-gated sodium channels are open, sodium flows _____ the neuron making the inside of
the cell more ______ - correct answer into; positive
The following information best describes the ______ phase of an action potential
- a membrane potential reading of +10mV
- inactivated voltage-gated sodium channels
- open voltage-gated potassium channels - correct answer repolarization
Labeled Neuron - correct answer
What happens as a result of ion flow at a presynaptic terminal? - correct answer Synaptic vesicles
migrate to the plasma membrane and release acetylcholine
The primary neurotransmitter at the neuromuscular junction is ______. - correct answer
acetylcholine
Arrange the following in the order in which they occur at the postsynaptic side of a neuromuscular
junction:
1. An action potential is progated over the muscle cell membrane
2. Depolarization of the postsynaptic membrane
3. Sodium ions move into muscle cell - correct answer 3, 2, 1
Hyperpolarization - correct answer
Resting - correct answer
Repolarization - correct answer
Depolarization - correct answer
Action potentials occur _______ - correct answer in the unmyelinated regions of an axon
, Demyelinating diseases cause a(n) ____ in the conduction velocity of action potentials - correct
answer decrease
If demyelination occurs, why don't action potentials occur at regions of the axon that were
previously myelinated? - correct answer These regions lack the appropriate concentration of
voltage-gated sodium channels
Which of the following statements about the resting membrane potential is true?
a. The exterior of the cell has a net positive charge and the interior is neutral
b. The exterior of the cell has a net negative charge and the interior is neutral
c. The exterior of the cell is neutral, and the interior has a negative charge
d. The exterior of the cell has a net negative charge and the interior has a net positive charge
e. The exterior of the cell has a net positive charge and the interior has a net negative charge -
correct answer e
Why does depolarization occur? - correct answer more Na+ diffuse into the cell than K+ diffuse out
of it
At the synaptic knob, voltage-gated _____ channels open, thereby stimulating the synaptic vesicles
to release their neurotransmitters by exocytosis - correct answer calcium
If acetylcholinesterase became mutated and nonfunctional, what would be the immediate result? -
correct answer acetylcholine would build up in the synaptic cleft
If a drug was developed that interfered with the proper functioning of the microtubules found within
the axons of neurons, how would you expect this to impact axonal transport processes? - correct
answer Both anterograde and retrograde transport processes would cease
The enzyme choline acetyltransferase catalyzes the reaction between acetyl-CoA and choline
resulting in the formation of the neurotransmitter acetylcholine. This enzyme is produced within the
cell body of neurons, but the synthesis of acetylcholine occurs within the axon terminals. Which
statement best describes the axonal transport mechanism associated with this process? - correct
answer Choline acetyltransferase is transported in the anterograde direction
