BIO 235 Final Exam | Dr. MacDonald WOU | Questions and Answers |
2024 update
Potassium:
A. is more abundant outside the cell than inside the cell.
B. moves into the cell during an action potential.
C. is transported out of the neuron by the sodium-potassium pump.
D. leaks out of the cell more than sodium leaks into the cell. ** Answ** c.
salutary and continuous action potential conduction ** Answ** conduction occurs in
myelinated axons. Nerve signals transmit much faster than in continuous conduction
because an action potential is generated only at the neurofibrils (segments of axon
without myelination) of myelinated axon rather than along the entire length of
unmyelinated axon.
EPSP ** Answ** Excitatory postsynaptic potential; a slight depolarization of a
postsynaptic cell, bringing the membrane potential of that cell closer to the threshold for
an action potential.
Spacial and temporal summation ** Answ** summation in axon hillock of post
synaptic potentials across the cell body, summation of potentials that reach the axon
hillock at different times, closer in time, more complete the summation
An action potential reaches the synaptic terminal of a presynaptic cell. How does this
message get transmitted to the postsynaptic cell? Please only describe what is
happening at the location where this message transfer occurs, but be sure to include all
relevant chemicals and parts of the cell involved. ** Answ** When an action
potential reaches the axon terminal it depolarizes the membrane and opens voltage-
,gated Na+ channels. Na+ ions enter the cell, further depolarizing the presynaptic
membrane
In a cross section of the spinal chord the areas that are grey are
(a)___________________________ neurons and the areas that are white are called
_____________________ neurons ** Answ** The gray matter is made up of
neuroglia cells and neuron cell bodies. The white matter is made up of neuron axons,
mostly but not all myelinated.
(Using the figure/graph) Which of the following is happening during the period indicated
by the number 2 on the graph?
A. There is no ion movement during this period.
B. chloride is entering the neuron through chemically-gated channels.
C. potassium is leaving the neuron through voltage-gated channels.
D. sodium is entering the neuron through voltage-gated channels. ** Answ** sodium
is entering the neuron through voltage-gated channels.
A strong stimulus coming into a dendrite of a multipolar neuron will cause a strong
graded potential to be generated.
True
False ** Answ** true
Myelin Sheaths in the PNS:
a. Increases speed of action potentials
b. Protects and electrically insulates neurons from one another
c. All of the answers are correct
d. Concentric layers of Schwann cells membrane
e. None of the answers are correct ** Answ** All of the above
, Where would you find sodium-potassium pumps and leak channels on a neuron?
A. cell body only
B. synaptic terminal only
C. entire neuron cell membrane
D. axon only
E. dendrites only ** Answ** A. cell body only
An IPSP:
A. is caused by a chemically-gated sodium channel opening.
B. hyperpolarizes the post-synaptic cell pushing it farther from threshold.
C. is a graded depolarization of the post-synaptic cell.
D. is an excitatory stimulus bringing the neuron closer to an action potential. ** Answ**
B. hyperpolarizes the post-synaptic cell pushing it farther from threshold
Are the first channels opened when -55mV is reached at the axon hillock. ** Answ**
Voltage-gated sodium channels
Cause the transmembrane potential to maintain a relatively stable state of -70mV. **
Answ**
Cause a graded depolarization to occur on the cell body and dendrites. ** Answ**
Cause the transmembrane potential to go from +30mV to about -90 mV. ** Answ**
Cause synaptic vesicles to migrate to the cell membrane at the synaptic terminal. **
Answ** calcium
produce myelination in the peripheral nervous system (PNS) neurons.
2024 update
Potassium:
A. is more abundant outside the cell than inside the cell.
B. moves into the cell during an action potential.
C. is transported out of the neuron by the sodium-potassium pump.
D. leaks out of the cell more than sodium leaks into the cell. ** Answ** c.
salutary and continuous action potential conduction ** Answ** conduction occurs in
myelinated axons. Nerve signals transmit much faster than in continuous conduction
because an action potential is generated only at the neurofibrils (segments of axon
without myelination) of myelinated axon rather than along the entire length of
unmyelinated axon.
EPSP ** Answ** Excitatory postsynaptic potential; a slight depolarization of a
postsynaptic cell, bringing the membrane potential of that cell closer to the threshold for
an action potential.
Spacial and temporal summation ** Answ** summation in axon hillock of post
synaptic potentials across the cell body, summation of potentials that reach the axon
hillock at different times, closer in time, more complete the summation
An action potential reaches the synaptic terminal of a presynaptic cell. How does this
message get transmitted to the postsynaptic cell? Please only describe what is
happening at the location where this message transfer occurs, but be sure to include all
relevant chemicals and parts of the cell involved. ** Answ** When an action
potential reaches the axon terminal it depolarizes the membrane and opens voltage-
,gated Na+ channels. Na+ ions enter the cell, further depolarizing the presynaptic
membrane
In a cross section of the spinal chord the areas that are grey are
(a)___________________________ neurons and the areas that are white are called
_____________________ neurons ** Answ** The gray matter is made up of
neuroglia cells and neuron cell bodies. The white matter is made up of neuron axons,
mostly but not all myelinated.
(Using the figure/graph) Which of the following is happening during the period indicated
by the number 2 on the graph?
A. There is no ion movement during this period.
B. chloride is entering the neuron through chemically-gated channels.
C. potassium is leaving the neuron through voltage-gated channels.
D. sodium is entering the neuron through voltage-gated channels. ** Answ** sodium
is entering the neuron through voltage-gated channels.
A strong stimulus coming into a dendrite of a multipolar neuron will cause a strong
graded potential to be generated.
True
False ** Answ** true
Myelin Sheaths in the PNS:
a. Increases speed of action potentials
b. Protects and electrically insulates neurons from one another
c. All of the answers are correct
d. Concentric layers of Schwann cells membrane
e. None of the answers are correct ** Answ** All of the above
, Where would you find sodium-potassium pumps and leak channels on a neuron?
A. cell body only
B. synaptic terminal only
C. entire neuron cell membrane
D. axon only
E. dendrites only ** Answ** A. cell body only
An IPSP:
A. is caused by a chemically-gated sodium channel opening.
B. hyperpolarizes the post-synaptic cell pushing it farther from threshold.
C. is a graded depolarization of the post-synaptic cell.
D. is an excitatory stimulus bringing the neuron closer to an action potential. ** Answ**
B. hyperpolarizes the post-synaptic cell pushing it farther from threshold
Are the first channels opened when -55mV is reached at the axon hillock. ** Answ**
Voltage-gated sodium channels
Cause the transmembrane potential to maintain a relatively stable state of -70mV. **
Answ**
Cause a graded depolarization to occur on the cell body and dendrites. ** Answ**
Cause the transmembrane potential to go from +30mV to about -90 mV. ** Answ**
Cause synaptic vesicles to migrate to the cell membrane at the synaptic terminal. **
Answ** calcium
produce myelination in the peripheral nervous system (PNS) neurons.
