NEUROBIOLOGY EXAM 1 QUESTIONS
AND ANSWERS
The resting membrane potential of the neuron is about -70 mV. This is close to the
equilibrium potential of which ion? - Correct Answers -Potassium (K+)
The length constant (λ) will be greater in a neuron with a: - Correct Answers -large
membrane resistance (Rm)
An axon potential is initialed at the axon hillock. Besides occurring in a different location,
what is the difference between an excitatory postsynaptic potential (EPSP) and an
action potential? - Correct Answers -Once the depolarization in voltage reaches a
threshold, the action potential depolarizes rapidly in an all or nothing manner, whereas
an EPSP is only a change in depolarization.
With regard to movement of ions and the Nernst equation: - Correct Answers -If the
measured membrane potential equals the value calculated using the Nernst equation
then there will be no net movement of that ion.
Functionally, the presence of myelin around an axon: - Correct Answers -increases the
conduction velocity of action potentials in that axon.
A dendritic membrane with a large time constant (τ) and a small length constant (λ) will
allow a postsynaptic potential to decay: - Correct Answers -slowly, but spread only a
short distance.
Myelin - Correct Answers -Neurons with more myelin can send info faster and over
longer distancesq
What is saltatory conduction - Correct Answers -Charging the nearby membrane and
opening ion channels takes time
Action potentials can occur where myelin covers axon
What are the nodes of Ranvier - Correct Answers -Gaps are close enough so voltage-
sensitive gates can be triggered on next node
Be able to describe Otto Loewi's experiment & know its contribution to the description of
synaptic transmission - Correct Answers -Frog heart experiment, discovered first NT
acetylcholine, signaling across a synapse is chemical
, While Dr. Huxley is recording the activity of a squid axon, he finds that a larger
depolarizing shock is necessary on occasion in order to produce a new action potential.
What is the most likely explanation for Dr. Huxley's observations? - Correct Answers -
Dr. Huxley's second shock probably occurs during a relative refractory period.
Ignoring constants, it is accurate to say that the Goldman-Hodgkin-Katz (GHK) equation
allows you to calculate the: - Correct Answers -membrane potential for a neuron, based
on the concentrations and permeabilities of the major ions.
During the depolarizing (rising) phase of an action potential the current flow is
dominated by an: - Correct Answers -inward sodium (Na+) current.
In general, flow of information in a neuron occurs in the following manner: - Correct
Answers -Signals are received at the dendrites, processed in the cell body, and passed
to other neurons via the axon.
Which of the following is NOT an important factor in the generation of and recovery from
an action potential in a squid giant axon? - Correct Answers -The influx of calcium
(Ca2+)
What does the Neuron Doctrine state? - Correct Answers -The elementary functional
unit of the nervous system is the neuron.
As you study for your Neurobiology exam, you feel a tickle on your arm. You look a see
a large cockroach and you jerk your arm automatically. What is the neural pathway for
this action. - Correct Answers -Sensory neuron - interneuron - motor neuron - muscle
When a neuron is at resting potential which of the following is the correct distribution of
ions inside and outside of its membrane? - Correct Answers -K+ ions and large protein
molecules inside, Na+ and Cl- ions outside
Near the peak of an action potential, which ion begins to leave the cell? - Correct
Answers -Potassium (K+)
A neuron is unable to produce another action potential under any circumstances during
the - Correct Answers -absolute refractory period.
Which of the following is most likely to result in the generation of an action potential? -
Correct Answers -Several excitatory postsynaptic potentials (EPSPs) that occur
simultaneously and occur on the same dendritic spine.
In response to stimulation ___ or ___ channels may open producing an inhibitory
postsynaptic potential (IPSP). - Correct Answers -Cl-; potassium (K+)
AND ANSWERS
The resting membrane potential of the neuron is about -70 mV. This is close to the
equilibrium potential of which ion? - Correct Answers -Potassium (K+)
The length constant (λ) will be greater in a neuron with a: - Correct Answers -large
membrane resistance (Rm)
An axon potential is initialed at the axon hillock. Besides occurring in a different location,
what is the difference between an excitatory postsynaptic potential (EPSP) and an
action potential? - Correct Answers -Once the depolarization in voltage reaches a
threshold, the action potential depolarizes rapidly in an all or nothing manner, whereas
an EPSP is only a change in depolarization.
With regard to movement of ions and the Nernst equation: - Correct Answers -If the
measured membrane potential equals the value calculated using the Nernst equation
then there will be no net movement of that ion.
Functionally, the presence of myelin around an axon: - Correct Answers -increases the
conduction velocity of action potentials in that axon.
A dendritic membrane with a large time constant (τ) and a small length constant (λ) will
allow a postsynaptic potential to decay: - Correct Answers -slowly, but spread only a
short distance.
Myelin - Correct Answers -Neurons with more myelin can send info faster and over
longer distancesq
What is saltatory conduction - Correct Answers -Charging the nearby membrane and
opening ion channels takes time
Action potentials can occur where myelin covers axon
What are the nodes of Ranvier - Correct Answers -Gaps are close enough so voltage-
sensitive gates can be triggered on next node
Be able to describe Otto Loewi's experiment & know its contribution to the description of
synaptic transmission - Correct Answers -Frog heart experiment, discovered first NT
acetylcholine, signaling across a synapse is chemical
, While Dr. Huxley is recording the activity of a squid axon, he finds that a larger
depolarizing shock is necessary on occasion in order to produce a new action potential.
What is the most likely explanation for Dr. Huxley's observations? - Correct Answers -
Dr. Huxley's second shock probably occurs during a relative refractory period.
Ignoring constants, it is accurate to say that the Goldman-Hodgkin-Katz (GHK) equation
allows you to calculate the: - Correct Answers -membrane potential for a neuron, based
on the concentrations and permeabilities of the major ions.
During the depolarizing (rising) phase of an action potential the current flow is
dominated by an: - Correct Answers -inward sodium (Na+) current.
In general, flow of information in a neuron occurs in the following manner: - Correct
Answers -Signals are received at the dendrites, processed in the cell body, and passed
to other neurons via the axon.
Which of the following is NOT an important factor in the generation of and recovery from
an action potential in a squid giant axon? - Correct Answers -The influx of calcium
(Ca2+)
What does the Neuron Doctrine state? - Correct Answers -The elementary functional
unit of the nervous system is the neuron.
As you study for your Neurobiology exam, you feel a tickle on your arm. You look a see
a large cockroach and you jerk your arm automatically. What is the neural pathway for
this action. - Correct Answers -Sensory neuron - interneuron - motor neuron - muscle
When a neuron is at resting potential which of the following is the correct distribution of
ions inside and outside of its membrane? - Correct Answers -K+ ions and large protein
molecules inside, Na+ and Cl- ions outside
Near the peak of an action potential, which ion begins to leave the cell? - Correct
Answers -Potassium (K+)
A neuron is unable to produce another action potential under any circumstances during
the - Correct Answers -absolute refractory period.
Which of the following is most likely to result in the generation of an action potential? -
Correct Answers -Several excitatory postsynaptic potentials (EPSPs) that occur
simultaneously and occur on the same dendritic spine.
In response to stimulation ___ or ___ channels may open producing an inhibitory
postsynaptic potential (IPSP). - Correct Answers -Cl-; potassium (K+)
