Section II: Neurophysiology Flashcards
Which part of a neuron is primarily characterized as the information-receiving component?
a. Axon
b. Presynaptic terminal
c. Cell body
d. Dendrite
e. Myelin
Which part of a neuron is primarily characterized as the information-receiving component?
a. Axon
b. Presynaptic terminal
c. Cell body
d. Dendrite
e. Myelin
Which of the following is not characteristic of glial cells?
a. Production of action potentials
b. Immune responses of the nervous system
c. Production of the myelin sheaths of axons
d. Modulating the growth of developing or damaged
neurons
e. Buffering extracellular concentrations of some ions and
neurotransmitters
Which of the following is not characteristic of glial cells?
a. Production of action potentials
b. Immune responses of the nervous system
c. Production of the myelin sheaths of axons
d. Modulating the growth of developing or damaged
neurons
e. Buffering extracellular concentrations of some ions and
neurotransmitters
The elements of spinal and cranial nerves that carry action potential commands from the CNS to synapses at skeletal
muscles are:
a. Axons of visceral efferent neurons
b. Axons of somatic afferent neurons
c. Axons of somatic efferent neurons
d. The dorsal roots
e. Axons of visceral afferent neurons
The elements of spinal and cranial nerves that carry action potential commands from the CNS to synapses at skeletal
muscles are:
a. Axons of visceral efferent neurons
b. Axons of somatic afferent neurons
c. Axons of somatic efferent neurons
d. The dorsal roots
e. Axons of visceral afferent neurons
The thalamus and hypothalamus are components of which major brain division?
a. Medulla
b. Pons
c. Midbrain
d. Diencephalon
e. Telencephalon
The thalamus and hypothalamus are components of which major brain division?
a. Medulla
b. Pons
c. Midbrain
d. Diencephalon
e. Telencephalon
When treating critically ill patients with intravenous fluids, which two ions are most important to the neuronal membrane potential?
a. Na+ and Cl–
b. K+ and Cl–
c. Ca2+ and Cl–
d. K+ and Ca2+
e. Na+ and K+
When treating critically ill patients with intravenous fluids, which two ions are most important to the neuronal membrane potential?
a. Na+ and Cl–
b. K+ and Cl–
c. Ca2+ and Cl–
d. K+ and Ca2+
e. Na+ and K+
The energy required by the Na+, K+ neural membrane pump is derived from ATP. In the neuron, this energy results from the nearly exclusive metabolism of oxygen and:
a. Amino acids
b. Fatty acids
c. Glucose
d. Glycogen
e. Proteins
The energy required by the Na+, K+ neural membrane pump is derived from ATP. In the neuron, this energy results from the nearly exclusive metabolism of oxygen and:
a. Amino acids
b. Fatty acids
c. Glucose
d. Glycogen
e. Proteins
If the number of IPSPs on the dendritic membrane decreases while the number of EPSPs remains the same, what will happen to the action potentials on that neuron?
a. Probability of triggering action potentials increases.
b. Probability of triggering action potentials decreases.
c. Probability of triggering action potentials remains unchanged.
d. Action potentials would be eliminated.
e. Action potentials would be conducted with increased velocity
If the number of IPSPs on the dendritic membrane decreases while the number of EPSPs remains the same, what will happen to the action potentials on that neuron?
a. Probability of triggering action potentials increases.
b. Probability of triggering action potentials decreases.
c. Probability of triggering action potentials remains unchanged.
d. Action potentials would be eliminated.
e. Action potentials would be conducted with increased velocity
During an excitatory postsynaptic potential in a neural membrane, which of the following is the most important ion flow?
a. Sodium ions diffuse out of the cell.
b. Sodium ions diffuse into the cell.
c. Potassium ions diffuse out of the cell.
d. Potassium ions pumped in by the Na+, K+ pump.
e. None of the above.
During an excitatory postsynaptic potential in a neural membrane, which of the following is the most important ion flow?
a. Sodium ions diffuse out of the cell.
b. Sodium ions diffuse into the cell.
c. Potassium ions diffuse out of the cell.
d. Potassium ions pumped in by the Na+, K+ pump.
e. None of the above.
Choose the incorrect statement below:
a. Conduction velocity of action potentials is slower in myelinated than in unmyelinated axons.
b. Conduction velocity of action potentials is faster in myelinated than in unmyelinated axons.
c. In saltatory conduction of action potentials, the action potential seems to jump functionally from node to node
(nodes of Ranvier).
d. Action potentials are of equal magnitude at the beginning
and at the end of an axon.
Choose the incorrect statement below:
a. Conduction velocity of action potentials is slower in myelinated than in unmyelinated axons.
b. Conduction velocity of action potentials is faster in myelinated than in unmyelinated axons.
c. In saltatory conduction of action potentials, the action potential seems to jump functionally from node to node
(nodes of Ranvier).
d. Action potentials are of equal magnitude at the beginning
and at the end of an axon.
At the neuromuscular junction, Ca2+ ions are necessary for:
a. Binding the transmitter with the postsynaptic receptor.
b. Facilitating diffusion of the transmitter to the postsynaptic membrane.
c. Splitting the transmitter in the cleft, thus deactivating the transmitter.
d. Fusing the presynaptic vesicle with the presynaptic membrane, thus releasing the transmitter.
e. Metabolizing the transmitter within the presynaptic vesicle.
At the neuromuscular junction, Ca2+ ions are necessary for:
a. Binding the transmitter with the postsynaptic receptor.
b. Facilitating diffusion of the transmitter to the postsynaptic membrane.
c. Splitting the transmitter in the cleft, thus deactivating the transmitter.
d. Fusing the presynaptic vesicle with the presynaptic membrane, thus releasing the transmitter.
e. Metabolizing the transmitter within the presynaptic vesicle.
A drug that would prevent the release of acetylcholine at the neuromuscular junction would cause what, if any, clinical signs?
a. Convulsions and excess muscle contractions
b. Paralysis
c. No effect on an animal’s movement
A drug that would prevent the release of acetylcholine at the neuromuscular junction would cause what, if any, clinical signs?
a. Convulsions and excess muscle contractions
b. Paralysis
c. No effect on an animal’s movement
Which one of the following is true with regard to the termination of synaptic action at the neuromuscular junction?
a. The reuptake of intact acetylcholine molecules into the motor neuron terminal is responsible.
b. Diffusion of acetylcholine away from the synapse is solely responsible.
c. Acetylcholinesterase rapidly breaks down acetylcholine into choline and acetate.
d. Dissociation of acetylcholine from the muscarinic receptor, after binding for several seconds, is solely responsible.
Which one of the following is true with regard to the termination of synaptic action at the neuromuscular junction?
a. The reuptake of intact acetylcholine molecules into the motor neuron terminal is responsible.
b. Diffusion of acetylcholine away from the synapse is solely responsible.
c. Acetylcholinesterase rapidly breaks down acetylcholine into choline and acetate.
d. Dissociation of acetylcholine from the muscarinic receptor, after binding for several seconds, is solely responsible.
Several antagonist drugs compete with acetylcholine for the postsynaptic receptor at the neuromuscular junction. If you overdosed your patient with one of these competitive drugs, what would the antidote need to do at the synapse?
a. Decrease the release of acetylcholine.
b. Decrease the effectiveness of acetylcholinesterase.
c. Decrease the influx of Ca2+ into the motor neuron terminal.
d. Decrease the action potential frequency on the motor neuron.
e. None of the above
Several antagonist drugs compete with acetylcholine for the postsynaptic receptor at the neuromuscular junction. If you overdosed your patient with one of these competitive drugs, what would the antidote need to do at the synapse?
a. Decrease the release of acetylcholine.
b. Decrease the effectiveness of acetylcholinesterase.
c. Decrease the influx of Ca2+ into the motor neuron terminal.
d. Decrease the action potential frequency on the motor neuron.
e. None of the above
Which of the following statements regarding neuron-to-neuron
synapses is false?
a. The postsynaptic membrane is always a dendrite.
b. Dendritic spines increase the surface area of the postsynaptic membrane.
c. A single action potential on a presynaptic neuron is usually
not sufficient to produce an action potential on a postsynaptic neuron.
d. The neurotransmitter is not always released from a morphologically distinct active zone of the presynaptic terminal.
e. Depending on the presynaptic neurotransmitter released
and the postsynaptic receptor activated, the postsynaptic membrane can be either depolarized or hyperpolarized.
Which of the following statements regarding neuron-to-neuron
synapses is false?
a. The postsynaptic membrane is always a dendrite.
b. Dendritic spines increase the surface area of the postsynaptic membrane.
c. A single action potential on a presynaptic neuron is usually
not sufficient to produce an action potential on a postsynaptic neuron.
d. The neurotransmitter is not always released from a morphologically distinct active zone of the presynaptic terminal.
e. Depending on the presynaptic neurotransmitter released
and the postsynaptic receptor activated, the postsynaptic membrane can be either depolarized or hyperpolarized.
Troponin and tropomyosin are components of which one of the following structures?
a. Myosin thick filament
b. Sarcolemma
c. T tubule
d. Actin thin filament
e. Sarcoplasmic reticulum
Troponin and tropomyosin are components of which one of the following structures?
a. Myosin thick filament
b. Sarcolemma
c. T tubule
d. Actin thin filament
e. Sarcoplasmic reticulum
Action potentials in skeletal muscle cells trigger the release from the sarcoplasmic reticulum of what ion critical to the muscle’s contractile process?
a. Ca2+
b. Na+
c. K+
d. Cl–
e. HCO3–
Action potentials in skeletal muscle cells trigger the release from the sarcoplasmic reticulum of what ion critical to the muscle’s contractile process?
a. Ca2+
b. Na+
c. K+
d. Cl–
e. HCO3–
A gross skeletal muscle belly can be instructed (by the central
nervous system) to contract more forcefully by:
a. Causing more of its motor units to contract simultaneously.
b. Increasing the amount of acetylcholine released during each neuromuscular synaptic transmission.
c. Increasing the frequency of action potentials in the α motor
neuron’s axon.
d. Both a and c.
e. Both b and c.
A gross skeletal muscle belly can be instructed (by the central
nervous system) to contract more forcefully by:
a. Causing more of its motor units to contract simultaneously.
b. Increasing the amount of acetylcholine released during each neuromuscular synaptic transmission.
c. Increasing the frequency of action potentials in the α motor
neuron’s axon.
d. Both a and c.
e. Both b and c.
Which one of the following is not found in smooth muscle?
a. Actin filaments
b. Myosin filaments
c. T tubules
d. Voltage-gated calcium channels
e. Sarcoplasmic reticulum
Which one of the following is not found in smooth muscle?
a. Actin filaments
b. Myosin filaments
c. T tubules
d. Voltage-gated calcium channels
e. Sarcoplasmic reticulum
Choose the incorrect statement:
a. The muscle fiber and neuronal cell membranes are similar because they both have a resting membrane potential.
b. A whole muscle, such as the gastrocnemius muscle, can be
made to contract more forcefully by increasing the number
of motor units contracting.
c. The muscle membrane’s transverse tubular system transmits the action potential to the interior of the muscle cell.
d. The muscle cell membrane transmits action potentials by saltatory conduction.
e. The shortening of a skeletal muscle during contraction is caused by the sliding of actin along myosin filaments.
Choose the incorrect statement:
a. The muscle fiber and neuronal cell membranes are similar because they both have a resting membrane potential.
b. A whole muscle, such as the gastrocnemius muscle, can be
made to contract more forcefully by increasing the number
of motor units contracting.
c. The muscle membrane’s transverse tubular system transmits the action potential to the interior of the muscle cell.
d. The muscle cell membrane transmits action potentials by saltatory conduction.
e. The shortening of a skeletal muscle during contraction is caused by the sliding of actin along myosin filaments.
Which one of the following is least likely to be significantly associated with a muscle that is primarily involved in brief, powerful movements?
a. Large α motor neuron cell body
b. Small motor unit
c. Fast-twitch fibers
d. White muscle
e. Large motor unit
Which one of the following is least likely to be significantly associated with a muscle that is primarily involved in brief, powerful movements?
a. Large α motor neuron cell body
b. Small motor unit
c. Fast-twitch fibers
d. White muscle
e. Large motor unit
Which of the following is not always a component of a reflex arc?
a. Receptor
b. Sensory neuron (CNS afferent)
c. Central nervous system (CNS) interneuron
d. Motor neuron (CNS efferent)
e. Target (effector) organ
Which of the following is not always a component of a reflex arc?
a. Receptor
b. Sensory neuron (CNS afferent)
c. Central nervous system (CNS) interneuron
d. Motor neuron (CNS efferent)
e. Target (effector) organ
Which of the following regarding sensory receptors is false?
a. They transduce environmental signals, directly or indirectly, into neuronal action potentials.
b. A primary receptor can be a specialized peripheral region of a sensory neuron.
c. They directly transduce CNS action potentials into physical activity of a target organ.
d. They are the initial component of a reflex arc.
Which of the following regarding sensory receptors is false?
a. They transduce environmental signals, directly or indirectly, into neuronal action potentials.
b. A primary receptor can be a specialized peripheral region of a sensory neuron.
c. They directly transduce CNS action potentials into physical activity of a target organ.
d. They are the initial component of a reflex arc.
When the intensity with which a receptor is stimulated is increased, what happens to the frequency of action potentials
along the sensory neuron from that receptor?
a. Increases
b. Decreases
c. No change
When the intensity with which a receptor is stimulated is increased, what happens to the frequency of action potentials
along the sensory neuron from that receptor?
a. Increases
b. Decreases
c. No change
Which one of the following is an example of a segmental reflex?
a. Quadriceps stretch reflex
b. Cutaneous trunci reflex
c. Vestibulospinal postural reflexes
Which one of the following is an example of a segmental reflex?
a. Quadriceps stretch reflex
b. Cutaneous trunci reflex
c. Vestibulospinal postural reflexes
An intersegmental reflex arc is one in which:
a. The course of the arc is restricted to one or a small number
of segments of the CNS.
b. No target organ is present.
c. No receptor is present.
d. The course of the arc traverses several segments of the CNS.
e. Both b and c.
An intersegmental reflex arc is one in which:
a. The course of the arc is restricted to one or a small number
of segments of the CNS.
b. No target organ is present.
c. No receptor is present.
d. The course of the arc traverses several segments of the CNS.
e. Both b and c.
If the distance between the origin and insertion tendons is increased (the muscle is stretched), what happens to the frequency of action potentials along the sensory axons leaving the muscle
spindles in that muscle?
a. Increases
b. Decreases
c. Does not change
If the distance between the origin and insertion tendons is increased (the muscle is stretched), what happens to the frequency of action potentials along the sensory axons leaving the muscle
spindles in that muscle?
a. Increases
b. Decreases
c. Does not change
Activation of the Golgi tendon organ of a given muscle:
a. Monosynaptically produces EPSPs on the α motor neuron that returns to that muscle.
b. Is most effectively produced by lengthening of the extrafusal
fibers of that muscle.
c. Polysynaptically produces IPSPs on the α motor neuron that returns to that muscle.
d. Polysynaptically produces EPSPs on the α motor neuron that returns to that muscle.
e. Activates motor neurons that return to the Golgi tendon organ itself
Activation of the Golgi tendon organ of a given muscle:
a. Monosynaptically produces EPSPs on the α motor neuron that returns to that muscle.
b. Is most effectively produced by lengthening of the extrafusal
fibers of that muscle.
c. Polysynaptically produces IPSPs on the α motor neuron that returns to that muscle.
d. Polysynaptically produces EPSPs on the α motor neuron that returns to that muscle.
e. Activates motor neurons that return to the Golgi tendon organ itself
Which of the following is not characteristic of the muscle spindle?
a. Encapsulated intrafusal fibers
b. Sensitivity to muscle tension
c. Sensitivity to dynamic stretching of the muscle
d. Lying parallel to the extrafusal muscle fibers
e. Sensitivity to steady-state length of the muscle
Which of the following is not characteristic of the muscle spindle?
a. Encapsulated intrafusal fibers
b. Sensitivity to muscle tension
c. Sensitivity to dynamic stretching of the muscle
d. Lying parallel to the extrafusal muscle fibers
e. Sensitivity to steady-state length of the muscle
Gamma (γ) motor neurons:
a. Innervate and produce contraction of the equatorial
(middle) region of an intrafusal fiber.
b. Have their cell bodies in the dorsal horn of the spinal cord.
c. Are never activated at the same time as α motor neurons.
d. Can regulate the sensitivity of the muscle spindle sensory organ.
e. Innervate and regulate the sensitivity of the Golgi tendon
organ.
D
Chapter 9
Which of the following would not be considered an upper motor neuron?
a. Bulbospinal motor neurons
b. Corticospinal motor neurons
c. Ventral horn α motor neurons of the spinal cord
d. Corticobulbar motor neurons
C
You examine a dog that is unable to stand and bear weight on the right rear leg. The right rear leg is much smaller in diameter
than the left rear leg. Pinching the toe on the left rear leg results in withdrawal of the left rear leg, but pinching the toe on the right rear leg results in no movement of the right rear leg. The proprioceptive placing response in the left rear leg is normal, but in the right rear leg it is absent. Where is this dog’s pathological lesion?
a. Lower motor neuron to the right rear leg
b. Lower motor neuron to the left rear leg
c. Upper motor neuron controlling the right rear leg
d. Upper motor neuron controlling the left rear leg
e. Neuromuscular synapse of the left rear leg
A
