Neurophysiology Exam 1

The concentration of J+ is 40mM inside the neuron and 5mM outside the neuron. The membrane voltage is +10mV. What will happen to the membrane potential? A. Increase B. Decrease C. No change D. Cannot be determined from the information given

Decrease

Which describes the effect of depolarization on voltage-gated Na and K channels? A. Depolarization opens Na channels and closes K channels B. Depolarization opens Na channels quickly and K channels more slowly C. Depolarization opens Na channels and K channels at the same speed D. Depolarization closes Na channels and opens K channels

Depolarization opens Na channels quickly and K channels more slowly

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Bidirectional

E

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Cytoplasmic continuity between cells

E

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Uses gap-junction channels

E

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Virtually no delay

E

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Depends on relative cell size

E

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Subthreshold presynaptic signals transmitted

E

Which technique(s) can measure the activity of an individual neuron? A) EEG B) Calcium imaging of neural activity C) Intracellular electrophysiology D) Extracellular electrophysiology E) B-D

E) B-D Calcium imaging of neural activity Intracellular electrophysiology Extracellular electrophysiology

What technique was used in the above images? A. Confocal microscopy B. 2-photon fluorescence C. Electron microscopy D. Calcium imaging E. Immunohistochemistry

Electron microscopy

True/False: Ionotropic receptors are always excitatory

F

True/False: Ionotropic receptors can open or close channels

F

True/False: Metabotropic receptors are always inhibitory

F

True/False: Metabotropic receptors are ion channels

F

True/False: Metabotropic receptors only open channels

F

What are electrical synapses often used for? A. Fast, synchronous activation of multiple neurons B. Integration of many inputs C. Sensory transduction D. Local inhibition

Fast, synchronous activation of multiple neurons

What is the primary function of microglia? A. myelinate neurons in CNS B. myelinate neurons in PNS C. regulate contents of extracellular space D. immune response

Immune response

Which statement about the ionic permeability of cell membranes is true? a. In resting nerve cells, the membrane is permeable to all ions. b. The permeability of ions is constant over time. c. In resting nerve cells, the membrane is quite permeable to potassium. d. In resting nerve cells, the membrane is quite permeable to sodium. e. In resting nerve cells, the membrane is quite permeable to calcium.

In resting nerve cells, the membrane is quite permeable to potassium.

Which technique could be used to determine which cells express gene X, if you do NOT have an antibody for the protein it produces? A) DNA sequencing B) In situ hybridization C) immunohistochemistry D) microarray E) B-D

In situ hybridization

What causes the absolute refractory period? A. Inactivation of Na channels B. Opening of Na channels C. Flow of Cl- D. Continued flow of K

Inactivation of Na channels

What causes the unidirectional travel of the action potential? A. Closing of Na channels B. Inactivation of Na channels C. Unidirectional diffusion of ions D. Myelination

Inactivation of Na channels

What would be the effect of making voltage-gated K channels take longer to close? A. Lower the threshold for generating an action potential B. Increase the length of the hyperpolarization phase C. Increase conduction velocity D. Reduce the peak depolarization E. Lower the resting potential

Increase the length of the hyperpolarization phase

Which is true for intracellular vs. extracellular recordings of an action potential? A. Extracellular recordings cannot identify individual action potentials B. Extracellular recordings will show larger voltage changes than intracellular C. Initial voltage change will be positive for intracellular and negative for extracellular recordings D. Intracellular recordings are easier to perform in awake animals E. Intracellular recordings can only be performed in slice preparations

Initial voltage change will be positive for intracellular and negative for extracellular recordings

Which describes optogenetics? A) Ion channels opened or closed by light B) Fluorescent labelling of DNA to look for mutations C) Fluorescent labelling of mRNA to look at gene expression D) Visible phenotypes for mapping mutations

Ion channels opened or closed by light

Which statement about electrochemical equilibrium is true? a. It involves the movement of a relatively large number of ions, altering the concentrations of permeant ions. b. It occurs when the potential across the membrane exactly offsets the concentration gradient. c. The size of the potential is inversely proportional to the size of the ion gradient. d. The fluxes of ion that are required to generate the membrane potential disrupt chemical electroneutrality. e. For a given ion concentration gradient, the resulting potential is independent of the number of charges on the ion.

It occurs when the potential across the membrane exactly offsets the concentration gradient.

In a two-compartment model of a cell with a K+-permeable membrane and a 10-fold excess of K+ in the inside compartment, how would the membrane potential change if all K+ ions were replaced by Na+ ions? a. It would double. b. It would be reduced by half. c. It would not change. d. It would become positive. e. No potential would be generated. (accepted two answers since it was unclear whether K had reached equilibrium before the swap)

It would not change. No potential would be generated.

Concentrations of which ion, inside and outside of a neuron, have the greatest effect on the resting membrane potential? a. K+ b. Na+ c. Ca2+ d. Cl- e. PO43-

K+

Which technique(s) compare gene expression across the entire genome? A) DNA sequencing B) Microarray C) In situ hybridization D) Immunohistochemistry E) B, C, & D

Microarray

What causes the repolarization phase of the action potential? A. Movement of Na into the cell B. Movement of K into the cell C. Movement of Na out of the cell D. Movement of K out of the cell

Movement of K out of the cell

What causes the depolarization phase of the action potential? A. Movement of Na into the cell B. Movement of K into the cell C. Movement of Na out of the cell D. Movement of K out of the cell

Movement of Na into the cell

What is the primary function of oligodendrocytes? A. myelinate neurons in CNS B. myelinate neurons in PNS C. regulate contents of extracellular space D. immune response

Myelinate neurons in CNS

What is the primary function of Schwann cells? A. myelinate neurons in CNS B. myelinate neurons in PNS C. regulate contents of extracellular space D. immune response

Myelinate neurons in PNS

Which will increase action potential conduction velocity? A. Adding more leakage channels B. Reducing axon diameter C. Myelination D. Lowering the threshold

Myelination

Which ion drives excitatory postsynaptic potentials? A. Na+ B. K+ C. Cl- D. Ca2+

Na+

A friend has taken a job in a neuroscience research lab, and is studying neurons in a freshwater snail. He has been told to calculate the equilibrium potential of K+. Which equation will he use and what other information will he need? a. Nernst equation; concentration of K+ inside and outside of the cell b. Nernst equation; concentration of K+ inside and outside of the cell and permeability of K+ c. Goldman equation; concentration of K+ inside and outside of the cell d. Goldman equation; concentration of K+ inside and outside of the cell and permeability of K+ e. Nernst equation; concentration of K+, Na+, and Cl- inside and outside of the cell

Nernst equation; concentration of K+ inside and outside of the cell

Which of these statements is true and important for the effects of electrical stimulation? A) Only dendrites will be excited by electrical current B) Neurons with similar response properties are often located near one another C) Thalamic input synapses mainly into layer IV D) Most synapses are chemical rather than electrical

Neurons with similar response properties are often located near one another

In a two-compartment model of a cell with a K+-permeable membrane, at K+ equilibrium potential, there is _______ flux of K+ ions. a. a large inward b. a large outward c. no net d. a small inward e. a small outward

No net

Which of these techniques can be (legally) used in the brains of living human volunteers? A) Anterograde and retrograde tracers B) In situ hybridization C) Immunohistochemistry D) Optogenetics E) None of the above

None of the above

What is the major determinant of the permeability of a membrane to a specific ion? a. Size of the ion b. Concentration of the ion inside the cell c. Concentration of the ion outside the cell d. Electrical charge of the ion e. Number of open ion channels specific for that ion

Number of open ion channels specific for that ion

What causes the hyperpolarization phase of the action potential? A. Closing of K channels B. Opening of Na channels C. Flow of Cl- D. Open K channels

Open K channels

The concentration of J+ is 40mM inside the neuron and 5mM outside the neuron. The membrane voltage is +10mV. If the membrane suddenly becomes permeable to J, which direction will J flow? A. Inward B. Outward C. No net flow D. Cannot be determined from the information given

Outward

The concentration of J+ is 40mM inside the neuron and 5mM outside the neuron. The membrane voltage is +10mV. What is the direction of the chemical force on J+? A. Inward B. Outward C. 0 D. Cannot be determined from the information given

Outward

The concentration of J+ is 40mM inside the neuron and 5mM outside the neuron. The membrane voltage is +10mV. (Q's 31-35) 31. What is the direction of the electrical force on J+? A. Inward B. Outward C. 0 D. Cannot be determined from the information given

Outward

What is one function of astrocytes? A. myelinate neurons in CNS B. myelinate neurons in PNS C. regulate contents of extracellular space D. immune response

Regulate contents of extracellular space

Which of the images above shows an electrical synapse? A. Left B. Right

Right

Which describes ion CHANNELS? A. selective for specific ion(s) B. unidirectional C. uses ATP D. permeability cannot change E. all of the above

Selective for specific ion(s)

What is the approximate range of conduction velocities of an action potential? A. 1 μm/s unmyelinated - 1 mm/s myelinated B. 1 mm/s unmyelinated - .1 m/s myelinated C. 1 m/s unmyelinated - 100 m/s myelinated D. 10 m/s unmyelinated - 1000 m/s myelinated

1 m/s unmyelinated - 100 m/s myelinate

The IV curves for channels A and B are shown above. Which channel is voltage-gated? A. A B. B C. Both D. Neither

A

How are neurotransmitters removed from the synaptic cleft? A. Diffusion B. Reuptake by presynaptic neuron C. Reuptake by glial cells D. Enzymatic degradation E. All of the above

All of the above

Which describes ion PUMPS? A. uses ATP B. unidirectional C. can move ions against electrochemical driving force D. selective for specific ion(s) E. all of the above

All of the above

Which techniques can be used to eliminate or reduce neural activity? A) Lesions B) Cooling C) Pharmacology D) Optogenetics E) All of the above

All of the above

Which describes Golgi staining? A. Stains all neurons B. Allows you to visualize the axon and dendrites C. Is selective for excitatory neurons D. Stains only nuclei & nearby material

Allows you to visualize the axon and dendrites

The amplitude of the action potential of a given neuron is a. larger in response to depolarizing currents of greater magnitude. b. dependent on the magnitude of the sensory stimulus. c. related to the number of synapses on the neuron. d. smaller if the resting potential of the neuron is lower. e. always the same.

Always the same

Which factor is important in determining the membrane potential when there are multiple permeant ions? a. The concentration gradient of the individual ionic species b. The permeability of the membrane to the individual ionic species c. The sum total of all of the ions on both sides of the membrane d. Both a and b e. All of the above

Both a and b The concentration gradient of the individual ionic species and the permeability of the membrane to the individual ionic species

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. All or none

C

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Larger distance between cell membranes

C

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Unidirectional

C

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Uses vesicles

C

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Variable delay

C

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Can amplify signal

C

Label each of the following as a characteristic of electrical (E) or chemical (C) synapses. Uses receptors

C

Which ion triggers vesicle fusion at the synapse? A. Na+ B. K+ C. Cl- D. Ca2+ E. None of the above

Ca2+

Which ion drives inhibitory postsynaptic potentials? A. Na+ B. K+ C. Cl- D. Ca2+

Cl-

Which statement about ionic distributions in nerve cells is true? a. Potassium is higher outside cells than inside cells. b. Sodium is higher outside cells than inside cells. c. Chloride is higher inside cells than outside cells. d. Calcium is higher inside cells than outside cells. e. The concentrations of all ionic species are the same for all nerve cells in all animals.

Sodium is higher outside cells than inside cells

Which describes Nissl staining? A. Stains only a small fraction of neurons B. Allows you to visualize the axon and dendrites C. Is selective for excitatory neurons D. Stains only nuclei & nearby material

Stains only nuclei & nearby material

True/False: Both ionotropic and metabotropic receptors are transmembrane proteins

T

True/False: Ionotropic receptors exert their effects more quickly than metabotropic receptors

T

True/False: Metabotropic receptors use second-messenger systems to exert their effects

T

True/False: The same neuron can express both ionotropic and metabotropic receptors

T

True/False: The same neurotransmitter can bind both ionotropic and metabotropic receptors

T

The concentration of J+ is 40mM inside the neuron and 5mM outside the neuron. The membrane voltage is +10mV. If the membrane remains permeable only to J, what will the membrane voltage eventually be? A. Positive B. Negative C. the equilibrium potential of J D. 0

The equilibrium potential of J

Hodgkin and Katz proposed that sodium was the predominant ion associated with the firing of an action potential because a. the membrane potential approaches the Na+ Nernst potential during the rising phase. b. the membrane potential approaches the Na+ Nernst potential during the falling phase. c. sodium ions can move more quickly than other ionic species. d. sodium ions are the only ions that can flow into the nerve cell body. e. the sodium gradient explains the rising phase, falling phase, and undershoot of the action potential.

The membrane potential approaches the Na+ Nernst potential during the rising phase

In a two-compartment model of a cell with a K+-permeable membrane and a 10-fold excess K+ in the inside compartment, the membrane potential is experimentally made more negative than the K+ equilibrium potential. How would K+ ions flow across the membrane? a. They would flow from the inside compartment to the outside compartment. b. They would flow from the outside compartment to the inside compartment. c. There would be no flow of K+ ions. d. They would flow in both directions at the same time in equal molar quantities. e. They would flow in both directions, but the flow would be negligible.

They would flow from the outside compartment to the inside compartment.

Which of the following is NOT a characteristic of the action potential? A. All or none B. Followed by a refractory period C. Variable amplitude D. Travels in one direction

Variable amplitude

What is the difference between transgenic and viral methods for DNA manipulation? A) Viral methods alter DNA in every cell in the animal B) Only transgenic methods can express novel genes C) Only transgenic methods can target a subset of neurons D) Only viral methods can target a subset of neurons E) Viral effects are spatially restricted

Viral effects are spatially restricted

Under which circumstances is the Goldman equation (to calculate equilibrium potential for a cell) equivalent to the Nernst equation (which calculates equilibrium potential for one ion)? a. When a membrane is permeable to only one ion b. When a membrane is permeable to multiple ions c. When the membrane is permeable to positively charged ions only d. When the membrane is permeable to negatively charged ions only e. When permeability of the membrane is different for different ions

When a membrane is permeable to only one ion

Which is a major source of information about the connections between brain areas? A) Anterograde and retrograde tracers B) Nissl staining C) Golgi staining D) fMRI E) Dissections

Anterograde and retrograde tracers

The resting potential of a cell is negative because a. there is an excess of K+ outside of the cell at rest. b. at rest there is an excess of K+ outside of the cell, and the membrane is permeable chiefly to K+. c. at rest there is an excess of K+ inside the cell, and the membrane is permeable chiefly to K+. d. at rest there is an excess of K+ inside the cell, but the membrane is permeable to all ions. e. there is an excess of Cl- ions outside of the cell at rest.

At rest there is an excess of K+ inside the cell, and the membrane is permeable chiefly to K

Where on a myelinated axon does active propagation occur? A. At the Nodes of Ranvier B. In between the Nodes of Ranvier C. Along the entire axon D. Nowhere, active propagation occurs only in unmyelinated axons E. Nowhere, active propagation occurs only in dendrites

At the Nodes of Ranvier

In the patch clamp recording above, which period of the recording shows the channel in an OPEN state? A. A B. B C. Both D. Neither

B

How does the resting membrane potential of a typical neuron compare to the equilibrium potential (calculated by the Nernst equation) for potassium? a. The resting membrane potential is not exactly equal to the equilibrium potential for potassium because of variation among neurons. b. The resting membrane potential is not exactly equal to the equilibrium potential for potassium because rapid fluctuations in membrane potential prevent accurate measurements. c. The resting membrane potential is not exactly equal to the equilibrium potential for potassium because the membrane has some resting permeability to species other than potassium. d. The resting membrane potential is not exactly equal to the equilibrium potential for potassium because potassium does not contribute to the resting membrane potential. e. The resting membrane potential is exactly equal to the equilibrium potential for potassium.

The resting membrane potential is not exactly equal to the equilibrium potential for potassium because the membrane has some resting permeability to species other than potassium

Which describes immunohistochemistry? A) The use of antibodies to label proteins in tissue B) Manipulating the genome to create fluorescent fusion proteins C) Using viral vectors to express fluorescent fusion proteins D) Proteins must be separated from cells before they can be measured

The use of antibodies to label proteins in tissue