Cell Neuro - Exam 1 Practice Questions - Nelson

C

How can a neuron who's resting membrane potential is -56mV alter its membrane potential? (A) Open voltage gated potassium channels (B)Open voltage gated sodium channels (C)A and B

E

In which part of a neuron would the endoplasmic reticulum be concentrated? A) Dendrite B) Axon C) Postsynaptic terminal D) Presynaptic terminal E)Cell Body

E

Myelin.... (A)Increases capacitance (B)Increases resistance (C)Speeds up conduction velocity (D)A and C (E)B and C

C

Nerve cells are most permeable to...(A)Sodium (B)Calcium (C)Potassium (D)Chloride (E)Potassium and Chloride equally

E

A surprising result that emerged from the molecular and genetic analysis of ion channels was the a) size of the individual ion channels. b) voltage-dependence of the ion channels. c) time-dependence of the ion channels. d) discovery of differences in ionic selectivity. e) sheer number of different ion channels.

A

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-

D

A neuron has received enough stimulation to fire an action potential. It has also been treated with TEA, a K+ channel blocker. Which outcome is possible? A) The cell will initially hyperpolarize and will return to resting membrane potential after a delay B) There will be no change in the membrane potential in the cell C) The cell will initially depolarize and will continue to do so until the cell reaches the equilibrium potential for Na+ D) The cell will initially depolarize, but repolarization will take much longer because it relies only on ion pumps E) There will be no change in membrane potential in the cell initially, but it will depolarize after a delay

D

From which part of the nervous system do cells that innervate neuromuscular junctions originate? A) Peripheral nervous system (PNS) B) Autonomic nervous system C) Somatic motor division of the PNS D) Central nervous system (CNS) E) Visceral motor division of the PNS

A

Subthreshold current injectied into an axon flows ________ along the axon and ______ with distance from the site of injection. A) Passively ; decays B) Actively ; decays C) Actively ; grows D) Actively ; remains constant E) Passively ; remains constant

True

The brain has both gray and white matter. True or false?

A

The part of a synapse to which the contents of synaptic vesicles bind is called the A) receptor B) presynaptic terminal C) terminal bouton D) axon terminal E) synaptic ending

C

What is the primary pathophysiological mechanism associated with multiple sclerosis? A) Loss of trophic support of the axon B) Myelin loss C) Immune response within the nervous system D) Immune cell infiltration E) Axon damage

D

Which of the anatomical lobes just described primarily deals with vision and visual processing? (A)Frontal (B)Parietal (C)Temporal (D)Occipital

D

Which of the following is/are true regarding the graphs on the right? (A)This is a voltage clamp experiment (B)Stepping to -26 mV results in no outward current (C)Stepping to 0mV results in current with greater magnitude than stepping to -26mV (D)A and C (E)A, B and C

D

Which treatment was shown to eliminate the early inward current in squid giant axons? A) Doubling of external sodium B) Removal of external potassium C) Removal of all external cations D) Removal of external sodium E) Doubling of external potassium

B

An action potential is a(n) ____ change in the electrical potentail across the nerve cell membrane. A) permanent B) all or nothing C) single D) random E) unidirectional

A

An action potential occurs if current injected into a neuron _______ the neuron to reach ________ potential. A) depolarizes ; threshold B) hyperpolarizes ; synaptic C) hyperpolarizes ; resting D) depolarizes ; synaptic E) hyperpolarizes ; threshold

D

If the goal of anesthetics is to reduce sensation by interfering with electrical signals, which of these are a reasonable mechanism for how anesthesia might work? (A)Blocking action potential propagation (B)Enhancing inhibition (C)Enhancing excitation (D)A and B (E)A, B and C

A

If we were to compare the magnitude of the Na+ current when the Vmis held at 0 vs +40mV, which would have larger sodium current? (A)0 mV (B)+40 mV

B

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 small outward B) no net C) a small inward D) a large inward E) a large outward

E

In the mature central nervous system, glial stem cells with the properties of astrocytes can give rise to... A) Astrocytes B) Neurons C) Oligodendrocytes D) Astroctyes and oligodendrocytes E) Astrocytes, oligodendrocytes, and neurons

C

In which of the spinal cord regions just described is an epidural administered? (A)Cervical (B)Thoracic (C)Lumbar (D)Sacral

B

K+ ions can travel through Na+channels but Na+ions cannot travel through K+channels. (A)True (B)False

D

Neurons and Glial cells differ in the distribution of the organelles within each type of cell. Which of the following statements about this distribution is true? (A)Mitochondria would be near the nucleus in both neurons and glial cells (B)The neuron would probably not have protein-making machinery in its dendrites (C)The neuron would have mitochondria near the synapses (D)A and B (E)B and C

C

Ouabain is a compound that inhibits the sodium potassium pump (Na+K+ATPase). What would be the immediateeffect of inhibiting the pump on the membrane potential of a neuron? a.No change b.Slight hyperpolarization c.Slight depolarization d.Membrane potential would become zero

D

Ouabainis a compound that inhibits the sodium potassium pump (Na+K+ATPase). What would be the long term effect of inhibiting the pump on the membrane potential of a neuron? a.No change b.Slight hyperpolarization c.Slight depolarization d.Membrane potential would become zero

D

Practically speaking, how would you determine that Na+ influx into a cell underlies the early current? A) Treat the cell with tetraethylammonium B) Use the voltage clamp method to measure the current C) Remove K+ from the intracellular compartment and assess the early current under the new conditions D) Remove Na+ from the extracellular compartment and assess the current under new conditions E) Replace intracellular Na+ with its radioactive form and trace its movement across the membrane

A

Using the Eion that you calculated in the previous question (-61 mV), answer this question: At -20mV, chloride would move ________ and at -90mV, chloride would move __________. (A)Into the cell ; out of the cell (B)Out of the cell ; into the cell

B

When current is injected into an axon, A) an action potential is evoked before the current has spread any distance from the point of injection B) the current will decay exponentially with increasing distance from the injection site (if no action potential is present) C) the current will spread passively only if it is a depolarizing current D) the current will spread in only one direction E) the current will propagate as an oscillating wave independently of its polarity

B

Which cell produces myelin in the nerves of the peripheral nervous system? A) Astrocyte B) Schwann Cell C) Neural progenitor cell D) Microglia E) Neuron

D

Which component represents the peripheral nervous system? A) Nucleus (i.e. group of neurons) B) Column C) Commissure D) Spinal nerve E) Tract

D

Which consequence of Na+ channels staying open, instead of closing after membrane depolarization, is most plausible? A) The refractory period would be longer B) The refractory period would be shorter C) Action potentials would spread both ways, forward and backward D) The membrane would not repolarize (return to a negative value of membrane potential) following depolarization E) None of the above

C

Which function is a characteristic primarily of neurons only and not glia? A) Supports electrical signals B) Prevents regeneration of the nervous system C) Transmits action potentials D) Repairs the nervous system E) Produces myelin

C

Which glial cell type serves as a resident immune cell in the central nervous system? (A)Astrocyte (B)Glial stem cell (C)Microglia (D)Schwann Cell (E)Oligodendrocyte

E

Which ion has a strong driving force (chemical gradient) to come into a nerve cell? (A)Na (B)K (C)Cl (D)Ca (E)More than one of these

C

Which of the following describes why the inside of the cell is negative relative to the outside? (A)Because Na+ concentration is high outside cells (B)Because K+ concentration is high inside cells (C)Because K+ leak channels allow K+ to flow out, down it's concentration gradient (D)B and C (E)A, B and C

E

Which of the following is NOT integral to the action potential waveform? A) A change in the permeability of the membrane to potassium B) A change in permeability of the membrane to sodium C) A transient increase in the sodium current D) A "self activating" aspect to the rise in the sodium current E) An initial decrease in the potassium current

E

Which of the following is not an observation that helped to identify sodium as the early current of the action potential? (A)The current disappeared near the Nernst potential for sodium. (B)The early current was blocked by tetrodotoxin. (C)The early current was unaffected by tetraethylammonium. (D)Removing extracellular sodium eliminated the early current. (E)Blocking the late current caused the inward current to produce a negative membrane potential

E

Which statement about myelination is false? a) Myelin sheaths are created by glial cells. b) Multiple layers of closely opposed glial membranes wrap the axon and serve as an electrical insulator. c) Myelin is absent at the nodes of Ranvier. d) Sodium and potassium channels are clustered at the nodes of Ranvier. e) None of the above

B

Which statement best describes the Nernst equation? A) It relates the equilibrium potential of an ion to its intracellular concentration B) It relates the equilibrium potential of an ion to its intra and extracellular concentrations C) It relates the equilibrium potentials of multiple ions to their intracellular concentrations D) It relates the equilibrium potential of an ion to its extracellular concentration E) It relates the equilibrium potentials of multiple ions to their intra and extracellular concentrations

E

Which statement best describes the function of a neuron with multiple, highly branched dendrites and one axon? A) The information it receives will not be relayed B) It can't integrate information from multiple neurons C) It passes information directly to multiple neurons D) It receives information from only one other neuron E) It integrates information from many neurons

D

Which statement correctly differentiates between the passive and active current in a myelinated axon? A) The passive current flows in one direction along the axon, unlike the active current. B) The action potential propagation depends on the passive current only. C) The passive current flows only in the Nodes of Ranvier, unlike the active current. D) The active current flows on in the Nodes of Ranvier, unlike the passive current. E) The action potential propagation depends on the active current only.

C

Which statement correctly differentiates between the passive and active current in a myelinated axon? A) The passive current flows only in the Nodes of Ranvier, unlike the active current. B) The action potential propagation depends on the active current only. C) The active current flows on in the Nodes of Ranvier, unlike the passive current. D) The action potential propagation depends on the passive current only. E) The passive current flows in one direction along the axon, unlike the active current.

E

Which statement regarding refractory periods is true? a) They allow neurons to fire an unlimited number of action potentials per unit of time. b) During the refractory period the cell requires a less intense stimulus to reach threshold. c) The refractory period arises in part due to the increase in sodium conductance across the membrane. d) The refractory period arises in part due to the decrease in potassium conductance across the membrane. e) The refractory period ends when the sodium channels are no longer inactivated

B

Which statement(s) about Na+ permeability during an action potential is/are most accurate? A) It is long lasting B) It is responsible for the rising phase of the action potential C) It is responsible for the falling phase of the action potential D) It restores the membrane potential to its usual level following the action potential E) All of the above

E

Which type(s) of electrical signal(s) occur(s) within the neural circuit for a spinal reflex? A) Receptor potential only B) Action potential only C) Synaptic potential only D) Receptor potential and synaptic potential only E) Receptor potential, synaptic potential, and action potential

B

Why is it correct to say that nerve cells at rest are permeableto potassium? (A)Because K+ flows out when voltage gated channels open (B)Because there are K+ leak channels that allow passive K+ ion flow (C)Because K+ helps with the repolarizing phase of the action potential

B

Why is the white matter lighter than the gray matter? A) These are just historic terms, not representative of real colors B) White matter is richer in myelin, which reflects more light than gray matter C) White matter contains more Schwann cells, which are light in appearance D) White matter is less dense than gray matter E) White matter is more translucent than gray matter

B

Why is there a little blip in the current trace when the cell is clamped at +65mV? (A)Because the K+current at that high of a voltage has to activate twice (B)Because you are clamping above Na+ equilibrium potential and seeing an outward Na+ current (C)Because Na+channels get blocked at that high of a voltage

Cell has increased permeability to Na+

You have discovered a cell with a positive resting membrane potential. Assuming that the cells have normal ion concentrations inside and outside the cell, what would explain the positive resting membrane potential?

A

You have discovered an unknown cell but you know that it came from the nervous system. Which of the features below would indicate to you that this is a neuron? (A)Presence of myelin (B)Uniform distribution of mitochondria (C)Starlike appearance (D)Strong connection to a neighboring nervous system cell (E)All of the above

C

The classic voltage clamp technique would be suitable for which application? A) Evaluation of effects of large intracellular molecules on the function of ion channels B) Study of the ionic composition of the intracellular environment C) Direct measurement of current flowing through a cell membrane D) Indirect measurement of unidirectional current flowing through a cell membrane E) Measurement of current flowing through a single ion channel

A

Axons can be unmyelinated and therefore gray matter. (A)True (B)False

D

The resting membrane potential typically ranges from _______ to ________. A) -90 mV ; 90 mV B) 40 mV ; 90 mV C) 40 V ; 90 V D) -40mV ; -90 mV E) 0 mV ; 90 mV

B

The same glial cells synthesize myelin in the central and peripheral nervous systems. (A)True (B)False

True

The spinal cord has both gray and white matter. True or false?

D

The resting potential of a cell is negative because... A) There is an excess of Cl- ions outside of the cell at rest. B) At rest there is an excess of K+ inside the cell, but the membrane is permeable to all ions. C) At rest there is an excess of K+ outside the cell, and the membrane is permeable chiefly to K+. D) At rest there is an excess of K+ inside the cell, and the membrane is permeable chiefly to K+. E) there is an excess of K+ outside the cell at rest.

A

The voltage clamp method controls the ____________ at any desired level. A) membrane potential B) Na+ current C) K+ current D) amplitude of the action potential E) frequency of the action potential

E

There is an excess of __________ in the extracellular compartment, relative to the intracellular compartment A) Na+ only B) K+ only C) Na+ and Ca2+ only D) Na+ and Cl- only E) Na+, Ca2+ and Cl-