Deck 2: Physical and Electrical Properties of Cells in the Nervous System

Question 1

Which one of the following is not one of the primary components of a neuron?

A)Axon
B)Soma
C)Postsynaptic membrane
D)Dendrite

Answer 1

C
Explanation: The primary components of a neuron consist of dendrites,which transmit information toward the cell body;the soma or cell body,which synthesizes neurotransmitters;axons,which transmit information away from the cell body to a target cell;and presynaptic terminals,which release neurotransmitters into the synaptic cleft.

Question 2

Multiple sclerosis:

A)Results from an autoimmune attack on oligodendrocytes.
B)Involves demyelination of axons in the CNS.
C)Has signs and symptoms associated with both motor and sensory impairment.
D)Both A and B
E)A,B,and C

Answer 2

E
Explanation: Both Guillain-Barré syndrome (acute idiopathic polyneuritis)and multiple sclerosis are autoimmune disorders that cause demyelination.In multiple sclerosis,demyelination in the CNS produces plaque in the white matter.Because multiple sclerosis attacks the CNS,a greater variety of symptoms occur,including weakness,lack of coordination,visual problems,impaired sensation,slurred speech,memory problems,and abnormal emotional affect.

Question 3

Afferent neurons convey information:

A)Between interneurons.
B)From the CNS to skeletal muscles.
C)From peripheral receptors to the CNS.
D)Between the soma and presynaptic terminal.
E)From the CNS to smooth muscles.

Answer 3

C
Explanation: Afferent neurons carry sensory information from the outer body toward the CNS.Efferent neurons relay commands from the CNS to smooth and striated muscles and glands.Interneurons,the largest class of neurons,act throughout the nervous system,processing information locally or conveying information across short distances.

Question 4

Local potentials:

A)Are either receptor or synaptic potentials.
B)Spread passively only a short distance along the cell membrane.
C)Result from stimulation of sensory receptors or from the binding of a neurotransmitter with chemical receptor sites on a postsynaptic membrane.
D)Both A and B
E)A,B,and C

Question 5

The strength of local electrical potentials is modulated and integrated via:

A)Spatial summation,the combined effect of potentials generated in other parts of the neuron.
B)Temporal summation,the combined effect of small potential changes occurring over several milliseconds.
C)Both A and B
D)None of the above.A local potential is an all-or-none phenomenon.

Question 6

Which of the following is the structural part of a neuron that releases a neurotransmitter?

A)Dendrite
B)Axon hillock
C)Soma
D)Presynaptic terminal
E)Postsynaptic terminal

Question 7

Propagation of an action potential along an axon is dependent on a(n):

A)Complete myelination of the axon by glial cells.
B)Anterograde diffusion of the electric potential with active generation of new potentials.
C)Rapid repolarization associated with passive diffusion of Cl-.
D)Retrograde diffusion of the electrical potential.
E)Na⁺/K⁺ pump moving sufficient quantities of Na⁺ into of the cell and K⁺ out of the cell.

Question 8

Which one of the following neuron structures is specialized for receiving synaptic input from other neurons?

A)Cell body
B)Dendrite
C)Axon
D)Axon hillock
E)Presynaptic terminal

Question 9

The resting membrane potential is:

A)The same as the membrane equilibrium potential.
B)The voltage difference across a neuron's cell membrane,maintained by an unequal distribution of one specific ion.
C)Maintained by active transport of sodium ions (Na⁺)and potassium ions (K⁺)and passive diffusion of Na⁺,K⁺,and chloride ions (Cl-)through the cell membrane.
D)Typically measured at +70 millivolts (mV)because the intracellular environment is more positively charged than the extracellular environment.
E)Created by a more negative charge inside the membrane than outside because Na⁺ is continuously moved inside the cell membrane by an active transport pump.

Question 10

Depolarization occurs when:

A)The membrane potential becomes less negative than the resting membrane potential.
B)The membrane potential becomes more negative than the resting membrane potential.
C)Cl- influx hyperpolarizes the membrane.
D)The presynaptic terminal of a neuron is inhibited by another neuron.
E)All membrane channels are closed,preventing the influx of Na⁺.

Question 11

Which one of the following is an example of divergence?

A)Signals in the neural pathway that leads to contraction of the hip flexor muscles when a painful stimulus is applied to the toe
B)Integration of taste and smell information in the temporal lobe
C)Multiple different cells synapsing with a single neuron in the spinal cord
D)All of the above

Question 12

Guillain-Barré syndrome:

A)Involves demyelination of peripheral axons.
B)Results from an autoimmune attack on Schwann cells.
C)May affect cranial nerves controlling the muscles involved in swallowing,breathing,and facial expression.
D)Both A and B
E)A,B,and C

Question 13

The nodes of Ranvier:

A)Are distributed approximately every 1 to 2 millimeters (mm)along the membrane of the cell axon.
B)Contain a high density of modality-gated K⁺ channels for rapid depolarization of the membrane.
C)Contain a high density of voltage-gated Na⁺ channels for rapid repolarization of the membrane.
D)Have low membrane capacitance,preventing the accumulation of electrical charge.
E)Are heavily myelinated,which allows for rapid diffusion of an electrical potential.

Question 14

Glial cells contribute which of the following?

A)Communication between neurons and blood vessels
B)Neural cell death
C)Action potential propagation
D)Both A and B
E)All of the above

Question 15

Pseudounipolar cells:

A)Have two dendrites
B)Have two somas
C)Are not neurons
D)Are glial cells
E)Have two axon extensions

Question 16

Retrograde transport:

A)Recycles substances from the axon back to the soma.
B)Moves neurotransmitters from the dendrites to the cell body.
C)Moves substances from the soma toward the axon terminal.
D)Moves neurotransmitters across the synaptic cleft.
E)Moves information from astrocyte to astrocyte.

Question 17

Which of the following change the electrical potential across the cell membrane?

A)Activation and opening of ligand-gated K⁺ channels.
B)Activation and opening of modality-gated Na⁺ channels.
C)Activation and opening of voltage-gated Cl- channels.
D)Leak channels,which allow continuous diffusion of small ions.
E)All of the above

Question 18

Demyelination of an axon:

A)Results in decreased membrane resistance,allowing a leakage of electrical current.
B)Results in slowed propagation of action potentials.
C)May prevent propagation of action potentials.
D)Both A and B
E)A,B,and C

Question 19

Peripheral demyelination:

A)Typically affects small diameter axons before large diameter axons.
B)Is a characteristic feature of multiple sclerosis.
C)Affects the structure of oligodendrocytes.
D)Typically affects the Schwann cells of large,well-myelinated axons.
E)Typically affects the axon at the ventral root of the spinal cord.