Question 1

Prolonged changes in neuronal activity are achieved through the activation of which of the following?&#10;A)Voltage gated chloride channels&#10;B)Transmitter gated sodium channels&#10;C)G-protein coupled channels&#10;D)Voltage gated potassium channels

Accepted Answer

G-protein coupled channels are involved in prolonged changes in neuronal activity through second messenger systems, which can lead to long-term changes in gene expression and synaptic strength. Voltage gated chloride channels, transmitter gated sodium channels, and voltage gated potassium channels are important for neuronal signaling and maintaining resting membrane potential, but are not directly involved in prolonged changes in neuronal activity.

Question 2

Hypoventilation causes arterial blood carbon dioxide levels to rise. Higher arterial blood carbon dioxide levels increase neuronal activity.&#10;A)Both statements are correct&#10;B)Both statements are incorrect&#10;C)The first statement is correct; the second statement is not correct&#10;D)The first statement is not correct; the second statement is correct

Accepted Answer

The first statement is correct as hypoventilation leads to retention of carbon dioxide and consequent rise in arterial blood carbon dioxide levels. The second statement is not correct, as higher arterial blood carbon dioxide levels actually decrease neuronal activity through the mechanism of cerebral vasodilation and neuronal depression.

Question 3

Hypoventilation is most likely to have which of the following effects on a typical neuron in the central nervous system?&#10;A)Decreased neuronal activity&#10;B)Increased neuronal activity&#10;C)Increased synaptic delay&#10;D)Decreased synaptic delay

Accepted Answer

Hypoventilation results in decreased levels of oxygen and increased levels of carbon dioxide in the bloodstream. This can lead to respiratory acidosis, which can depress neuronal activity in the central nervous system.

Question 4

Forced rapid breathing results in alkalization of the blood, which would lead to which of the following changes in neuronal activity?&#10;A)A decrease in neuronal activity&#10;B)An increase in neuronal activity&#10;C)An initial decrease followed by an increase&#10;D)No change in neuronal activity

Accepted Answer

An increase in alkalinity of the blood due to forced rapid breathing would lead to an increase in neuronal activity. This is because increased alkalinity leads to a decrease in carbon dioxide levels, which is a potent vasodilator. Vasodilation leads to an increase in blood flow and oxygenation, which enhances neuronal activity.

Question 5

Which of the following neurotransmitters is thought to be involved in the phenomenon of presynaptic inhibition?&#10;A)GABA&#10;B)Serotonin&#10;C)Norepinephrine&#10;D)Acetylcholine

Accepted Answer

GABA is the neurotransmitter most commonly associated with presynaptic inhibition. It acts on presynaptic receptors to decrease calcium influx and decrease neurotransmitter release from the presynaptic neuron.

Question 6

Transmission of the electrical signal from the dendrites to the soma of a neuron occurs by which of the following?&#10;A)Short circuit current flow&#10;B)An action potential mechanism&#10;C)Electrotonic conduction&#10;D)Capacitive discharge

Accepted Answer

Electrotonic conduction is the process by which electrical signals are passively transmitted across the dendrites and soma of a neuron. This involves the movement of ions through the neuron's membrane, which changes the membrane potential without generating an action potential.

Question 7

Transmitter activation of ion channels on dendrites can dictate neuronal excitation or inhibition acutely by affecting which aspect of the soma membrane?&#10;A)Electrical capacitance&#10;B)Electrical potential&#10;C)Structure&#10;D)Surface area

Accepted Answer

Transmitter activation of ion channels on dendrites can change the electrical potential at the soma membrane, which can lead to neuronal excitation or inhibition.

Question 8

Which of the following statements best describes the role of calcium in the release of a neurotransmitter substance from the presynaptic nerve terminal?&#10;A)Calcium entry into the presynaptic terminal prevents the release of the neurotransmitter&#10;B)Calcium entry into the presynaptic terminal is necessary for the release of the neurotransmitter&#10;C)Calcium induces the opening of calcium-dependent sodium channels on the presynaptic terminal&#10;D)Calcium entry into the presynaptic terminal results in the formation of cyclic adenosine monophosphate, which induces a conformational change in the presynaptic sodium channel that leads to the release of neurotransmitter

Accepted Answer

Calcium entry into the presynaptic terminal is necessary for the release of the neurotransmitter. When an action potential reaches the presynaptic terminal, it depolarizes the membrane, causing voltage-gated calcium channels to open. The entry of calcium ions triggers the fusion of neurotransmitter-containing vesicles with the presynaptic membrane, releasing the neurotransmitter into the synaptic cleft. Therefore, without calcium entry, neurotransmitter release cannot occur.

Question 9

Posttetanic facilitation is thought to be the result of which of the following?&#10;A)Opening voltage-gated sodium channels&#10;B)Opening transmitter-gated potassium channels&#10;C)A buildup of calcium in the presynaptic terminal&#10;D)Electrotonic conduction

Accepted Answer

Posttetanic facilitation is believed to result from a buildup of calcium in the presynaptic terminal. This increased calcium concentration can lead to a greater release of neurotransmitter in response to subsequent action potentials.

Question 10

An excitatory postsynaptic potential is most likely to result from which of the following?&#10;A)Simultaneous opening of sodium and chloride channels&#10;B)Opening of potassium channels&#10;C)Opening of sodium channels&#10;D)Opening of calcium channels

Accepted Answer

An excitatory postsynaptic potential (EPSP) results from the opening of ion channels that allow positive ions such as sodium to enter the cell, depolarizing the membrane potential. The most likely ion channel to produce this effect is the opening of sodium channels (choice C). Choices A, B, and D do not involve the influx of enough positive charge to depolarize the membrane potential and lead to an EPSP.

Question 11

In a neuron with a resting membrane potential of -65 mV, the distribution of which ion across the neuronal membrane represents the greatest potential electromotive force?&#10;A)Potassium&#10;B)Chloride&#10;C)Sodium&#10;D)Calcium

Accepted Answer

The answer of In a neuron with a resting membrane...

Question 12

Increased conductance of which of the following ions is most likely to have the least effect on membrane potential?&#10;A)Chloride&#10;B)Potassium&#10;C)Sodium

Accepted Answer

The answer of Increased conductance of which of the following...

Question 13

In a neuron with a resting membrane potential of -65 mV, the distribution of which ion across the neuronal membrane represents the least potential electromotive force?&#10;A)Potassium&#10;B)Chloride&#10;C)Sodium&#10;D)Calcium

Accepted Answer

The answer of In a neuron with a resting membrane...

Question 14

The opening of which of the following ion channels would have the least effect on the resting membrane potential of an average neuron?&#10;A)Sodium&#10;B)Potassium&#10;C)Chloride

Accepted Answer

The answer of The opening of which of the following...

Question 15

An inhibitory postsynaptic potential is most likely to result from opening which of the following?&#10;A)Potassium channels&#10;B)Sodium channels&#10;C)Voltage-gated sodium channels&#10;D)Voltage-gated calcium channels

Accepted Answer

The answer of An inhibitory postsynaptic potential is most likely...

Deck 46: Organization of the Nervous System, Basic Functions of Synapses, and Neurotransmitters