Chapter 45 Results From The Opening Potassium Channels Results

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Hall: Guyton and Hall Textbook of Medical Physiology, 12th Edition

Chapter 45: Organization of the Nervous System, Basic Functions of Synapses, and

Neurotransmitters

Test Bank

Choose the best answer

1. Prolonged changes in neuronal activity are achieved through the activation of:

A. Voltage gated chloride channels

B. Transmitter gated sodium channels

C. G-protein coupled channels

D. Voltage gated potassium channels

2. 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

(EMF)?

A. Potassium

B. Chloride

C. Sodium

D. Calcium

3. Inhibition of neuronal activity can be achieved by:

A. Allowing calcium to enter the presynaptic membrane

B. Opening sodium channels

C. Opening sodium and chloride channels simultaneously

D. Opening postsynaptic calcium channels

4. Transmission of the electrical signal from the dendrites to the soma of a neuron occurs

by:

A. Short circuit current flow

B. An action potential mechanism

C. Electrotonic conduction

D. Capacitive discharge

5. Post-tetanic facilitation is thought to be the result of:

A. Opening voltage-gated sodium channels

Test Bank

45-2

B. Opening transmitter gated potassium channels

C. A build up of calcium in the presynaptic terminal

D. Electrotonic conduction

6. Hypoventilation has which effect on neuronal activity?

A. Hypoventilation depress neuronal activity

B. Hypoventilation increases neuronal activity

C. Hypoventilation increases synaptic delay

D. Hypoventilation decreases neurotransmitter release

7. The opening of which of the following ion channels would have the least effect on the

resting membrane potential of an average neuron?

A. Sodium

B. Potassium

C. Chloride

D. The opening of any of the above ion channels would effect the resting membrane

potential to a similar degree

8. An excitatory postsynaptic potential (EPSP):

A. Results from the simultaneous opening of sodium and chloride channels

B. Results from the opening of potassium channels

C. Results from the opening of sodium channels

D. Results from the opening of calcium channels

9. An inhibitory postsynaptic potential (IPSP):

A. Results from the opening of potassium channels

B. Results from the opening of sodium channels

C. Results from the opening of voltage-gated sodium channels

D. Results from the opening of voltage-gated calcium channels

10. Which of the following statements best describes the role of calcium in the release of a

neurotransmitter substance from the presynaptic nerve terminal?

A. Calcium entry into the presynaptic terminal prevents the release of the

neurotransmitter

B. Calcium entry into the presynaptic terminal is necessary for the release of the

neurotransmitter

Test Bank

45-3

C. Calcium induces the opening of calcium-dependant sodium channels on the

presynaptic terminal

D. Calcium entry into the presynaptic terminal results in the formation of cAMP which

induces a conformational change in the presynaptic sodium channel that leads to the

release of neurotransmitter

11. Which of the following neurotransmitters is thought to be involved in the phenomenon of

presynaptic inhibition?

A. GABA

B. Serotonin

C. Norepinephrine

D. Acetylcholine

12. Forced rapid breathing results in alkalization of the blood which would lead to which of

the following changes in neuronal activity?

A. A decrease in neuronal activity

B. An increase in neuronal activity

C. An initial decrease followed by an increase

D. No change in neuronal activity

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 (EMF)?

A. Potassium

B. Chloride

C. Sodium

D. Calcium