Neurophysiology Answers to End-of-

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Logothetis: Local Anesthesia for the

Dental Hygienist Chapter 02:

Neurophysiology Answers to End-of- chapter Review Questions and Answers Already Passed

What is the role of sodium ions during nerve impulse conduction?

• They block the nerve impulse
• They maintain the resting potential

✔✔ C. They rush into the neuron to depolarize it

• They exit the cell during depolarization

What happens when a local anesthetic is applied to a nerve?

• It opens sodium channels permanently
• It stimulates the nerve

✔✔ C. It blocks sodium ion influx

• It speeds up the nerve conduction

Which of the following best describes a resting nerve fiber? 1 / 4

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• It is depolarized
• It is flooded with sodium ions inside

✔✔ C. It has a negative charge inside

• It has an action potential

What is the threshold potential in a neuron?

• The most negative potential possible

✔✔ B. The minimum level required to trigger an action potential

• The charge required to open potassium channels
• The potential after repolarization

Which ion is primarily responsible for repolarization of the nerve?✔✔ A. Potassium

• Sodium
• Calcium
• Chloride

Which of the following statements is true about local anesthetics and nerve conduction? 2 / 4

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• They stimulate potassium release

✔✔ B. They prevent depolarization by blocking sodium entry

• They permanently alter nerve structure
• They open calcium channels

Myelinated nerves conduct impulses more rapidly because:

• They are shorter in length
• They contain more sodium

✔✔ C. They use saltatory conduction between nodes

• They require less energy

The all-or-none principle means:

✔✔ A. A nerve fires completely or not at all

• A nerve only fires if a stimulus is weak
• A stronger stimulus causes a larger action potential
• The nerve will fire repeatedly with a weak signal

Where do local anesthetics primarily act on the neuron? 3 / 4

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• The axon hillock
• The synaptic vesicle

✔✔ C. The nerve membrane (axon membrane)

• The dendrite

Which of the following is NOT needed for a nerve impulse to occur?

• Sodium influx

✔✔ B. Permanent membrane blockage

• Threshold stimulus
• Membrane depolarization

Which statement about action potentials is correct?

• They vary in strength depending on the stimulus

✔✔ B. They have the same size once threshold is reached

• They increase with repeated stimuli
• They occur without ion movement

What effect does local anesthesia have on nerve repolarization?

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