Question 1

Which part of the neuron is primarily responsible for conducting electrical impulses away from the cell body?

Accepted Answer

Axon

Question 2

What is the typical change in membrane potential during the peak of an action potential in a neuron?

Accepted Answer

$$+30\,mV$$

Question 3

Which of the following best describes the propagation of an action potential along an axon?

Accepted Answer

The pulse is constant in magnitude and duration, independent of stimulus intensity.

Question 4

If a steady voltage $$V_0 is $$applied at one point in the axon membrane, how does the voltage $$V(x)$$ change with distance $$x$$ from the point of application?

Accepted Answer

$$V(x) = V_0$ e$$^{-x/\lambda}$$

Question 5

What is the primary function of sensory neurons?

Accepted Answer

Receive stimuli from sensory organs and convey messages about the environment

Question 6

In the vertebrate nervous system, how is the signal typically transmitted across the synapse?

Accepted Answer

By release and diffusion of a chemical substance

Question 7

A nerve impulse is produced only if the stimulus exceeds a certain threshold value. What is this phenomenon called?

Accepted Answer

All-or-none response

Question 8

Which of the following is true about the duration of action potentials in muscle fibers compared to neurons?

Accepted Answer

Muscle action potentials are usually longer (about 20 msec) than those in neurons.

Question 9

What is the approximate speed at which fast-acting axons can propagate an action potential?

Accepted Answer

$$100\,m/sec$$

Question 10

Which equation describes the exponential decrease of voltage along an axon when a steady voltage is applied?

Accepted Answer

$$V(x) = V_0$ e$$^{-x/\lambda}$$

Question 11

At a distance of $$0.8\,mm$$ from the point of voltage application on the axon, the voltage decreases to what percentage of its original value?

Accepted Answer

37%

Question 12

Which of the following best describes the role of interneurons?

Accepted Answer

Transmit information between neurons

Question 13

What is the typical resting potential of a neuron before an action potential occurs?

Accepted Answer

$$-70\,mV$$

Question 14

Which of the following is NOT a typical stimulus that can elicit a nerve impulse?

Accepted Answer

Light emission from the axon

Question 15

What is the function of dendrites in a neuron?

Accepted Answer

Receive input signals from other neurons

Question 16

During synaptic transmission, what happens when the action potential reaches the nerve ending?

Accepted Answer

A chemical substance is released and diffuses across the synaptic gap

Question 17

Which of the following best explains why the action potential is considered an 'all-or-none' event?

Accepted Answer

It only occurs if the stimulus exceeds a threshold, and is always the same size

Question 18

What is the main difference between the transmission of action potentials in muscle fibers and neurons?

Accepted Answer

Action potentials in muscle fibers have a longer duration

Question 19

Which of the following is a correct statement about the synaptic gap?

Accepted Answer

It is typically about $$1\,mm = 10$$^{-9}$$\,m$$

Question 20

A patient receives a stimulus to a neuron that does not exceed the threshold value. What is the expected response?

Accepted Answer

No action potential is generated

Biophysics: Electrobiology – Nervous System, Action Potentials, and Axon Circuits

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