Deck 16: Neurophysiology of Nerve Impulses: Frog Subjects

Question 1

A compound action potential .

A) may be recorded from a nerve
B) is the sum of action potentials in many axons, is graded, and may be recorded from a nerve
C) is the sum of action potentials in many axons
D) is graded

Answer 1

B

Question 2

The neurotransmitter released from the axon terminal .

A) may excite or inhibit the next cell depending on which receptors for the neurotransmitter are present
B) varies in its effect, depending on the shape of the action potential
C) inhibits the next cell
D) excites the next cell

Answer 2

A

Question 3

A neuron _.

A) is absolutely refractory to stimulation during the time Na+ permeability is changing, and immediately following this change
B) will generate an action potential every time it is stimulated
C) can generate another action potential during the time Na+ permeability is changing and immediately following this change, but only if stimulus strength is increased

Answer 3

A

Question 4

Net movement of this ion is primarily associated with repolarization.

A) Na+
B) Mg2+
C) Ca2+
D) K+

Question 5

The ionic concentrations in the interior and exterior of body cells .

A) reveal an excess of Na+ ions in the extracellular fluid
B) reveal an excess of Na+ ions in the intracellular fluid
C) reveal an excess of K+ ions in the extracellular fluid
D) are the same

Question 6

Neurons and other excitable cells respond to stimuli by producing .

A) electrical signals
B) pressure gradients
C) and secreting chemical messengers

Question 7

Which nerve innervates the gastrocnemius muscle of the frog?

A) fibular
B) plantar
C) sciatic (tibial branch)
D) femoral

Question 8

The effects of electrical stimulation to the sciatic nerve _.

A) may be observed by watching the contraction of the gastrocnemius muscle
B) may be observed by watching the nerve under a dissecting microscope
C) may be observed by simply looking at the nerve
D) may only be seen by recording the signal on an oscilloscope

Question 9

The difference between an action potential in a single axon and a compound action potential in a nerve is .

A) the action potential in the single axon is a graded event that increases with stimulus strength
B) the compound action potential in a nerve is graded, increasing with the stimulus strength
C) the compound action potential in a nerve is identical regardless of the stimulus strength to the nerve

Question 10

Curare causes paralysis .

A) by blocking the action potential in the nerve that serves a muscle
B) by blocking receptors on the postsynaptic cell
C) by blocking the release of neurotransmitter from the presynaptic cell
D) by blocking the action potential directly in the postsynaptic cell

Question 11

Where does ether exert its effects on nerve activity?

A) at the axon terminals of anesthetized fibers
B) everywhere along a nerve, when a segment of the nerve is anesthetized
C) in the anesthetized segment of a nerve, and distal to the anesthetized segment
D) only where it is in contact with the nerve

Question 12

When the sciatic nerve was chilled with iced Ringer's solution, _.

A) it became inexcitable or required a stimulus much greater than normal to produce a compound action potential
B) the compound action potential was unchanged
C) it became very excitable, generating large compound action potentials to small stimuli

Question 13

The expression "all-or-none" means that .

A) the action potential in a neuron may be larger or smaller depending on the amount of stimulation (it is graded)
B) the compound action potential in a nerve is graded
C) the compound action potential in a nerve always has the same shape and size (amplitude)
D) the action potential in a neuron always has the same shape and size (amplitude)

Question 14

During depolarization, the membrane potential is .

A) wavering up (positive) and down (negative)
B) becoming more positive
C) becoming more negative
D) unchanged

Question 15

If a stimulus to a neuron is great enough, _ is reached and an action potential is generated.

A) threshold
B) repolarization
C) depolarization
D) resting membrane potential

Question 16

When a neuron is in the resting state, .

A) both Na+ and K+ leak out of the cell
B) Na+ leaks into the cell and K+ leaks out of cell
C) Na+ leaks out of the cell and K+ leaks into the cell
D) both Na+ and K+ leak into the cell

Question 17

An action potential is .

A) a depolarization of the cell membrane
B) a refractory period of the cell membrane
C) a repolarization of the cell membrane
D) a rapid depolarization and repolarization of the cell membrane that is propagated

Question 18

An action potential results from _.

A) a change in the permeability of the neuron to K+ followed by a change in the permeability to Na+
B) a change in the permeability of the neuron to Na+ followed by a change in the permeability to K+
C) changes in the permeability of the neuron membrane to K+ alone
D) changes in the permeability of the neuron membrane to Na+ alone

Question 19

When a neuron is at rest, there is a charge separation (voltage) across the plasma membrane called .

A) repolarization
B) the battery
C) the resting membrane potential
D) depolarization

Question 20

During the time period immediately following an action potential, a neuron can produce another action potential only _.

A) if the neuron is stimulated again normally
B) if the neuron receives an especially strong stimulus
C) when the neuron is impermeable to K+
D) when the neuron remains very permeable to Na+

Question 21

In the experiment on stimulation of the isolated sciatic nerve, a compound action potential is produced. This represents _.

A) an artifact produced as a result of electrical stimulation
B) an action potential from a single axon
C) a summed electrical activity of all axons in the nerve

Question 22

In the experiment on stimulation of the isolated sciatic nerve, the compound action potential increases in amplitude with an increase in stimulation voltage. This is due to _.

A) recruitment of large diameter axons followed by small diameter axons in the nerve
B) increase in the size of action potentials produced be each individual axon in the nerve
C) simultaneous recruitment of small and large diameter axons in the nerve
D) recruitment of small diameter axons followed by large diameter axons in the nerve

Question 23

Resting membrane potential is maintained by the sodium-potassium pump, which transports

A) both Na+ and K+ out of the cell
B) Na+ into the cell and K+ out of the cell
C) Na+ out of the cell and K+ into the cell
D) both Na+ and K+ into the cell