Deck 16: Neurophysiology of Nerve Impulses: Frog Subjects

Question 1

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

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

Answer 1

A

Question 2

Which nerve innervates the gastrocnemius muscle of the frog?

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

Answer 2

B

Question 3

An action potential results from _ .

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

Answer 3

C

Question 4

The neurotransmitter released from the axon terminal _ .

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

Question 5

During depolarization, the membrane potential is _ .

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

Question 6

Net movement of this ion is primarily associated with repolarization.

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

Question 7

Where does ether exert its effects on nerve activity?

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

Question 8

A compound action potential .

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

Question 9

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

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

Question 10

A neuron .

A)will generate an action potential every time it is stimulated
B)is absolutely refractory to stimulation during the time Na+ permeability is changing, and immediately following this change
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

Question 11

When a neuron is in the resting state, .

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

Question 12

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

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

Question 13

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

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

Question 14

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

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

Question 15

The effects of electrical stimulation to the sciatic nerve .

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

Question 16

An action potential is _ .

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

Question 17

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

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

Question 18

Neurons and other excitable cells respond to stimuli by producing _ .

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

Question 19

Curare causes paralysis .

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

Question 20

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)it became very excitable, generating large compound action potentials to small stimuli
C)the compound action potential was unchanged