Deck 19: Nerve Signaling

Question 1

The first event to occur when an adequate stimulus is applied to a neuron is:

A) the membrane potential moves immediately to a value of +30 mV.
B) the potassium channels open.
C) the sodium channels are inactivated.
D) some of the sodium channels at the point of stimulation open.

Answer 1

D

Question 2

Which is true of a neuron with a resting potential?

A) The cell membrane is permeable to Na+ but impermeable to K+ ions.
B) The outer surface of the plasma membrane has a negative charge.
C) The highest concentration of K+ is extracellular.
D) The sodium pump has moved Na+ to the outside of the plasma membrane.

Answer 2

D

Question 3

Excitatory neurotransmitters are most likely to:

A) increase the speed of impulse conduction.
B) make the cell membrane impermeable.
C) initiate an action potential.
D) make the resting potential more negative.

Answer 3

C

Question 4

Which of the following is not one of the main chemical classes of neurotransmitters?

A) Triglycerides
B) Amines
C) Amino acids
D) Neuropeptides

Question 5

During a relative refractory period:

A) the action potential cannot be initiated.
B) a resting potential exists.
C) the cell membrane is impermeable to Na+ and K+.
D) the action potential can be initiated with a strong stimulus.

Question 6

The only ion(s) that can diffuse across a neuron's membrane when the neuron is at rest is(are):

A) sodium.
B) potassium.
C) proteins.
D) phosphate.

Question 7

The neurotransmitter(s) that inhibit(s) the conduction of pain impulses is(are):

A) acetylcholine.
B) enkephalins.
C) dopamine.
D) norepinephrine.

Question 8

Within the nervous system, coding for the strength of a stimulus is accomplished through:

A) changes in the magnitude of the action potential.
B) changes in the length or duration of the action potential.
C) the frequency of nerve impulses.
D) an increase in the number of opening sodium channels.

Question 9

Which of the following is true of spatial summation?

A) Simultaneous stimulation of more than one postsynaptic neuron occurs.
B) Impulses are fired in a rapid succession by the same neuron.
C) Neurotransmitters released simultaneously from several presynaptic knobs converge on one postsynaptic neuron.
D) Speed of impulse transmission is increased when several neurotransmitters are released.

Question 10

When current leaps across an insulating myelin sheath from node to node, the type of impulse conduction is called:

A) repolarization.
B) refraction.
C) saltatory conduction.
D) diffusion.

Question 11

A slight shift away from the resting membrane potentials in a specific region of the plasma membrane is called a _____ potential.

A) membrane
B) resting membrane
C) local
D) None of the above is correct.

Question 12

Neurotransmitters are released in a synapse and bind to:

A) presynaptic terminals.
B) the synaptic cleft.
C) the base of the axon.
D) receptors on the postsynaptic neuron.

Question 13

The fastest nerve fibers in the body can conduct impulses up to approximately _____ meters per second.

A) 60
B) 85
C) 130
D) 190

Question 14

Which of the following statements about amino acid neurotransmitters is incorrect?

A) They are among the most common neurotransmitters in the central nervous system (CNS).
B) They are all inhibitory neurotransmitters.
C) Glycine is a widely distributed inhibitory neurotransmitter in the spinal cord.
D) All of the above statements are correct.

Question 15

A synaptic knob would be located on a(n):

A) cell body.
B) axon.
C) dendrite.
D) cell body, axon, or dendrite.

Question 16

When an impulse reaches a synapse:

A) two nerve fibers come in direct contact.
B) impulses will pass in either direction.
C) an electrical spark will jump the gap.
D) chemical transmitters are released.

Question 17

For a neurotransmitter to produce an inhibitory postsynaptic potential, which of the following channels must open?

A) Sodium and potassium channels
B) Potassium and/or chloride channels
C) Sodium and chloride channels
D) Only the sodium channels

Question 18

A synapse consists of:

A) a synaptic knob.
B) a synaptic cleft.
C) the plasma membrane of a postsynaptic neuron.
D) all of the above.

Question 19

Serotonin is an example of a(n):

A) amino acid neurotransmitter.
B) amine neurotransmitter.
C) acetylcholine derivative.
D) neuropeptide neurotransmitter.

Question 20

Which is true of an action potential?

A) The plasma membrane is impermeable to Na+ and K+ ions.
B) Na+ ions move extracellularly.
C) The charges become equal on the outside and inside of the plasma membrane.
D) The outside of the plasma membrane is negatively charged, and the inside is positively charged.

Question 21

The difference between sodium and potassium in the generation of action potential is that:

A) sodium causes repolarization of the cell membrane, and potassium causes depolarization of the cell membrane.
B) sodium causes unipolarization of the cell membrane, and potassium causes repolarization of the cell membrane.
C) sodium causes repolarization, and potassium is not required in the action potential mechanism.
D) sodium causes depolarization of the cell membrane, and potassium causes repolarization of the cell membrane.

Question 22

If the threshold potential is surpassed, the full peak of the action potential is always reached.

Question 23

The sodium-potassium pump actively pumps three potassium ions out of the neuron and two sodium ions into the neuron.

Question 24

The fastest nerve fibers in the body can conduct an impulse that is how much faster than the slowest fibers in the body?

A) Almost 50 times faster
B) Almost 100 times faster
C) Almost 300 times faster
D) Almost 500 times faster

Question 25

A synapse can occur only between an axon and:

A) a dendrite.
B) a cell body.
C) another axon.
D) any of the above.

Question 26

In depolarization the membrane potential moves toward zero, whereas in hyperpolarization the membrane potential moves away from zero.

Question 27

Which neuron could transmit a nerve impulse the fastest?

A) A small-diameter neuron without myelin
B) A large-diameter neuron without myelin
C) A large-diameter neuron with myelin
D) A small-diameter neuron with myelin

Question 28

Neurons are the only living cells that maintain a difference in the concentration of ions across their membranes.

Question 29

Severe depression can be caused by a deficit in certain brain synapses of:

A) acetylcholine.
B) amines.
C) amino acids.
D) neuropeptides.

Question 30

Stimulus-gated channels open in response to:

A) sensory stimuli.
B) the influx of potassium.
C) hyperpolarization.
D) both A and B.

Question 31

Acetylcholine is in the same class of neurotransmitters as:

A) serotonin.
B) histamine.
C) dopamine.
D) none of the above.

Question 32

When a neuron is resting, the inner surface of its plasma membrane is slightly positive compared with its outer surface.

Question 33

No impulse can be sent through a neuron:

A) during the relative refractory period.
B) when the charge of the neuron is -70.
C) during the absolute refractory period.
D) when the stimulus is too strong.

Question 34

A neurologist is using a voltmeter to measure potential. The membrane potential of a neuron was recorded at +30 mV. This is what type of membrane potential?

A) Action
B) Conduction
C) Polarized
D) Resting

Question 35

Which of the following is not used by the body as a neurotransmitter?

A) Nitric oxide
B) Peroxide
C) Carbon monoxide
D) All of the above are used by the body as neurotransmitters.

Question 36

Compared with the outside of the neuron, the inside has a(n) ____ charge.

A) positive
B) negative
C) equal
D) None of the above are correct.

Question 37

Which of the following antidepressants acts by blocking the action of monoamine oxidase (MAO)?

A) Phenelzine
B) Imipramine
C) Amitriptyline
D) Cocaine

Question 38

Dopamine, epinephrine, and norepinephrine are classified as:

A) acetylcholine.
B) neuropeptides.
C) catecholamines.
D) none of the above.

Question 39

The difference in electrical charge between the inside and outside of a membrane is called the membrane potential.

Question 40

The magnitude of the action potential peaks when the sodium channels close.

Question 41

A neurotransmitter can be excitatory or inhibitory, not both.

Question 42

The action potential is called an all-or-none response, because if the threshold potential is surpassed, the full peak of the action is always reached; if the threshold potential is not surpassed, no action potential will occur.

Question 43

Whether an impulse is continued through the neuron depends on the magnitude of the voltage in the axon hillock.

Question 44

A neurotransmitter can be either excitatory or inhibitory depending on the postsynaptic receptor.

Question 45

When epinephrine and norepinephrine are released into the bloodstream, they are called hormones instead of neurotransmitters.

Question 46

In a myelinated fiber, the action potential jumps from one node of Ranvier to the next.

Question 47

Excitatory neurotransmitters are most likely to initiate an action potential.

Question 48

The speed of a nerve impulse depends on the neuron's resting potential.

Question 49

The sensory fibers from the skin generally conduct impulses up to about 130 meters per second.

Question 50

The receptors embedded in the plasma membrane of a postsynaptic neuron are protein molecules.

Question 51

Myelinated fibers conduct impulses faster than unmyelinated fibers.

Question 52

Many anesthetics produce their effects by inhibiting the opening of the potassium channels, blocking the repolarization of nerve impulses.

Question 53

When a neuropeptide is secreted with one or two other neurotransmitters, it is thought to serve as a neuromodulator, regulating the effects of the other neurotransmitters.

Question 54

The neurotransmitter acetylcholine always has an excitatory effect.

Question 55

In a myelinated neuron, the impulse can travel under the myelin between nodes of Ranvier.

Question 56

Enkephalins and endorphins are subclasses of amines that are pain relievers.

Question 57

An inhibitory postsynaptic potential is produced through the hyperpolarization of the postsynaptic membrane.

Question 58

Spatial summation is the effect produced by a rapid succession of stimuli on a single postsynaptic neuron.

Question 59

A membrane that exhibits a membrane potential is said to be depolarized.

Question 60

Action potential and membrane potential are synonymous terms.

Question 61

An electrical synapse occurs when a strong action potential is able to arc across a small synaptic cleft.

Question 62

Glutamate is the most common excitatory neurotransmitter in the CNS.

Question 63

Many biologists believe that amino acids are among the most common neurotransmitters in the CNS.

Question 64

In the mature nervous system, electrical synapses can occur only where there are gap junctions.

Question 65

Electrical synapses can be found in muscle tissue.

Question 66

Cocaine produces a temporary feeling of well-being by blocking the release of dopamine.

Question 67

The neuron is able to maintain an internal negative charge by pumping out sodium (Na⁺) and pumping in chloride (Cl-).

Question 68

Myelinated axons without gaps in the myelin (nodes of Ranvier) conduct impulses more efficiently than axons with nodes of Ranvier.

Question 69

During the nerve impulse, the internal charge of the neuron becomes briefly positive.

Question 70

Action potential and nerve impulse are interchangeable terms.

Question 71

The resting potential of a neuron is maintained by having mostly negative ions on the inside and mostly positive ions on the outside.

Question 72

Action potentials travel in only one direction along a nerve fiber.

Question 73

Some neurotransmitters use cyclic adenosine monophosphate as a second messenger to cause a response in the postsynaptic cell.

Question 74

The opening of stimulus-gated channels is always followed by the opening of voltage-gated channels.

Question 75

There is a time when a neuron will not send a nerve impulse no matter how strong the stimulus is.

Question 76

All neurotransmitters are organic molecules.

Question 77

If a membrane exhibits a membrane potential, it is said to be polarized.

Question 78

Chemical synapses involve neurotransmitters.

Question 79

When a neuron is resting, its membrane potential is zero.

Question 80

In a synapse, both the presynaptic cell and postsynaptic cell must be neurons.