Deck 10: Nervous System I: Basic Structure and Function

Question 1

A reason that the axons in the CNS and PNS differ in their ability to regenerate after injury is that

A) axons of the CNS lack myelin.
B) axons of the CNS lack neurilemmae.
C) peripheral nerves lack Schwann cells.
D) peripheral nerves lack endoneurium.

Answer 1

B

Question 2

The functional connection between two neurons is a

A) dendrite.
B) gap junction.
C) synapse.
D) neurotransmitter.

Answer 2

C

Question 3

The cytoplasmic extensions that, together with the cell body, provide the main receptive surfaces for neurons are

A) neurofibrils.
B) chromatophilic substance (Nissl bodies).
C) axons.
D) dendrites.

Answer 3

D

Question 4

Most of the neurons in the brain and spinal cord are

A) bipolar.
B) unipolar
C) multipolar.
D) nonpolar.

Question 5

_________ support the axon from within.

A) Dendrites.
B) Nodes of Ranvier.
C) Neurofibrils.
D) Collaterals.

Question 6

Myelin is rich in ___________.

A) nucleic acids
B) carbohydrates
C) lipids
D) salts

Question 7

Sensory receptors

A) monitor light
B) monitor sound.
C) detect changes in and outside the body.
D) all of the above.

Question 8

In order for a severed peripheral nerve to regenerate and recover its original function, nerve fibers must sprout and enter tubes formed by

A) basement membranes and connective tissues.
B) former axons.
C) myelin.
D) nodes of Ranvier.

Question 9

Three general functions of the nervous system are

A) sensory, motor, and predictive.
B) integrative, motor, and sensory.
C) predictive, manipulative, and integrative.
D) reflexive, sensory, and predictive.

Question 10

Myelin

A) is released from a neuron and travels to another neuron.
B) consists of layers of lipids and proteins that wrap around an axon.
C) is produced in response to bacterial infection.
D) is a form of chromatophilic substance that fills Schwann cells.

Question 11

A myelinated nerve fiber is ______, whereas an unmyelinated nerve fiber is ______.

A) gray, and composing the gray matter of the brain and spinal cord; white, and composing the white matter of the brain and spinal cord
B) white, and composing the gray matter of the brain and spinal cord; gray, and composing the white matter of the brain and spinal cord
C) white, and composing the white matter of the brain and spinal cord; gray, and composing the gray matter of the brain and spinal cord
D) white, and composing the gray matter of the brain and spinal cord; red, and composing the white matter of the brain and spinal cord

Question 12

The nervous system

A) detects changes in the internal or external environment.
B) controls the movement of muscles.
C) integrates information from several sources and uses it to determine an appropriate response.
D) all of the above.

Question 13

Masses of myelinated nerve fibers appear

A) white.
B) gray.
C) brown.
D) transparent.

Question 14

Which cells produce myelin in the brain and spinal cord?

A) Schwann cells
B) Astrocytes
C) Microglia
D) Oligodendrocytes

Question 15

Which of the following is(are) a type of neuroglia?

A) Astrocyte
B) Oligodendrocyte
C) Schwann cell
D) All of the above

Question 16

Every neuron has

A) many axons.
B) a cell body.
C) myelin.
D) a neurilemma.

Question 17

Which of the following is unique to neurons?

A) Golgi apparatus
B) Chromatophilic substance
C) Mitochondrion
D) Lysosome

Question 18

A neuron may have

A) one axon and many dendrites.
B) one dendrite and many axons.
C) no dendrites.
D) no axons.

Question 19

Neurons that conduct impulses from the CNS to muscles or glands are

A) sensory neurons.
B) interneurons.
C) motor neurons.
D) unipolar neurons.

Question 20

The two types of cells of the nervous system are

A) axons and dendrites.
B) neurons and neuroglia.
C) motor neurons and sensory neurons.
D) Schwann cells and microglia.

Question 21

Synaptic knobs are at the ends of

A) axons.
B) dendrites.
C) cell bodies.
D) neuroglia.

Question 22

Which of the following neuroglia are not part of the CNS?

A) Ependymal cells
B) Astrocytes
C) Satellite cells
D) Microglia

Question 23

Each neuron in the CNS may receive input from

A) only one synaptic knob.
B) one synaptic knob at each end.
C) about 10 dendrites.
D) thousands of axons.

Question 24

A stimulus great enough to change the membrane potential and propagate an action potential is said to have reached _________.

A) recruitment
B) threshold
C) summation
D) tetanus

Question 25

An excitatory postsynaptic potential lasts for about

A) 15 minutes.
B) 15 seconds.
C) 15 milliseconds.
D) 15 microseconds.

Question 26

Clusters of neuron cell bodies in the PNS are called _____.

A) neuromas
B) axons
C) ganglia
D) nuclei

Question 27

Which of the following ions cross neuron cell membranes most readily?

A) Potassium
B) Sodium
C) Calcium
D) Magnesium

Question 28

Which of the following molecules is responsible for "runner's high," a good feeling that accompanies long-distance running?

A) Beta endorphin
B) Acetylcholine
C) Epinephrine
D) Dopamine

Question 29

What is the correct sequence of events along an axon that follows a membrane reaching threshold potential? 1. The membrane depolarizes.
2) Sodium channels open and sodium ions diffuse inward.
3) The membrane repolarizes.
4) Potassium channels open and potassium ions diffuse outward.

A) 3, 2, 4, 1
B) 2, 1, 4, 3
C) 1, 2, 4, 3
D) 4, 1, 3, 2

Question 30

Dendrites on unipolar neurons are parts of

A) sensory neurons.
B) motor neurons.
C) interneurons.
D) efferent neurons.

Question 31

A nerve cell membrane becomes depolarized as a result of

A) calcium leaving the nerve cell.
B) some ion channels being opened while others are closed.
C) the relative ease with which K⁺ diffuses into the nerve cell.
D) Na⁺ being prevented from passing through the membrane.

Question 32

If a neuron receives a series of stimuli whose effect is excitatory but subthreshold, the neuron is more excitable to incoming stimulation than before and is said to be

A) graded.
B) amplified.
C) facilitated.
D) refractory.

Question 33

If a resting potential becomes more negative, the membrane is

A) depolarized.
B) hyperpolarized.
C) repolarized.
D) summated.

Question 34

The most rapid conduction of an impulse along an axon occurs on a fiber that is

A) thick and myelinated.
B) thick and unmyelinated.
C) thin and myelinated.
D) thin and unmyelinated.

Question 35

Which of the following cells is found only in the PNS?

A) Oligodendrocyte
B) Astrocyte
C) Microglial cell
D) Schwann cell

Question 36

Action potentials are related to impulses conducted along an axon in that

A) many impulses are required to cause one action potential.
B) active transport of Na⁺ and K⁺ are required for impulse conduction but not for an action potential.
C) impulses are stronger responses than are action potentials.
D) propagation of a series of action potentials along a nerve cell fiber constitutes an impulse.

Question 37

When an action potential passes over the surface of a synaptic knob, the contents of the vesicles are released in response to the presence of

A) calcium ions.
B) sodium ions.
C) neurotransmitters.
D) neuropeptides.

Question 38

Saltatory conduction

A) occurs only if the myelin sheath is continuous.
B) occurs only if nodes of Ranvier are lacking.
C) is faster than conduction on an unmyelinated fiber.
D) is slower than conduction on an unmyelinated fiber.

Question 39

Presynaptic neurons release neurotransmitters by ______________.

A) endocytosis.
B) exocytosis.
C) diffusion.
D) active transport.

Question 40

Transmitting an impulse from one neuron to another involves a(n)

A) impulse stimulating presynaptic dendrites to release a neurotransmitter into a synaptic cleft.
B) impulse stimulating a presynaptic axon to release a neurotransmitter into a synaptic cleft.
C) neurotransmitter traveling from presynaptic dendrites across a synapse to postsynaptic axons or a cell body.
D) neurotransmitter traveling from postsynaptic axons across a synapse to presynaptic dendrites or a cell body.

Question 41

Drugs that increase the actions of norepinephrine and/or serotonin by keeping them in synapses longer are most likely used to treat

A) multiple sclerosis.
B) Tay-Sachs disease.
C) clinical depression.
D) erectile dysfunction.

Question 42

In reuptake

A) an action potential reverses direction.
B) a neuropeptide breaks down into amino acids, which act as neurotransmitters.
C) a neurotransmitter that has already been released into the synaptic cleft is taken back into the synaptic knob of the presynaptic neuron or into nearby neuroglia or neurons.
D) an enzyme breaks down a neurotransmitter and then another enzyme builds it back up.

Question 43

Opiate drugs derived from poppies relieve pain in humans because the human nervous system has

A) neurotransmitters.
B) receptors for endogenous opiates.
C) myelin.
D) sodium and potassium membrane channels.

Question 44

An action potential is triggered if

A) EPSPs overpower IPSPs.
B) IPSPs overpower EPSPs.
C) chloride channels open.
D) the membrane hyperpolarizes.

Question 45

Migraine results from

A) release of calcitonin gene-related peptide from the trigeminal nerves at the base of the brain, in response to a spreading wave of excitation followed by lack of response from the cortex.
B) not eating enough chocolate, which causes a spreading effect in the cortex.
C) a neurotransmitter deficiency.
D) release of an abnormal form of beta endorphin from the trigeminal nerves at the base of the brain, in response to cortical stimulation.

Question 46

Viagra is a drug used to treat erectile dysfunction by dilating arteries in the penis. The neurotransmitter that Viagra affects is

A) acetylcholine.
B) nitric oxide.
C) serotonin.
D) histamine.

Question 47

The neurotransmitter most likely produced when a person uses a drug that creates a sense of well-being is

A) glutamic acid.
B) dopamine.
C) enkephalin.
D) substance Q.

Question 48

The types of neurons that are organized into neuronal pools are

A) interneurons.
B) intraneurons.
C) Schwann cells.
D) astrocytes.

Question 49

Neuroglia are specialized to react to environmental change, and neurons support neuroglia.

Question 50

A nerve is a single neuron that transmits impulses.

Question 51

Drugs that inhibit the enzyme monoamine oxidase

A) allow increased activity of norepinephrine.
B) decompose norepinephrine.
C) decrease the activity of serotonin.
D) decompose serotonin.

Question 52

Neurotransmitters that are modified amino acids are

A) dopamine, serotonin, epinephrine, and norepinephrine.
B) enkephalins, endorphins, and substance P.
C) aspartic acid, glutamic acid, glycine, and GABA.
D) potassium, sodium, and calcium ions

Question 53

Drugs that decrease membrane permeability to sodium

A) are used as local anesthetics.
B) prevent nerve impulses from passing through the affected body part.
C) lessen pain.
D) all of the above.

Question 54

Neural stem cells can be harvested from autopsies and stored, alive, in banks, whereas neurons cannot, because

A) people do not will them to science.
B) neural stem cells have lower oxygen and energy requirements than neurons.
C) neural stem cells have higher oxygen and energy requirements than neurons.
D) neural stem cells have more globular shapes than neurons.

Question 55

An immune response that affects the myelin coating on axons throughout the spinal cord and brain, triggering inflammation and leaving scars, is

A) muscular dystrophy.
B) multiple sclerosis.
C) Alzheimer disease.
D) amyotrophic lateral sclerosis.

Question 56

Marjorie takes an anti-anxiety drug so that she can sleep better and remain calm enough to study effectively. She begins by taking 25 milligrams every evening, but within a month this dose is no longer helping, so she takes two pills. After another month this dosage is no longer effective. This is happening because

A) her immune system is rejecting the drug.
B) she has developed tolerance, which means that her liver can no longer metabolize the drug, so it remains active for too long.
C) the number of receptors to which the drug binds on neurons has declined.
D) the number of receptors to which the drug binds on neurons has increased.

Question 57

Convergence refers to

A) dendrites from neurons in different parts of the nervous system contacting the same neuron.
B) axons from neurons in different parts of the nervous system contacting the same neuron.
C) dendrites from the same neuron touching each other.
D) a neuroglial cell that contacts many neurons.

Question 58

A drug that functions as an agonist

A) activates a receptor, helping a neurotransmitter bind or triggering an action potential in some other way.
B) causes great pain if taken in too high a dose.
C) blocks a receptor so that the neurotransmitter cannot bind.
D) relieves pain.

Question 59

Diverging axons amplify an impulse by

A) contacting many neurons.
B) returning the impulse to the neuron of origin.
C) splitting into multiple axons.
D) stimulating themselves.

Question 60

The neurotransmitter that controls skeletal muscle contraction is

A) beta endorphin.
B) nitric oxide.
C) acetylcholine.
D) GABA.

Question 61

The cells in the nervous system that fill spaces and support neurons both physically and nutritionally are called ______.

Question 62

Myelin is composed largely of carbohydrates.

Question 63

A mixed nerve includes different neuroglial cells.

Question 64

Sensory receptors are part of the CNS.

Question 65

The brain and spinal cord comprise the central nervous system.

Question 66

Nodes of Ranvier lie between neurons.

Question 67

The difference in electrical charge between the inside and outside of a polarized neuron cell membrane is called the ______ ______.

Question 68

Muscles and glands that respond to nervous stimulation are called _______.

Question 69

Several nerve fibers converging onto one neuron amplifies impulses.

Question 70

Astrocytes structurally support neurons and also provide important signals and nutrients to neurons.

Question 71

Enkephalins are neuropeptides.

Question 72

In convergence, two or more incoming fibers contact a single neuron, whereas in divergence, impulses leaving a neuron pass into several output fibers.

Question 73

The somatic nervous system controls voluntary actions and the autonomic nervous system oversees involuntary actions.

Question 74

Axon branches are called collaterals.

Question 75

During the absolute refractory period, a stimulus of high intensity may trigger a nerve impulse.

Question 76

Interneurons are specialized to carry impulses from receptor cells into the brain or spinal cord.

Question 77

Because the response of a nerve fiber is all-or-none, a greater intensity of stimulus does not produce a stronger impulse.

Question 78

Sheaths of ______ cells often enclose the larger axons outside of the brain and spinal cord.

Question 79

The space between neurons is called the neuronal space.

Question 80

A(n) ______ is the junction between neurons.