Deck 10: Nervous System I: Basic Structure and Function

Question 1

Myelin is rich in ________.

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

Answer 1

C

Question 2

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

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

Answer 2

D

Question 3

The oculomotor nerve is a cranial nerve containing nerve fibers that innervate eye muscles and control eye movement. These fibers are examples of

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

Answer 3

C

Question 4

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 5

What structure supports the axon from within?

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

Question 6

Sensory receptors

A)send signals from the brain to muscles.
B)work with muscles to generate motion.
C)detect changes in and outside the body.
D)act as an intermediate within the CNS between the ascending and descending tracts.

Question 7

Masses of myelinated nerve fibers appear

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

Question 8

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.

Question 9

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 10

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 11

Which cells produce myelin in the brain and spinal cord?

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

Question 12

Most of the neurons in the brain and spinal cord are

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

Question 13

A neuron may have

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

Question 14

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 15

Every neuron has

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

Question 16

The nervous system

A)provides a support system for the body.
B)controls the movement of muscles.
C)contracts and generates a force to cause bodily motion.
D)provides nutrients and nourishment for surrounding cells.

Question 17

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.

Question 18

Dendrites on unipolar neurons are parts of

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

Question 19

In Guillain-Barre syndrome, the immune system attacks and degrades the myelin sheath of PNS axons. Predict the effect this will have on nerve impulse and motor function.

A)Lost insulation from myelin will cause neurons of the PNS to be hyper-excitable and muscular spasms will result.
B)Motor signals will not be sent from the brain down the efferent pathway because the brain cannot generate them.
C)The brain will slowly degrade and various brain functions will be lost, including motor functions.
D)Lost insulation from myelin will cause neurons of the PNS to lose saltatory conduction, resulting in poor muscle function.

Question 20

Which of the following is unique to neurons?

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

Question 21

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

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

Question 22

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 23

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 24

A neuron is stimulated, which changes membrane potential to the point where voltage-gated Na⁺ channels open and begin depolarizing the cell. The neuron has reached

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

Question 25

A neuron receives a series of stimuli that increases the membrane permeability of Na⁺, but not enough to cause membrane potential to surpass -55mV. This neuron is said to be

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

Question 26

A physiologist testing signal transduction rates in two different nerves notices that one fiber conducts signals much faster than the other. Which is the most likely difference between the two?

A)The faster nerve fiber has more axons.
B)The faster nerve fiber has more dendrites.
C)The faster nerve fiber is myelinated and the slower one is not.
D)The slower nerve fiber is myelinated and the faster one is not.

Question 27

A neuron receives a stimulation that causes Cl- channels to open, resulting in a hyperpolarization of the neuronal membrane. This situation is an example of a(n)

A)facilitated potential.
B)divergence.
C)excitatory postsynaptic potential.
D) inhibitory postsynaptic potential.

Question 28

A neuron is exposed to a drug that completely blocks voltage-gated potassium channels, but has no effect on non-gated channels or the sodium-potassium pump. Which of the following describes the effect on action potential generation?

A)Threshold will never be crossed, and therefore an action potential will never be generated.
B)Repolarization will never occur after threshold is crossed and sodium will continue to flow into the neuron.
C)Repolarization will still occur, but at an inefficiently slow rate.
D)Resting potential would not be maintained, as potassium could not leak out of the neuron.

Question 29

Presynaptic neurons release neurotransmitters by ________.

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

Question 30

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 31

The dendrites of a neuron interact with several different axon terminals. Some of them are sending excitatory signals, while others are sending inhibitory signals. Over the course of the effects of these signals, the neuronal membrane potential reaches around -90mV. This means, overall, that the neuron will be

A)excited enough to easily cross threshold and generate an action potential.
B)excited, but not enough to cross threshold.
C)stabilized to remain at resting potential.
D)inhibited from generating action potentials.

Question 32

A test organism develops a genetic mutation that causes neurons to develop without synaptic knobs. How will this impact neuronal function?

A)Signal transduction down the axon will be interrupted, so the signal will not "jump" the synapse and reach the postsynaptic neuron.
B)The dendrites of the postsynaptic neurons will have no means to attach to presynaptic axons.
C)No neurotransmitters will be released into the synapse to signal the postsynaptic neuron, as the synaptic knob is where they are stored.
D)Action potentials will not travel down the axon nearly as rapidly.

Question 33

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 fiber constitutes an impulse.

Question 34

The resting cell membrane is more permeable to which ion?

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

Question 35

A positive feedback loop occurs when the outcome of an event causes the event to continue occurring and amplifies its effects. Which of the following aspects of an action potential constitutes a positive feedback loop?

A)An initial flow of sodium ions into the neuron opens voltage-gated sodium channels, rapidly causing more sodium to enter.
B)Opening of voltage-gated sodium channels causes voltage-gated potassium channels to open and release potassium to the extracellular environment, slowly counteracting sodium influx.
C)The sodium-potassium pump exactly balances ion leaks by pumping three sodium and two potassium ions across the membrane.
D)The threshold potential is around -55mV.

Question 36

Organize the following list of nervous system elements by their classifications as CNS or PNS elements: oligodendrocytes, thermoreceptors (nerves that sense temperature), interneurons, satellite cells, brain, motor neurons.

A)CNS thermoreceptors, satellite cells, brain; PNS oligodendrocytes, interneurons, motor neurons
B)CNS satellite cells, brain, oligodendrocytes; PNS thermoreceptors, motor neurons, interneurons
C)CNS interneurons, satellite cells, motor neurons; PNS brain, oligodendrocytes, theromoreceptors
D)CNS brain, oligodendrocytes, interneurons; PNS thermoreceptors, satellite cells, motor neurons

Question 37

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

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

Question 38

Synaptic knobs are at the ends of

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

Question 39

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 40

Organize the following list of bodily functions and actions according to whether they are controlled by the somatic nervous system or autonomic nervous system: heart rate, walking, looking to the left, digestion, vasoconstriction, biceps femoris contraction.

A)Somatic heart rate, looking to the left, digestion; Autonomic biceps femoris contraction, walking, vasoconstriction
B)Somatic walking, looking to the left, biceps femoris contraction; Autonomic heart rate, digestion, vasoconstriction
C)Somatic heart rate, digestion, vasoconstriction; Autonomic walking, looking to the left, biceps femoris contraction
D)Somatic walking, heart rate, vasoconstriction; Autonomic looking to the left, biceps femoris contraction, digestion

Question 41

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.
D)an enzyme breaks down a neurotransmitter and then another enzyme builds it back up.

Question 42

A neuron in the aorta detects oxygen content in the blood and relays this information to the brain. This neuron is a ________ of the ________ pathway.

A)effector; afferent
B)effector; efferent
C)sensory receptor; afferent
D)sensory receptor; efferent

Question 43

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)cerebrovascular accident.

Question 44

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 45

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 46

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 47

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 48

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 49

The types of neurons that are organized into neuronal pools are

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

Question 50

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

A)Endorphin
B)Acetylcholine
C)Epinephrine
D)Dopamine

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

The neurotransmitter that controls skeletal muscle contraction is

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

Question 53

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 54

An action potential is triggered if

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

Question 55

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 56

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 57

If a resting potential becomes more negative, the membrane is

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

Question 58

A nerve cell membrane becomes depolarized as a result of

A)Ca⁺² leaving the nerve cell.
B)Na⁺ ion channels being opened and Na⁺ ions diffusing into the cell.
C)the relative ease with which K⁺ diffuses into the nerve cell.
D)Na⁺ being prevented from passing through the membrane.

Question 59

An excitatory postsynaptic potential lasts for about

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

Question 60

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 61

A nerve is a single neuron that transmits impulses.

Question 62

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 63

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

Question 64

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 65

Axon branches are called collaterals.

Question 66

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

Question 67

Nodes of Ranvier lie between neurons.

Question 68

A mixed nerve includes different neuroglial cells.

Question 69

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 70

Drugs that decrease membrane permeability to sodium

A)increase the amount of nerve impulses to/through an affected area.
B)increase pain.
C)lessen pain.
D)make pain-signalling neurons more excitable

Question 71

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

Question 72

The brain and spinal cord comprise the central nervous system.

Question 73

Sensory receptors are part of the CNS.

Question 74

A person is exposed to a drug that prevents vesicles from forming in neurons. Predict the effect this will have on nerve function.

A)Voltage-gated potassium channels will be blocked, slowing depolarization and slowing nerve impulses.
B)Neurons will be hyper-excitable.
C)Neurotransmitters won't be released into the synapse via exocytosis.
D)Action potentials will not be carried through the axon.

Question 75

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

Question 76

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

Question 77

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 78

Myelin is composed largely of carbohydrates.

Question 79

The space between neurons is called the neuronal space.

Question 80

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