Deck 42: The Nervous System

Question 1

You dissect the brain of a mutant mouse and find that parts of the "white matter" look gray.What is a likely cause?

A)defects in myelination
B)peripheral nerve damage
C)oversized dendrites
D)excess myelination
E)excess neuronal proliferation

Answer 1

A

Question 2

What are the branched extensions of a neuron that receive signals called?

A)axons
B)cell bodies
C)dendrites
D)oligodendrocytes
E)synapses

Answer 2

C

Question 3

At myelinated areas of the axon (i.e.between nodes of Ranvier),which of the following statements is true?

A)There is an increased number of voltage-gated sodium channels.
B)There is increased resistance across the membrane.
C)There is increased capacitance across the membrane.
D)There is increased transport of potassium across the membrane.

Answer 3

B

Question 4

What diffuses across the narrow synaptic cleft between the presynaptic axon and the postsynaptic cell to transmit a nerve impulse?

A)neurotransmitter
B)electrical impulse
C)Na⁺ ion
D)vesicle
E)action potential

Question 5

What are examples of cells that support neurons both structurally and functionally?

A)dendrites and nodes of Ranvier
B)neuroglia and nodes of Ranvier
C)Schwann cells and dendrites
D)dendrites,nodes of Ranvier,and neuroglia
E)Schwann cells,oligodendrocytes,and other neuroglia

Question 6

In vertebrates,the ________ nervous system is composed of the brain and the spinal cord.

A)peripheral
B)central
C)somatic
D)autonomic
E)sympathetic

Question 7

When neurons are not producing electrical signals,there is still a voltage difference across their membranes.What is this voltage called?

A)channel-gate bias
B)electrolyte voltage
C)equilibrium potential
D)resting potential
E)ion current

Question 8

When acetylcholine stimulates the opening of ligand-gated ion channels on a postsynaptic cell,what is this event called?

A)neuromuscular junction
B)temporal summation
C)inhibitory postsynaptic potential (IPSP)
D)excitatory postsynaptic potential (EPSP)
E)synaptic integration

Question 9

What is the name for the gap into which neurotransmitters are released?

A)gap junction
B)synaptic cleft
C)postsynaptic membrane
D)presynaptic membrane
E)impulse channel

Question 10

Which ion channel is primarily responsible for the action potential?

A)the voltage-gated sodium channel
B)the voltage-gated potassium channel
C)the ligand-gated sodium channel
D)the ligand-gated potassium channel
E)the nongated sodium channel

Question 11

Nerve impulses are electrical signals measured across which structure?

A)lipid sheath of Schwann cell
B)plasma membrane of neuron
C)synapse
D)neuromuscular junction

Question 12

Which diagram correctly illustrates the distribution of ions in a resting neuron? (Note: A larger symbol indicates a higher concentration of that ion.)

A)A
B)B
C)C
D)D

Question 13

Which of the following characteristics are true for an action potential? I-A threshold potential must be exceeded for an action potential to occur.
II-A stimulus either produces a full action potential or none at all.
III-During the refractory period it is less likely that stimuli can produce another action potential.

A)I only
B)I and II
C)II and III
D)I and III
E)I,II,and III

Question 14

What is the elongated extension of a neuron that nerve impulses travel along?

A)axon
B)cell body
C)dendrite
D)oligodendrocyte
E)synapse

Question 15

Which figure correctly illustrates the mechanism of action of the sodium-potassium pump?

A)A
B)B
C)C
D)D

Question 16

The membrane of a resting neuron is most permeable to which of the following ions?

A)Cl^-
B)Ca²⁺
C)Na⁺
D)K⁺
E)H⁺

Question 17

Which neurotransmitter is released from a motor neuron at the neuromuscular junction?

A)acetylcholine
B)GABA
C)ephinephrine
D)dopamine
E)serotonin

Question 18

What is the process in which impulses jump from node to node?

A)facilitated transmission
B)refractory action
C)incomplete transfer
D)repolarization
E)saltatory conduction

Question 19

What determines the direction of the voltage change that occurs at the postsynaptic membrane?

A)the type of neurotransmitter
B)the type of second messenger system used
C)the type(s)of ions that travel through opened channels
D)the number of ion channels on the postsynaptic membrane

Question 20

Place the following events that occur at the vertebrate neuromuscular junction in the correct order. I-Depolarization of the muscle fiber membrane.
II-Generation of an action potential in the neuron.
III-Stimulation of Ca²⁺ entry into the neuron.
IV-Release of acetylcholine into the synapse.

A)I,II,III,IV
B)III,II,IV,I
C)I,III,IV,II
D)IV,II,III,I
E)II,III,IV,I

Question 21

Which region of the CNS listed below is NOT correctly paired with its function?

A)Broca's and Wernicke's areas-language and speech
B)Hypothalamus-regulates body temperature,appetite,and sleep
C)Cerebellum-relay station for ascending and descending tracts
D)Corpus callosum-connects the two brain hemispheres
E)Hippocampus-memory

Question 22

Which major regions compose the contemporary vertebrate brain?

A)rhombencephalon and prosencephalon only
B)mesencephalon and rhombencephalon only
C)prosencephalon and metencephalon only
D)metencephalon,rhombencephalon,and prosencephalon
E)rhombencephalon,mesencephalon,and prosencephalon

Question 23

The hippocampus,amygdala,and hypothalamus are the major components of the ________ system.

A)sympathetic
B)reflex
C)parasympathetic
D)limbic
E)autonomic

Question 24

A region of the brain receives both sensory information from ascending nerve tracts and motor commands from the cortex and cerebellum.This region plays an important role in motor control.Which region is it?

A)basal ganglia
B)pituitary gland
C)parietal lobe
D)thalamus
E)medulla oblongata

Question 25

What is the site of primary sensory integration in the brain?

A)medulla oblongata
B)cerebrum
C)cerebellum
D)thalamus
E)corpus callosum

Question 26

Which of the following is NOT a feature of the limbic system?

A)contains hippocampus and amygdala
B)resides deep within the cerebrum
C)responsible for emotional responses
D)important in the formation and recall of memories
E)part of the hypothalamus

Question 27

The spinal cord is enclosed by the vertebral column and layers of protective membranes.What are these membranes called?

A)neural net
B)white matter
C)dorsal root
D)meninges
E)viscera

Question 28

Which of the following structures is NOT a component of the hindbrain?

A)pons
B)medulla oblongata
C)ascending tracts
D)cerebellum

Question 29

The doctor informs you that your grandmother's stroke has caused damage to Wernicke's area.Which activity is likely to become more difficult for her?

A)walking
B)doing laundry
C)having a conversation
D)sleeping
E)mathematical calculations

Question 30

Where do correlation,association,and learning occur in the brain?

A)cerebellum
B)corpus callosum
C)medulla
D)cerebrum
E)pons

Question 31

What is the primary function of the hindbrain in vertebrates?

A)temperature control
B)integration of sensory data
C)memory storage
D)control of the heartbeat
E)coordination of motor reflexes

Question 32

What region of the brain integrates visceral activities,body temperature,and heartbeat?

A)medulla oblongata
B)cerebrum
C)hypothalamus
D)thalamus
E)corpus callosum

Question 33

Place the following events involved in drug addiction in the correct sequence. I-The synapse becomes less sensitive,and normal function can only continue in the presence of the drug.
II-CNS responds to increased firing by decreasing the number of drug receptors on the cell membrane.
III-Drug molecule prevents receptor endocytosis and causes overstimulation of the postsynaptic cell.

A)I,II,III
B)III,II,I
C)II,III,I
D)III,I,II

Question 34

Which animal phylum lacks a network of nerve cells for gathering information from the environment?

A)Porifera - sponges
B)Cnidaria - jellyfish,sea anemones
C)Platyhelminthes -- flatworms
D)Nematoda - roundworms
E)Mollusca - octopus,squid,clams,snails,and other mollusks

Question 35

Which of the following are examples of biogenic amines?

A)epinephrine and endorphins
B)GABA and serotonin
C)epinephrine,dopamine,and GABA
D)epinephrine,dopamine,and serotonin
E)epinephrine,norepinephrine,dopamine,and serotonin

Question 36

Damage to the substantia nigra,a specific region of the basal ganglia,can produce the resting muscle tremors characteristic of what disease?

A)epilepsy
B)Parkinson disease
C)seizures
D)Alzheimer disease
E)insomnia

Question 37

Which area of the cerebral cortex is important for the formulation of thoughts into speech?

A)Broca's area
B)the pons
C)the medulla oblongata
D)Wernicke's area
E)the cerebellum

Question 38

Which of the following drugs has been discovered to bind to acetylcholine receptors?

A)serotonin reuptake inhibitors
B)thorazine
C)cocaine
D)codeine
E)nicotine

Question 39

Where did information processing become increasingly centered in terrestrial vertebrates?

A)thalamus
B)forebrain
C)midbrain
D)hindbrain
E)medulla oblongata

Question 40

In early vertebrates,which component of the brain was devoted largely to coordinating motor reflexes?

A)thalamus
B)forebrain
C)midbrain
D)hindbrain
E)medulla oblongata

Question 41

Choose the two primary factors that contribute to the resting membrane potential of a neuron.

A)K⁺ leak channels make the cell membrane more permeable to K⁺.
B)The sodium-potassium pump exports 3 K⁺ from the cell for every 2 Na⁺ it imports
C)Na⁺ leak channels make the cell membrane more permeable to Na⁺.
D)K⁺ leak channels cause a higher concentration of K⁺ outside the cell.
E)The sodium-potassium pump exports 3 Na⁺ from the cell for every 2 K⁺ it imports

Question 42

How can mutations in different genes,functioning in different cells,lead to the same disease? From the following,choose the best responses to complete the sentences: "Physiological function requires that multiple cells work together.Various defects in different cells can impair function,leading to ________ that are indistinguishable at the level of the whole organism.In Charcot-Marie-Tooth disease,motor nerve function can be impaired either by a problem within ________,or a problem in ________ causing ________."

A)defects; somatic cells; oligodendrocytes; demyelination
B)symptoms; motor neurons; Schwann cells; demyelination
C)symptoms; sensory neurons; Schwann cells; fast axonal transport
D)genotypes; dendrites; axons; fast axonal transport

Question 43

Is the resting membrane potential of a neuron closer to the equilibrium potential for K⁺ or Na⁺?

A)K⁺
B)Na⁺
C)It is an average of the two.

Question 44

Which division of the nervous system regulates the activity of smooth muscle,cardiac muscle,and glands?

A)antagonistic nervous system
B)autonomic nervous system
C)sympathetic nervous system
D)parasympathetic nervous system
E)limbic nervous system

Question 45

A patient suffers from a disease that slows fatty acid synthesis.What is a likely impact of this disease on nervous system function?

A)improved functioning due to a healthier weight
B)insufficient myelination and slow axon conduction rate
C)improved functioning due to better blood flow
D)weaker action potentials with smaller depolarization

Question 46

A neuron that engages in spatial summation acquires a mutation that causes dendrite overgrowth and promiscuous synapsing.What is the likely outcome?

A)abnormally low frequency of action potentials
B)summation will not occur
C)abnormally high frequency of action potentials
D)action potentials with stronger depolarization

Question 47

neurons are the only electrically-active cells.

Question 48

Genetic studies have found that Charcot-Marie-Tooth may be caused by a mutation in the gene Mitofusin-2 (MFN2),which causes mitochondria to form large clumps.In what area of a neuron are these clumps most likely to cause a problem?

A)axon
B)synapse
C)soma
D)dendrite
E)myelin

Question 49

What additional factor is required to mediate the parasympathetic effects of acetylcholine?

A)G-protein coupled receptor
B)GABA
C)AMPAR
D)habituation
E)synaptic integration

Question 50

Subsequent to motor neuron degeneration in Charcot-Marie-Tooth disease,muscles begin to weaken and degenerate as well.What is the likely cause?

A)Muscles will atrophy if they don't receive regular stimulation from motor neurons.
B)Muscles require healthy Schwann cells for myelination as well.
C)Muscles contain large numbers of mitochondria.
D)Toxins leak out from the dying motor neurons onto the muscles.

Question 51

When a neuron is not firing,the sodium-potassium pump is inactive.

Question 52

What is the likely impact of this toxin on action potentials?

A)They will occur more frequently.
B)They will be stronger and more unpredictable.
C)Without ion gradients,action potentials are not possible.
D)They will have longer refractory periods.

Question 53

Three-quarters of the substantial amount of energy consumed by the brain is used to run a single molecular machine that maintains the resting potential of neurons.What is this machine called?

A)K⁺ leak channel
B)sodium-potassium pump
C)acetylcholine receptor
D)voltage-gated sodium channel
E)voltage-gated calcium channel

Question 54

Your roommate is on an ultra-low fat diet to try to lose weight.Given what you know about structure of the nervous system,what advice would you give him?

A)"You should drink large quantities of water,because the brain is mostly water."
B)"Good for you! Losing weight by any means necessary can only help your brain."
C)"You should eat some healthy unsaturated fats,like those found in fish,olive oil,and nuts,because your brain needs fatty acids to build the myelin sheaths around your axons."
D)"You should eat trans fats,from donuts,because 'trans' is short for neurotransmission."

Question 55

Which of the following is not part of the peripheral nervous system?

A)sympathetic division of the autonomic nervous system
B)spinal cord
C)parasympathetic division of the autonomic nervous system
D)somatic nervous system
E)sensory pathways

Question 56

Mutation of the peripheral myelin protein 22 (PMP22)gene,which causes demyelination of peripheral neurons,is a more common cause of Charcot-Marie-Tooth disease.In which cells is the PMP22 gene important for normal function?

A)Schwann cells
B)preganglionic neurons
C)postganglionic neurons
D)oligodendrocytes
E)interneurons

Question 57

Which of the following targets is NOT regulated by the autonomic nervous system?

A)skeletal muscles
B)cardiac muscles
C)glands of the body
D)smooth muscles
E)none of these

Question 58

To process information,postsynaptic neurons often add up simultaneous signals from several presynaptic neurons.Which structure and process allow them to do so?

A)axons; temporal summation
B)axons; spatial summation
C)dendrites; temporal summation
D)dendrites; spatial summation

Question 59

"Synapses are connections between the axon of one neuron and the dendrite of another neuron,where neurotransmitters transmit a chemical signal." How would you modify this statement to make it more complete? (Check all that apply.)

A)The statement needs no modification.
B)Synapses can also form between an axon and a cell soma.
C)Neuromuscular synapses form between the axon of a neuron and a muscle.
D)Synapses often form among the parts of a single cell.
E)Synapses can be electrical as well as chemical.

Question 60

What important resource do Schwann cells and oligodendrocytes provide to neurons?

A)oxygen
B)nutrients
C)physical strength from microtubules
D)Ca²⁺ currents
E)insulating layers of membrane

Question 61

How do temporal and spatial summation improve the processing power of the brain?

A)Temporal summation allows circadian rhythms to regulate neuronal activity.Spatial summation allows latitude to regulate neuronal activity.
B)Temporal summation allows a neuron to fire prolonged action potentials,and spatial summation allows a neuron to synapse onto new targets.
C)Temporal and spatial summation both make the neuron more likely to fire action potentials.
D)Temporal summation allows a neuron to recognize a persistent signal from a single presynaptic cell,and spatial summation allows a neuron to recognize a broad signal from multiple presynaptic cells.

Question 62

Sodium ions are single atoms.Why can't they simply diffuse through the cell membrane's lipid bilayer?

A)Since they are charged,ions can't cross the hydrophobic center of the membrane without a channel or pump.
B)Sodium ions are covalently attached in groups of three,which are too large to diffuse easily.
C)Ions do traverse the membrane easily,but the sodium-potassium pump moves them back across.
D)Chelator proteins capture any ions that start to cross the bilayer.

Question 63

What does the Nernst equation allow us to do?

A)Predict the function of a specific type of neuron.
B)Calculate the equilibrium potential for an ion.
C)Use a computer program to model axonal transmission.
D)Calculate the magnitude of depolarization during an action potential.

Question 64

If sympathetic and parasympathetic neurons both release acetylcholine (ACh),how can they have antagonistic effects? (Check all that apply.)

A)The target cells of each set of neurons respond differently to the same signal.
B)Each type of neuron secretes ACh bound to a different co-neurotransmitter.
C)Sympathetic neurons activate the adrenal gland,causing secretion of epinephrine.
D)The neurons release different forms of ACh.
E)Parasympathetic neurons activate the adrenal gland,causing secretion of epinephrine.

Question 65

Another toxin that also blocks neurotransmitter release is tetanus toxin; however,it primarily affects inhibitory interneurons of the spinal cord that negatively regulate motor neurons.Which would be symptoms of tetanus toxin poisoning?

A)flaccid paralysis
B)spastic paralysis
C)slowed action potential conduction
D)pupil dilation

Question 66

In contrast to these toxins,strychnine acts postsynaptically,to block glycine from binding to receptors on motor neurons.Would you expect the symptoms of strychnine poisoning to be more similar to those of botulinum or tetanus toxin?

A)botulinum
B)tetanus toxin

Question 67

What limits the frequency of action potentials?

A)chloride ions
B)spike amplitude
C)nodes of Ranvier
D)refractory period

Question 68

Why are mammalian reflexes so fast? (Check all that apply.)

A)They use neurons with extra-wide axons.
B)They complete the sensory input-to-motor output circuit in only 2-3 neurons.
C)They do not send signals to the brain and back.
D)They activate a large number of sensory neurons,which speeds things up after the motor neuron performs spatial summation.
E)There was a selective advantage to evolve rapid responses to certain types of stimuli.

Question 69

K⁺ channels in the heart do not have binding sites for ACh,yet parasympathetic release of ACh causes outward flux of K⁺ from heart cells.How does this occur?

A)ACh triggers release of epinephrine from the adrenal glands,which in turn causes K+ flux out of heart cells.
B)ACh binds to a G-protein coupled receptor on heart cells,and the G protein alpha subunit binds to a separate K⁺ channel and causes it to open.
C)Parasympathetic neurons activate sympathetic neurons,which directly cause K⁺ flux from heart cells.
D)ACh binds and activates a K⁺ pump on heart cells.

Question 70

When an action potential begins and sodium channels open,why does sodium rush into the cell? (Check all that apply.)

A)The inside of the cell is negatively charged.
B)The inside of the cell is positively charged.
C)Chloride ions are waiting to bind to the sodium inside the cell.
D)The diffusion gradient drives sodium into the cell.
E)Channels use energy to move ions across the membrane whenever they are open.

Question 71

Since there is a larger concentration of potassium ions inside a neuron,why is the inside of the neuron negative (-70mV)relative to the outside?

A)Potassium ions carry a negative charge.
B)Negatively-charged proteins inside the cell counteract the charge of the potassium ions.
C)The negative sign is just a historical convention.
D)The high concentration of sodium ions outside the cell makes the inside negative by comparison.

Question 72

A patient of yours is injured in a car accident.The surgeon reports that while there is damage to the dorsal roots,the spinal cord and nerves otherwise appear intact.What functions would you expect to be affected in the patient?

A)The patient may lose somatic function,but should retain autonomic function.
B)The patient may lose motor function,but should retain sensory perception.
C)The patient may lose some sensory perception,but should retain motor function.However,lack of proprioceptive input may make muscle control difficult.
D)The patient may lose parasympathetic function,but should retain sympathetic function.They should avoid stressful situations.

Question 73

What would happen if the G-protein coupled receptor in heart cells that binds to ACh had a mutation that caused it to bind more tightly to the G-protein alpha subunit?

A)G-protein activation and K+ channel opening would happen more quickly.Heart rate may remain abnormally low,impairing response to stress.
B)This would lead to K+ flow out of heart cells,causing increased hyperpolarization.
C)G-protein activation and K+ channel opening would be slowed.Heart rate may remain abnormally high,especially following stress.
D)This would lead to K+ flow into heart cells,causing increased depolarization.

Question 74

The outside of a neuron is positively charged at resting potential.Why don't negative ions exit from the cell to normalize charge across the membrane?

A)The positive charge outside the cell repels negative ions.
B)There are no negative ions inside the cell.
C)All of the chloride ions are already outside the cell.
D)The negative charge inside the cell is carried by large proteins that cannot diffuse through the membrane.

Question 75

What is the basis of the typical -70mV resting potential in neurons? Rank the factors in order from most important to least important.
1.Na⁺ equilibrium potential
2.Ca⁺² equilibrium potential
3.K⁺ equilibrium potential

Question 76

The outside of a neuron is positively charged at resting potential.Why do K⁺ ions leave the cell when K⁺ channels open during an action potential?

A)The diffusion gradient is the only factor that affects ion movement.
B)K⁺ ions are actively pumped out by the sodium-potassium pump acting in reverse.
C)Voltage-gated K+ channels open when membrane potential reaches +50 mV during the depolarization phase.The diffusion gradient and electrical force cooperate to drive K+ ions out of the cell.
D)Negatively charged proteins leave the cell at the onset of the action potential.

Question 77

How do somatic neurons and autonomic neurons differ? (Check all that apply.)

A)Somatic neurons innervate the body surface,while autonomic neurons innervate internal structures.
B)Somatic neurons control skeletal muscle,while autonomic neurons control smooth and cardiac muscle.
C)Somatic neurons control exocrine glands,while autonomic neurons do not.
D)Somatic neurons control their effectors directly,while autonomic neurons use a series of neurons.
E)Somatic neurons are always excitatory,while autonomic neurons may be either excitatory or inhibitory.

Question 78

If K⁺ can exit the cell through leak channels,why don't they flow out until there are equal concentrations on both sides of the membrane?

A)K⁺ can act as an enzymatic cofactor,and most K⁺ ions are bound to cellular enzymes.
B)The leak channels allow a very slow leak that cannot keep pace with active import of K⁺ ions.
C)Chelator molecules trap K⁺ on the inside of the membrane.
D)The negative electrical potential inside the cell creates a force that holds the K⁺ ions in.