Deck 2: Structure and Function of the Nervous System

Question 1

In myelinated axons, action potentials are generated

A) at the nodes of Ranvier only.
B) along the entire length of the axons.
C) underneath the myelinated portions of the axons only.
D) only at the axon hillocks and axon terminals.

Answer 1

A

Question 2

Demyelinating diseases such as multiple sclerosis disrupt normal neural communication by

A) destroying receptors on postsynaptic cells so that neurotransmitters cannot bind normally.
B) creating lesions in the blood-brain barrier that allow toxic substances to enter the brain from the bloodstream.
C) causing deterioration of the fatty substance that normally coats and insulates axons.
D) diminishing the activity of the sodium-potassium pumps that usually maintain the resting potential of neurons.

Answer 2

C

Question 3

Which of the following cells devour and remove damaged brain cells?

A) astrocytes
B) microglia
C) oligodendrocytes
D) Schwann cells

Answer 3

B

Question 4

If you inserted a micropipette into a neuron without harming the cell, and pumped in a small quantity of calcium ions, each of which carried two positive charges, how would this affect the membrane potential?

A) The membrane potential would become depolarized relative to the resting potential.
B) The membrane potential would become hyperpolarized relative to the resting potential.
C) There would be no change because calcium does not contribute to the resting potential.
D) There would be no change because the sodium-potassium pump would remove excess calcium from the cell.

Question 5

The ease with which a cell membrane will permit ions to cross it is referred to as

A) the concentration gradient.
B) permeability.
C) the action potential.
D) conductivity.

Question 6

The Hodgkin-Huxley cycle describes how the depolarization of the membrane causes voltage-gated sodium channels to , allowing sodium ions to enter the cell. This change in sodium concentration then causes of the cell.

A) close ; fewer ; further depolarization
B) close ; fewer ; repolarization
C) open ; more ; further depolarization
D) open ; more ; repolarization

Question 7

Within a neuron, the transmission of information is usually . Between neurons, the transmission of information is usually .

A) chemical ; chemical
B) electrical ; electrical
C) electrical ; chemical
D) chemical ; electrical

Question 8

The value of the membrane potential to which an axon must be depolarized to initiate an action potential is called the potential for that neuron.

A) graded
B) resting
C) threshold
D) refractory

Question 9

At the resting state, a higher concentration of is found outside a neuron and a higher concentration of is found inside a neuron.

A) K⁺ ; Na⁺
B) Na⁺ ; K⁺
C) dopamine ; serotonin
D) serotonin ; dopamine

Question 10

The term concentration gradient refers to a difference in the

A) number of two different ion types within the neuron.
B) number of ions found on opposite sides of the cell membrane.
C) permeability of the membrane to one kind of ion compared to another.
D) permeability of the membrane at rest compared to during an action potential.

Question 11

Ouabain is a toxin that works by permanently inhibiting the activity of sodium-potassium pumps embedded in neuronal membranes. How would ouabain administration affect the resting potential of a neuron?

A) The magnitude of the resting potential would shift toward zero.
B) The resting potential would hyperpolarize toward a more negative value.
C) The resting potential would reverse to a positive, rather than a negative, value.
D) Application of ouabain would not affect the resting potential.

Question 12

Which of the following cells produce myelin in the peripheral nervous system?

A) astrocytes
B) microglia
C) oligodendrocytes
D) Schwann cells

Question 13

Two main types of projections extend from the cell body of a neuron. receive inputs from other neurons, while send information to other neurons.

A) synapses ; glia
B) axons ; dendrites
C) glia ; synapses
D) dendrites ; axons

Question 14

The , which is comprised of astrocytes, protects the brain from chemical compounds circulating in the body that might otherwise interfere with neuronal activity.

A) sodium-potassium pump
B) blood-brain barrier
C) myelin sheath
D) lipid bilayer

Question 15

The nodes of Ranvier are

A) vesicles of neurotransmitters, stored in presynaptic neurons.
B) points along axons where sodium-potassium pumps are found.
C) vesicles of calcium ions, stored in postsynaptic neurons.
D) points along axons that are not surrounded by myelin.

Question 16

The poison tetraethylammonium TEA) interferes with normal neural communication. The toxin binds to and blocks voltage-gated potassium channels in the neuron cell membrane. Which of the following best describes the effects of TEA on the action potential?

A) The depolarization phase of the action potential fails to occur.
B) The repolarization phase of the action potential is blocked.
C) The refractory period of the action potential is shortened.
D) The action potential fails to be regenerated at the nodes of Ranvier.

Question 17

In the nervous system, these cells provide structural support and insulation for neurons.

A) glia
B) dendrites
C) mitochondria
D) Purkinje cells

Question 18

If you were to insert a microelectrode through the cell membrane of a neuron, you would be able to demonstrate that

A) the region inside the cell membrane contains more positive ions than the region outside the membrane.
B) the region inside the cell membrane contains more negative ions than the region outside the membrane.
C) there is a greater concentration of potassium ions outside the cell membrane than inside the membrane.
D) there is a greater concentration of potassium ions inside the cell membrane than outside the membrane.

Question 19

The primary reason why neurons are refractory for a short period after firing action potentials, and the reason underlying the absolute refractory period, is that the

A) voltage-gated sodium channels are inactivated.
B) voltage-gated potassium channels are inactivated.
C) sodium-potassium pump has to remove sodium ions from inside the cell.
D) sodium-potassium pump has to retrieve potassium ions from outside the cell.

Question 20

The two main classes of cell in the nervous system are

A) dendrites and axons.
B) axons and neurons.
C) neurons and glial cells.
D) glial cells and dendrites.

Question 21

A gap junction is

A) the point where a neurotransmitter vesicle binds to the presynaptic membrane.
B) a connection between two sections of a G protein that plays a role in second-messenger cascades.
C) a transmembrane channel that connects the cytoplasm of two cells at an electrical synapse.
D) more likely to be found on the amino acids than on the biogenic amines.

Question 22

The two main divisions of the central nervous system are the

A) forebrain and brainstem.
B) white matter and gray matter.
C) brain and spinal cord.
D) cerebral hemispheres and cerebellum.

Question 23

Neurons in two different regions of Brodmann's cytoarchitectonic map always

A) use different types of neurotransmitters to communicate.
B) differ in cell morphology and organization.
C) lie inside different lobes of the cerebral cortex.
D) are separated by fissures in the cortex.

Question 24

The most caudal lobe of the cerebral cortex is the lobe.

A) frontal
B) temporal
C) occipital
D) parietal

Question 25

The most important function of myelin in the nervous system is to

A) form the blood-brain barrier.
B) trigger the release of neurotransmitters from axon terminals.
C) produce cerebrospinal fluid in the cerebral ventricles.
D) facilitate conduction of action potentials in axons.

Question 26

Consider the synapse shown schematically here. If neuron A causes neuron B to become hyperpolarized relative to B's resting state,

A) neuron B is more likely to fire its own action potential.
B) neuron B is less likely to release neurotransmitter molecules from its own axon terminal.
C) neuron B is more likely to absorb extracellular potassium through voltage-gated channels.
D) neuron B is less likely to absorb extracellular sodium through the sodium-potassium pump.

Question 27

The difference between gray matter and white matter is that gray matter refers to , whereas white matter refers to .

A) protruding rounded surfaces ; fissures and invaginations
B) fissures and invaginations ; protruding rounded surfaces
C) cell bodies ; axons and glial cells
D) axons and glial cells ; cell bodies

Question 28

The role of calcium ions Ca²⁺) in synaptic transmission is to

A) bind neurotransmitter molecules to the postsynaptic membrane.
B) mediate the release of neurotransmitter molecules from the presynaptic neuron.
C) repolarize the postsynaptic cell after transmission has been completed.
D) increase the activity of the sodium-potassium pumps in the presynaptic cell.

Question 29

The primary benefit that the nervous system gains from myelination is

A) generation of currents actively action potentials) rather than passively electrotonic conduction).
B) decreased membrane resistance.
C) increased resting potentials.
D) faster neural communication.

Question 30

The thick outer membrane that encloses the brain within the skull is the

A) gray matter.
B) white matter.
C) myelin sheath.
D) dura mater.

Question 31

The morphology of the brain of Albert Einstein revealed an unusual Sylvian fissure-the division that separates the lobe from the lobes.

A) occipital ; frontal and parietal
B) temporal ; frontal and parietal
C) frontal ; temporal and occipital
D) parietal ; temporal and occipital

Question 32

Which of the following is NOT a mechanism for removing a neurotransmitter from the synaptic cleft?

A) diffusion of the neurotransmitter away from the synapse
B) active reuptake of the neurotransmitter back into the presynaptic terminal
C) enzymatic breakdown of the neurotransmitter in the synaptic cleft
D) transport of the neurotransmitter by ion channels into neighboring glial cells

Question 33

All of the following are advantages of a folded cerebral cortex EXCEPT

A) the need for blood vasculature in the cortex is eliminated.
B) neural conduction time between areas is reduced.
C) neurons are brought into closer three-dimensional relationships.
D) more cortical surface can be packed into the skull.

Question 34

The term saltatory conduction refers to the fact that

A) action potentials travel faster when extracellular salt concentration is high.
B) action potentials evoked by strong stimuli travel faster than those evoked by weaker stimuli.
C) action potentials occur only at the nodes of Ranvier of axons.
D) action potentials are generated only by myelinated portions of axons.

Question 35

The effect of a particular neurotransmitter on postsynaptic neurons

A) is always either excitatory or inhibitory.
B) depends on the properties of the postsynaptic neuron.
C) may be modulated by the presence or absence of another neurotransmitter.
D) Both b and c are true.

Question 36

Gray matter is to white matter as are to .

A) gyri ; sulci
B) glial cells ; neurons
C) cell bodies ; axon tracts
D) oligodendrocytes ; Schwann cells

Question 37

Which of the following is a catecholamine?

A) gamma-aminobutyric acid GABA)
B) glutamate
C) serotonin
D) norepinephrine

Question 38

Many drugs produce their effects by facilitating or interfering with neurotransmitters at synapses. Which of the following drugs would most likely increase the effect of serotonin?

A) a drug that binds to directly coupled serotonin receptors but does not change membrane permeability
B) a drug that prevents the activity of an enzyme that breaks down serotonin molecules in the synaptic cleft
C) a drug that blocks the effect of Ca²⁺ ions
D) a drug that blocks the effect of a conditional neurotransmitter that normally facilitates the effect of serotonin

Question 39

Which of the following sequences of steps best represents the order of events that occur during synaptic transmission?

A) binding of neurotransmitter at the postsynaptic membrane -> diffusion of neurotransmitter across the synapse -> release of neurotransmitter from the presynaptic cell
B) diffusion of neurotransmitter across the synapse -> binding of neurotransmitter at the postsynaptic membrane -> release of neurotransmitter from the presynaptic cell
C) release of neurotransmitter from the presynaptic cell -> binding of neurotransmitter at the postsynaptic membrane -> diffusion of neurotransmitter across the synapse
D) release of neurotransmitter from the presynaptic cell -> diffusion of neurotransmitter across the synapse -> binding of neurotransmitter at the postsynaptic membrane

Question 40

Which of the following statements best describes the immediate consequence of neurotransmitter molecules binding to postsynaptic receptors?

A) Voltage-gated channels in the cell membrane open and permit ion flow through the membrane.
B) The activity of the sodium-potassium pumps increases.
C) Calcium absorption into the axon terminal cell is triggered.
D) Neurotransmitter-containing vesicles bind to the inside of the axon terminal membrane.

Question 41

The volume of cortex that is not sensory or motor has traditionally been termed cortex.

A) extrastriate
B) cognitive
C) association
D) equipotential

Question 42

A patient reports that she is functionally blind after a focal brain injury, even though her eyes and optic nerves are completely intact. Of the structures listed here, the most probable location for the brain injury is the

A) inferior colliculus.
B) lateral geniculate nucleus.
C) superior temporal lobe.
D) postcentral gyrus.

Question 43

The primary auditory cortex is organized using a tonotopic map, which means that there is an orderly representation of

A) loudness.
B) frequency.
C) duration.
D) spatial location.

Question 44

Cerebrospinal fluid CSF) is produced in the lateral and third ventricles by the

A) dura mater.
B) substantia nigra.
C) globus pallidus.
D) choroid plexus.

Question 45

Communication between the two hemispheres of the brain occurs mainly through the

A) basal ganglia.
B) cingulate gyrus.
C) corpus callosum.
D) limbic system.

Question 46

The temporal lobe likely bears this name because

A) it is the brain's center for temporal processing.
B) its functions are particularly susceptible to the effects of aging.
C) it lies beneath the area of the scalp where hair grays with age.
D) its neurons fire more quickly than neurons in other brain regions.

Question 47

The part of the thalamus that is most important in relaying information to the primary visual cortex is the

A) lateral geniculate nucleus.
B) superior colliculus.
C) medial geniculate nucleus.
D) inferior colliculus.

Question 48

Following a focal brain injury, a patient shows great difficulty in discriminating tones that differ in frequency. Which area of the cortex is most likely affected?

A) the superior temporal lobe
B) the inferior temporal lobe
C) the anterior parietal lobe
D) the posterior parietal lobe

Question 49

The frontal lobe is to the occipital lobe, whereas the temporal lobe is to the parietal lobe.

A) posterior ; superior
B) anterior ; inferior
C) superior ; caudal
D) inferior ; rostral

Question 50

The corpus callosum

A) permits communication between the two cerebral hemispheres.
B) is the area of the cortex in which information about touch, pain, temperature, and limb position is processed.
C) separates the temporal lobe from the frontal and parietal lobes.
D) is a fluid-filled chamber that cushions and supports the brain.

Question 51

All of the following terms refer to the same cortical region that processes visual input EXCEPT

A) striate cortex.
B) area V1.
C) Heschl's gyrus.
D) Brodmann area 17.

Question 52

As a result of a brain injury to the medial temporal lobes and neighboring subcortical structures, a patient exhibits a number of cognitive and behavioral changes. Of the options here, which is the LEAST likely to be affected?

A) memory
B) emotional processing
C) learning
D) somatosensation

Question 53

Of the following choices, the most anterior portion of the frontal lobes-the prefrontal cortex-is most critical to

A) processing information about pain, touch, and temperature.
B) executive functions.
C) the "what" visual pathway.
D) the "where" visual pathway.

Question 54

This brain structure is often called the gateway to the cortex because almost all sensory inputs synapse here before continuing to their primary cortical sensory areas.

A) hypothalamus
B) hippocampus
C) thalamus
D) amygdala

Question 55

The primary visual cortex, or V1, is located in

A) the striate cortex.
B) Brodmann area 17.
C) the calcarine fissure.
D) all of the above.

Question 56

The term cytoarchitectonics refers to

A) how cells in one brain region appear morphologically and how they are arranged with respect to each other.
B) how assemblies of neurons function together and how they communicate with neighboring ganglia.
C) how different brain regions differ in volume and how they interact to produce complex cognitive phenomena.
D) how the brains of different animals differ from each other in gross anatomy and the evolutionary bases of these differences.

Question 57

All of the structures listed here are major components of the basal ganglia EXCEPT the

A) globus pallidus.
B) amygdala.
C) caudate nucleus.
D) putamen.

Question 58

Which of the following functions is NOT mediated primarily by the hypothalamus?

A) endocrine system regulation
B) maintenance of homeostatic states in the body
C) relay of sensory information from the body to the cortex
D) hormone control

Question 59

The central sulcus is an anatomical landmark that separates the lobe from the lobe.

A) temporal ; frontal
B) frontal ; parietal
C) parietal ; occipital
D) occipital ; temporal

Question 60

The neocortex typically contains cortical layers, with typically being the input layer.

A) 10 ; layer IV
B) 10 ; layer I
C) 6 ; layer IV
D) 6 ; layer I

Question 61

The cells in the brain that guide migrating neurons to their final locations are called

A) microglia.
B) radial glia.
C) oligodendrocytes.
D) ventricular cells.

Question 62

Injury to the hypothalamus would most likely interfere with

A) hormone regulation.
B) motor control.
C) memory.
D) olfactory sensation.

Question 63

A patient has great difficulty in maintaining his posture, walking, and coordinating his movements. His brain injuries probably involve the

A) cerebellum.
B) corpus callosum.
C) superior colliculus.
D) third ventricle.

Question 64

The cell body of a neuron contains the same machinery found in most cells, including a nucleus, ribosomes, and mitochondria.

Question 65

Hyperpolarization makes the inside of a cell more positive and more likely to generate an action potential.

Question 66

Which of the following statements regarding the prenatal development of the human nervous system is correct?

A) The brain develops from ectoderm cells, whereas the spinal cord develops from mesoderm cells.
B) Ectoderm cells are the precursors of the entire nervous system.
C) Glial cells are derived from endoderm cells, whereas neurons are derived from ectoderm cells.
D) Mesoderm cells are the precursors for all parts of the human nervous system.

Question 67

The resting potential of a neuron is typically +40 to +90 millivolts mV).

Question 68

As a result of a brain injury to this diencephalic structure, a patient is experiencing disruptions in maintaining homeostasis of bodily states and endocrine control.

A) thalamus
B) hypothalamus
C)
D) hippocampus cingulate gyrus

Question 69

refers to the process of rapid cell division that occurs early in development of the nervous system.

A) Neurulation
B) Neuronal proliferation
C) Neuronal migration
D) Neural determination

Question 70

Dendrites, which are large treelike processes extending from a neuron, are said to be presynaptic.

Question 71

The dorsal portions of the gray matter in the spinal cord carry

A) motor information.
B) sensory information.
C) motor and sensory information from the dorsal surface of the body.
D) sensory and motor information to the cerebellum.

Question 72

is the idea that the columnar organization in the adult cortex is derived during development from the cells dividing in the ventricular region.

A) Topographic mapping
B) The sensory homunculus
C) The radial unit hypothesis
D) The ventricular zone hypothesis

Question 73

Action potentials are electrical signals that are conducted down the axon of a neuron.

Question 74

The ³H-thymidine labeling method is especially useful in determining when particular cells in the nervous system emerge because

A) only cells that are fully myelinated at the time of injection are radioactively labeled.
B) only glial cells absorb the marker and are radioactively labeled.
C) only cells that are fully mature at the time of injection are radioactively labeled.
D) only cells that are undergoing cell division at the time of injection are radioactively labeled.

Question 75

The brainstem includes all of the following components EXCEPT the

A) medulla.
B) midbrain.
C) hypothalamus.
D) pons.

Question 76

Parts of the brain where metabolic activity is relatively high are characterized by

A) elevated regional blood flow.
B) increased cerebrospinal fluid production.
C) a high degree of myelination.
D) greater concentrations of calcium ions.

Question 77

The term selective permeability refers to the fact that a cell membrane will allow some ions to pass through more readily than others.

Question 78

The specialized structures that comprise the midbrain control functions such as

A) hormone regulation.
B) visual reflexes.
C) memory.
D) emotional processing.

Question 79

This type of early cell line is the precursor to the cells that will compose the nervous system.

A) blastula
B) gastrula
C) endoderm
D) ectoderm

Question 80

The equilibrium potential is the membrane voltage at which there is no net flow of ions in or out.