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Chapter
2: The Nervous System
MULTIPLE CHOICE
1. Which of the following is an accurate
statement regarding neurons and glia cells?
|
a.
|
Neurons control behavior; glia cells
support the function of neurons
|
|
b.
|
Glia cells control behavior; neurons
support the function of glia cells
|
|
c.
|
Neurons are restricted to the brain;
glia cells are restricted to the periphery
|
|
d.
|
Glia cells are restricted to the
brain; neurons are restricted to the periphery
|
ANS: A PTS: 1 REF: Cells in the Nervous System
2. What is the function of neuronal dendrites?
|
a.
|
They produce the myelin sheath.
|
|
b.
|
They send neurotransmitters to other
neurons.
|
|
c.
|
They contain the neuron’s genetic
material.
|
|
d.
|
They receive information from other
neurons.
|
ANS: D PTS: 1 REF: Cells in the Nervous System
3. What is the function of a neuron’s axon?
|
a.
|
It produces the myelin sheath.
|
|
b.
|
It sends neurotransmitters to other
neurons.
|
|
c.
|
It contains the neuron’s genetic
materials.
|
|
d.
|
It receives information from other
neurons.
|
ANS: B PTS: 1 REF: Cells in the Nervous System
4. The small space between the axon terminal and
postsynaptic terminal is called the ____.
|
a.
|
soma
|
c.
|
nucleus
|
|
b.
|
synaptic cleft
|
d.
|
receptor
|
ANS: B PTS: 1 REF: Cells in the Nervous System
5. Dr. Mitchum is exploring the role of sensory
neurons (which convey sensory information to the central nervous system) in
detecting incremental changes in temperature. Which type of neuron is Dr.
Mitchum studying?
|
a.
|
afferent neuron
|
c.
|
intraneuron
|
|
b.
|
efferent neuron
|
d.
|
interneuron
|
ANS: A PTS: 1 REF: Cells in the Nervous System
TOP: Cells in the Nervous
System
6. Dr. Goulard is investigating mechanisms of
preserving the function of motor neurons (which convey motor information from
the central nervous system) in amyotrophic lateral sclerosis. Which type of
neuron is Dr. Goulard studying?
|
a.
|
afferent neuron
|
c.
|
intraneuron
|
|
b.
|
efferent neuron
|
d.
|
interneuron
|
ANS: B PTS: 1 REF: Cells in the Nervous System
TOP: Cells in the Nervous
System
7. Which cell type produces a material called myelin?
|
a.
|
neurons
|
c.
|
astrocytes
|
|
b.
|
oligodendrocytes
|
d.
|
microglial cells
|
ANS: B PTS: 1 REF: Cells of the Nervous System
8. Which cell type plays a role in forming the
blood-brain barrier?
|
a.
|
neurons
|
c.
|
astrocytes
|
|
b.
|
oligodendrocytes
|
d.
|
microglial cells
|
ANS: C PTS: 1 REF: Cells of the Nervous System
9. Which cell type removes cellular waste?
|
a.
|
neurons
|
c.
|
astrocytes
|
|
b.
|
oligodendrocytes
|
d.
|
microglial cells
|
ANS: D PTS: 1 REF: Cells of the Nervous System
Anatomical Terminology
During your Anatomy and Physiology lab, your Professor asks you to
examine a model of the human brain. Your lab partner is not familiar with the
terminology that your professor is using. Help your lab partner by telling him
where to look at the model.
10. “Examine the anterior portion of the brain.” Where do you tell
your lab partner to look?
|
a.
|
Toward the front of the brain
|
c.
|
Toward the midline of the brain
|
|
b.
|
Toward the rear of the brain
|
d.
|
Toward the side of the brain
|
ANS: A PTS: 1
REF: The Nervous System: Control
of Behavior and Physiological Functions
11. “Examine the dorsal portion of the brain.” Where do you tell your
lab partner to look?
|
a.
|
Toward the top of the brain
|
c.
|
Toward the bottom of the brain
|
|
b.
|
Toward the rear of the brain
|
d.
|
Toward the side of the brain
|
ANS: A PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
12. “Examine the posterior portion of the brain.” Where do you tell
your lab partner to look?
|
a.
|
Toward the front of the brain
|
c.
|
Toward the bottom of the brain
|
|
b.
|
Toward the rear of the brain
|
d.
|
Toward the side of the brain
|
ANS: B PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
13. “Examine the lateral portion of the brain.” Where do you tell your
lab partner to look?
|
a.
|
Toward the back of the brain
|
c.
|
Toward the midline of the brain
|
|
b.
|
Toward the bottom of the brain
|
d.
|
Toward the sides of the brain
|
ANS: D PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
14. A plane that shows brain structures as
seen from the side is referred to as a ____.
|
a.
|
coronal plane
|
c.
|
frontal plane
|
|
b.
|
sagittal plane
|
d.
|
horizontal plane
|
ANS: B PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
15. A plane that shows brain structures as seen from the front (or
frontal plane) is referred to as a ____.
|
a.
|
coronal plane
|
c.
|
transverse plane
|
|
b.
|
sagittal plane
|
d.
|
horizontal plane
|
ANS: A PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
16. A plane that shows brain structures as seen from above is referred
to as a ____.
|
a.
|
coronal plane
|
c.
|
frontal plane
|
|
b.
|
sagittal plane
|
d.
|
horizontal plane
|
ANS: D PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
17. The nervous system consists of two systems: ____.
|
a.
|
the peripheral nervous system and the
frontal nervous system
|
|
b.
|
the tangential nervous system and the
frontal nervous system
|
|
c.
|
the peripheral nervous system and the
central nervous system
|
|
d.
|
the tangential nervous system and the
central nervous system
|
ANS: C PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
18. Which nervous system delivers voluntary motor signals from the
central nervous system to muscles throughout the body and conveys sensory
information from the body to the central nervous system?
|
a.
|
sympathetic nervous system
|
c.
|
parasympathetic nervous system
|
|
b.
|
somatic nervous system
|
d.
|
autonomic nervous system
|
ANS: B PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
19. Which nervous system prepares the body for rigorous activity by
increasing heartbeat, inhibiting digestion, and opening airways?
|
a.
|
sympathetic nervous system
|
c.
|
parasympathetic nervous system
|
|
b.
|
somatic nervous system
|
d.
|
central nervous system
|
ANS: A PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
20. After encountering a ferocious dog while
walking back from your psychopharmacology lecture, your heart races. After the
dog turns in the other direction you began to relax and your heart beat slows
down. What nervous system is primarily responsible for initiating your more
relaxed state?
|
a.
|
sympathetic nervous system
|
c.
|
parasympathetic nervous system
|
|
b.
|
somatic nervous system
|
d.
|
central nervous system
|
ANS: C PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
21. Which structure is part of the forebrain?
|
a.
|
medulla
|
c.
|
thalamus
|
|
b.
|
cerebellum
|
d.
|
pons
|
ANS: C PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
22. The autonomic nervous system is controlled by the ____.
|
a.
|
medulla
|
c.
|
thalamus
|
|
b.
|
limbic system
|
d.
|
basal ganglia
|
ANS: A PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
23. Narcotics and central nervous system depressants suppress
medullary functions. Why might these drugs be fatal at high doses?
|
a.
|
May suppress breathing
|
c.
|
May increase risk of stroke
|
|
b.
|
May cause rapid heart rate
|
d.
|
May cause hyperemia
|
ANS: A PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
24. It is 5 PM and Jane is dreaming of leaving work so that she can
sink her teeth into a juicy hamburger. Which of Jane’s brain structures is most
contributing to her feeling of hunger?
|
a.
|
basal ganglia
|
c.
|
medulla
|
|
b.
|
cerebellum
|
d.
|
hypothalamus
|
ANS: D PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
25. Tania sees a dark shadow outside her window and feels frightened.
What brain structure contributes most to her feeling of fear?
|
a.
|
basal ganglia
|
c.
|
limbic system
|
|
b.
|
pons
|
d.
|
hypothalamus
|
ANS: C PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
26. The nucleus accumbens is also called the brain’s ____ center.
|
a.
|
reward
|
c.
|
motor control
|
|
b.
|
command
|
d.
|
perception
|
ANS: A PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
27. Which lobe of the cerebral cortex processes auditory information
and supports language comprehension and production?
|
a.
|
occipital lobe
|
c.
|
parietal lobe
|
|
b.
|
temporal lobe
|
d.
|
frontal lobe
|
ANS: B PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
28. Which lobe of the cerebral cortex is primarily responsible for
processing visual information?
|
a.
|
occipital lobe
|
c.
|
parietal lobe
|
|
b.
|
temporal lobe
|
d.
|
frontal lobe
|
ANS: A PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
29. Which lobe of the cerebral cortex processes touch information from
the body?
|
a.
|
occipital lobe
|
c.
|
parietal lobe
|
|
b.
|
temporal lobe
|
d.
|
frontal lobe
|
ANS: C PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
30. Which lobe of the cerebral cortex supports decision making and
movement?
|
a.
|
occipital lobe
|
c.
|
parietal lobe
|
|
b.
|
temporal lobe
|
d.
|
frontal lobe
|
ANS: D PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
31. Which tract crosses from one hemisphere of the brain to the
opposite side of the body, sending motor information to the limbs, hands, and
feet?
|
a.
|
medial corticospinal tract
|
c.
|
dorsal spinocerebellar tract
|
|
b.
|
lateral corticospinal tract
|
d.
|
cuneocerebellar tract
|
ANS: B PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
32. Which brain structures act to stabilize voluntary movements?
|
a.
|
hippocampus, thalamus, and amygdala
|
|
b.
|
hippocampus, thalamus, and substantia
nigra
|
|
c.
|
basal ganglia, thalamus, and
substantia nigra
|
|
d.
|
basal ganglia, thalamus, and amygdala
|
ANS: C PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
33. The first drugs to treat schizophrenia,
called antipsychotic drugs, caused Parkinson-like symptoms. Why?
|
a.
|
Antipsychotic drugs disrupt neurons in
the substantia nigra.
|
|
b.
|
Antipsychotic drugs damage neurons in
the thalamus.
|
|
c.
|
Antipsychotic drugs cause
demyelination of the corticospinal tracts.
|
|
d.
|
Antipsychotic drugs increase the
number of dopamine receptors.
|
ANS: A PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
34. Megan is walking to the student center, lost in deep thought, when
her friend Roman runs up behind her, tapping her on the shoulder. Megan,
startled by Roman, jumps and gasps for air. Which brain structure is
responsible for Megan’s startle reflex?
|
a.
|
pons
|
c.
|
basal ganglia
|
|
b.
|
cerebellum
|
d.
|
hippocampus
|
ANS: A PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
35. Working memory is part of your ____.
|
a.
|
short-term memory
|
c.
|
reference memory
|
|
b.
|
sensory memory
|
d.
|
long-term memory
|
ANS: A PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
36. Second-grade teacher Ms. Frascella calls upon her star pupil,
Jeremy, to recite the capitals of all 50 states. Which type of memory will
Jeremy use to recall this information?
|
a.
|
short-term memory
|
c.
|
working memory
|
|
b.
|
sensory memory
|
d.
|
long-term memory
|
ANS: D PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
37. Mabel was recently diagnosed with Alzheimer’s disease. She is
beginning to show significant impairment of her long-term memory. Damage to
which brain structure likely caused this impairment?
|
a.
|
amygdala
|
c.
|
hippocampus
|
|
b.
|
cerebellum
|
d.
|
thalamus
|
ANS: C PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
38. After a recent bicycle accident, 11 year old Todd cannot do things
that were once routine, such as such as riding a bike. Damage to which of
Todd’s brain structure disrupted Todd’s procedural memory required for riding
his bike?
|
a.
|
basal ganglia
|
c.
|
pons
|
|
b.
|
amygdala
|
d.
|
hypothalamus
|
ANS: A PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
39. Activity within which brain structures
support arousal in the cerebral cortex, thus indirectly aiding in memory
formation?
|
a.
|
dentate gyrus
|
c.
|
limbic system
|
|
b.
|
reticular formation
|
d.
|
pyramidal system
|
ANS: B PTS: 1
REF: The Nervous System:
Control of Behavior and Physiological Functions
40. Ted is studying for his neuropsychology exam. How is cerebral
blood flow to Ted’s prefrontal cortex likely to respond to his studying?
|
a.
|
Blood flow will remain constant.
|
|
b.
|
Blood flow will decrease.
|
|
c.
|
Blood flow will increase.
|
|
d.
|
Blood flow will show variable changes.
|
ANS: C PTS: 1 REF: Blood Flow in the Brain
41. What is the role of nitric oxide in the brain?
|
a.
|
increases blood flow and increases
oxygen levels
|
|
b.
|
decreases blood flow, but increases
oxygen levels
|
|
c.
|
increases blood flow, but decreases
oxygen levels
|
|
d.
|
decreases blood flow and decreases
oxygen levels
|
ANS: A PTS: 1 REF: Blood Flow in the Brain
42. What term is used to describe a decrease in cerebral blood flow
that may potentially cause cell death if severe or persistent enough?
|
a.
|
infarct
|
c.
|
ischemia
|
|
b.
|
excitotoxicity
|
d.
|
hyperemia
|
ANS: C PTS: 1 REF: Blood Flow in the Brain
43. Peter’s physician, Dr. Ma, is concerned that he suffered a stroke
after he complains of loss of feeling in his left arm. Which diagnostic test
will help Dr. Ma visualize Peter’s circulatory system to determine if he
suffered a stroke?
|
a.
|
CAT scan
|
c.
|
fMRI
|
|
b.
|
PET scan
|
d.
|
angiogram
|
ANS: D PTS: 1 REF: Blood Flow in the Brain
44. The brain is supplied with blood through two major arteries: ____.
|
a.
|
the dorsal scapular artery and the vertebral artery
|
|
b.
|
the dorsal scapular artery and the
carotid artery
|
|
c.
|
the carotid artery and the femoral
artery
|
|
d.
|
the carotid artery and the vertebral
artery
|
ANS: D PTS: 1 REF: Blood Flow in the Brain
45. The brain contains cerebrospinal fluid–filled cavities called
____.
|
a.
|
periaqueductal gray areas
|
c.
|
ventricles
|
|
b.
|
arterioles
|
d.
|
meninges
|
ANS: C PTS: 1 REF: Cerebrospinal Fluid
46. Which is a function of cerebrospinal fluid?
|
a.
|
It transports oxygen.
|
c.
|
It serves as a protective cushion.
|
|
b.
|
It produces immune cells.
|
d.
|
It clears myelin.
|
ANS: C PTS: 1 REF: Cerebrospinal Fluid
47. What is the function of the blood-brain barrier?
|
a.
|
It provides protective cushion.
|
|
b.
|
It allows substances to easily access
the brain.
|
|
c.
|
It prevents harmful substances from
entering brain.
|
|
d.
|
It converts carbon dioxide into
oxygen.
|
ANS: C PTS: 1 REF: The Blood–Brain Barrier
48. Dr. Pearson wants to design a drug that easily passes through the
blood-brain barrier. As an expert in psychopharmacology, you suggest that Dr.
Pearson ensure that the chemical structure that he designs is small, as well as
____.
|
a.
|
lipid soluble and uncharged
|
c.
|
lipid soluble and charged
|
|
b.
|
water soluble and uncharged
|
d.
|
water soluble and charged
|
ANS: A PTS: 1 REF: The Blood–Brain Barrier
49. Drug X passes through the blood-brain barrier via active
transport. What does this mean?
|
a.
|
Drug X diffuses through the
blood-brain barrier.
|
|
b.
|
Drug X uses osmosis to pass through
the blood-brain barrier.
|
|
c.
|
Drug X directly attaches to neurons to
pass through the blood-brain barrier.
|
|
d.
|
Drug X uses channels to pass through
the blood-brain barrier.
|
ANS: D PTS: 1 REF: The Blood–Brain Barrier
50. The primary features of the central nervous system are produced
during the ___ trimester of pregnancy.
|
a.
|
first
|
c.
|
third
|
|
b.
|
second
|
d.
|
fourth
|
ANS: A PTS: 1
REF: The Nervous System:
Rapid Development After Fertilization
51. Expecting mom Giselle reads about her pregnancy on the website Mommy-and-Me.
She learns that her unborn baby developed noticeable ridges and grooves
(termed gyri and sulci) within the cerebral cortex. During which gestational
period do these gyri and sulci first become most apparent?
|
a.
|
12 to 18 weeks into a pregnancy
|
c.
|
24 to 30 weeks into a pregnancy
|
|
b.
|
18 to 24 weeks into a pregnancy
|
d.
|
30 to 36 weeks into a pregnancy
|
ANS: C PTS: 1
REF: The Nervous System:
Rapid Development After Fertilization
52. Which is the correct order of events during
brain cell development?
i. synaptic rearrangement
ii. differentiation
iii. migration
iv. synaptogenesis
v. apoptosis
vi. proliferation
|
a.
|
ii, vi, iii, v, i, iv
|
c.
|
ii, iii, vi, iv, i, v
|
|
b.
|
vi, iii, ii, iv, v, i
|
d.
|
vi, ii, iii, iv, i, v
|
ANS: B PTS: 1
REF: The Nervous System:
Rapid Development After Fertilization
53. The blueprints for a neuron and its functions reside within the
____.
|
a.
|
axon terminals
|
c.
|
mitochondria
|
|
b.
|
dendrites
|
d.
|
nucleus
|
ANS: D PTS: 1
REF: Genes and the
Development and Physiological Processes of Cells
54. How many chromosomes does a child inherit from each parent?
|
a.
|
16
|
c.
|
43
|
|
b.
|
23
|
d.
|
46
|
ANS: B PTS: 1
REF: Genes and the
Development and Physiological Processes of Cells
55. Each chromosome contains a strand of ____.
|
a.
|
ribonucleic acid
|
c.
|
transcription factors
|
|
b.
|
deoxyribonucleic acid
|
d.
|
ribosomes
|
ANS: B PTS: 1
REF: Genes and the
Development and Physiological Processes of Cells
56. Everyone has genes for eye color, but variations in the coding
sequence of these genes allow for a variety of eye colors in a population. The
term to best describe this variation in coding sequences is ____.
|
a.
|
independent assortment
|
c.
|
heritability
|
|
b.
|
allelic segregation
|
d.
|
polymorphism
|
ANS: D PTS: 1
REF: Genes and the
Development and Physiological Processes of Cells
57. The activation of genes leads to the synthesis and release of
genetic information, a process referred to as gene ____.
|
a.
|
transcription
|
c.
|
transference
|
|
b.
|
encoding
|
d.
|
translation
|
ANS: A PTS: 1
REF: Genes and the
Development and Physiological Processes of Cells
58. The type of RNA used to trigger protein
synthesis is called ____ RNA.
|
a.
|
transfer
|
c.
|
ribosomal
|
|
b.
|
nucleic
|
d.
|
messenger
|
ANS: D PTS: 1
REF: Genes and the
Development and Physiological Processes of Cells
59. Dr. Leighton is performing a literature search to learn more about
a process termed gliosis. What is she likely to find out?
|
a.
|
Astrocytes facilitate axonal regrowth
after injury.
|
|
b.
|
Astrocytes hinder axonal regrowth
after injury.
|
|
c.
|
Astrocytes produce new myelin for
injured axons.
|
|
d.
|
Astrocytes strip injured axons of old
myelin.
|
ANS: B PTS: 1 REF: Glial Scars and Recovery from Brain Injury
60. Dr. Ambroise is developing a drug to help promote axonal
regeneration following brain injury. What might be an effective mechanism of
action for Dr. Ambroise’s drug?
|
a.
|
Inhibit BDNF production.
|
c.
|
Break down proteoglycans.
|
|
b.
|
Block uptake of neurotrophin-3.
|
d.
|
Increase production of semaphorin 3.
|
ANS: C PTS: 1 REF: Glial Scars and Recovery from Brain Injury
ESSAY
1. Draw a diagram of a neuron, identifying its
major structures. Write a brief description of the role of each structure in
facilitating neuronal communication. Include in your answer a discussion of the
synapse and how it bridges interneuronal communication.
ANS:
Note: The myelin sheath is not actually a neuronal structure, but
is part of the oligodendrocyte’s membrane (one of the three glial cell types)
which ensheaths the neuron’s axon.
Neurons have four major components: a soma, dendrites, axon, and
axon terminal. The soma is the body of the neuron. It also contains the
nucleus, which holds DNA. Overall, components within the soma support a
neuron’s basic physiological processes. Generally, a neuron has many dendrites
that branch off from the soma. The dendrites of a neuron receive information
from other neurons. Small stems called dendritic spines grow along the
length of dendritic branches. The membranes of dendrites and dendritic spines
contain proteins called receptors that neurotransmitters can activate.
When activated, receptors cause changes in the functioning of the neuron. The
overall coverage of dendrites for a neuron is called the receptive zone;
the more dendrites a neuron has, the more input it can receive from other
neurons. Axons send neurotransmitters to other neurons. Most neurons have only
one axon, which branches from the soma, usually opposite from the dendrites. An
axon begins at a part of the soma called the axon hillock and ends with
multiple branches containing axon terminals. These branches are called axon
collaterals. An axon terminal contains and releases neurotransmitters at a
part of a dendrite called a postsynaptic terminal. The postsynaptic
terminal contains receptors for neurotransmitters. The small space between the
axon terminal and postsynaptic terminal is called the synaptic cleft.
The term synapse refers to the components that comprise this connection, and
these include the axon terminal, postsynaptic terminal, and the synaptic cleft.
PTS: 1 REF: Cells in the Nervous System
2. Describe what is meant by the term glial
scar. What roadblocks to recovery from traumatic brain injury does the
glial scar present? In addition, discuss current experimental therapeutic
strategies for combating promoting axonal regeneration after brain injury.
ANS:
An important challenge in brain injury recovery consists of a
natural response to injury called a glial scar or gliosis (Silver
& Miller, 2004). A glial scar consists of reactive astrocytes —that is,
astrocytes that swell in response to injury. The resulting glial scar from
traumatic brain injury segregates damaged tissue from healthy tissue. The
action serves to repair the blood –brain barrier. In doing so, however, glial
scars prevent neurons in damaged tissue from regaining connections to other
structures in the nervous system.
Regaining
connectivity after injury involves the sprouting of severed axons. Because of
the barrier created, the glial scars caused regenerating axon terminals to
divert from the damaged tissue. These conditions result in misaligned patterns
of growth, including retractions into balls called dystrophic end bulbs.
Astrocytes in
glial scars prevent axon growth through an inhibitory extracellular matrix. The
inhibitory extracellular matrix consists of chemicals that inhibit axon growth,
including proteoglycans, secreted protein semaphorin 3, and ephrin-B2. Each
molecule prevents the growth or penetration of axons into damaged tissue
(Silver & Miller, 2004).
Experimental
treatments for traumatic brain injury recovery focus on ways to improve axon
regeneration into damaged brain areas. One approach uses the enzyme
chondroitinase to break down proteoglycans. Related approaches seek to reduce
other inhibitory components in the inhibitory extracellular matrix.
Other treatments focus
on improving the availability of growth material for axons. These strategies
often involve neural growth factors, such as neuroptrophin-3 and brain-derived
neural growth factor. The delivery of neural growth factors promotes the growth
of axons into damaged tissue.
Finally,
researchers have combined both of the preceding strategies to reduce inhibitory
extracellular matrix components while promoting the growth of axons. For
example,Tropea and colleagues (2003) assessed the effects of each approach on
damaged retinal neurons that terminate in the superior colliculus. The
application of either chondroitinase or BDNF promoted the regrowth of these
neurons into the superior colliculus.Yet far greater neuronal growth was
demonstrated by using both chrondroitinase and BDNF.
PTS: 1 REF: Glial Scars and Recovery from Brain Injury
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