Chapter 12
The Central Nervous System
Describe the functional problems that would be experienced
by a person in which these fiber tracts have been cut: (a) lateral
spinothalamic, (b) ventral and dorsal spinocerebellar, (c) tectospinal.
Differentiate between spastic and flaccid paralysis.
How do the conditions paraplegia, hemiplegia, and quadriplegia
(a) Define cerebrovascular accident or CVA. (b) Describe its
possible causes and consequences.
(a) What factors account for brain growth aFer birth? (b) List
some structural brain changes observed with aging.
Critical Thinking
and Clinical Application
A 10-month-old infant has an enlarging head circumference
and delayed overall development. She has a bulging anterior
fontanelle and her CS± pressure is elevated. Based on these
findings, answer the following questions: (a) What are the
possible cause(s) of an enlarged head? (b) Which tests might be
helpful in obtaining information about this infant’s problem? (c)
Assuming the tests conducted showed the cerebral aqueduct to
be constricted, which ventricles or CS±-containing areas would
you expect to be enlarged? Which would likely not be visible?
Respond to the same questions based on a finding of obstructed
arachnoid villi.
Mrs. Jones has had a progressive decline in her mental capabilities
in the last five or six years. At first her family attributed her
occasional memory lapses, confusion, and agitation to grief over
her husband’s death six years earlier. When examined, Mrs. Jones
was aware of her cognitive problems and was shown to have an
IQ score approximately 30 points less than would be predicted by
her work history. A CT scan showed diffuse cerebral atrophy. ²e
physician prescribed an acetylcholinesterase inhibitor and Mrs.
Jones showed slight improvement. What is Mrs. Jones’s problem?
Why did the acetylcholinesterase inhibitor help?
Robert, a brilliant computer analyst, suffered a blow to his
anterior skull from a falling rock while mountain climbing.
Shortly thereaFer, it was obvious to his coworkers that his
behavior had undergone a dramatic change. Although previously
a smart dresser, he was now unkempt. One morning, he was
observed defecating into the wastebasket. His supervisor ordered
Robert to report to the company’s doctor immediately. Which
region of Robert’s brain was affected by the cranial blow?
Mrs. Adams is ready to deliver her first baby. Unfortunately, the
baby appears to have a myelomeningocele. Would a vaginal or
surgical (C-section) delivery be more appropriate and why?
²e medical chart of a 68-year-old man includes the following
notes: “Slight tremor of right hand at rest; stony facial expression;
difficulty in initiating movements.” (a) Based on your present
knowledge, what is the diagnosis? (b) What brain areas are most
likely involved in this man’s disorder, and what is the deficiency?
(c) How is this condition currently treated?
Cynthia, a 16-year-old girl, was rushed to the hospital aFer
taking a bad spill off the parallel bars. AFer she had a complete
neurological workup, her family was told that she would be
permanently paralyzed from the waist down. ²e neurologist
then outlined for Cynthia’s parents the importance of preventing
complications in such cases. Common complications include
urinary infection, bed sores, and muscular spasms. Using your
knowledge of neuroanatomy, explain the underlying reasons for
these complications.
All of the following descriptions refer to dorsal column–
medial lemniscal ascending pathways except one:
include the fasciculus gracilis and fasciculus cuneatus;
they include a chain of three neurons;
their connections
are diffuse and poorly localized;
they are concerned with
precise transmission of one or a few related types of sensory
Short Answer Essay Questions
Make a diagram showing the three primary (embryonic) brain
vesicles. Name each and then use clinical terminology to name
the resulting adult brain regions.
(a) What is the advantage of having a cerebrum that is highly
convoluted? (b) What term is used to indicate its grooves? Its
outward folds? (c) Which groove divides the cerebrum into two
hemispheres? (d) What divides the parietal from the frontal lobe?
²e parietal from the temporal lobe?
(a) Make a rough drawing of the lateral aspect of the leF cerebral
hemisphere. (b) You may be thinking, “But I just can’t draw!” So,
name the hemisphere involved with most people’s ability to draw.
(c) On your drawing, locate the following areas and provide the
major function of each: primary motor cortex, premotor cortex,
somatosensory association cortex, primary somatosensory
cortex, visual and auditory areas, prefrontal cortex, Wernicke’s
and Broca’s areas.
(a) What does lateralization of cortical functioning mean? (b)
Why is the term cerebral dominance a misnomer?
(a) What is the function of the basal nuclei? (b) Which basal nuclei
form the striatum? (c) Which arches over the diencephalon?
Explain how the cerebellum is physically connected to the brain
Describe the role of the cerebellum in maintaining smooth,
coordinated skeletal muscle activity.
(a) Where is the limbic system located? (b) Which structures
make up this system? (c) How is the limbic system important in
(a) Localize the reticular formation in the brain. (b) What does
RAS mean, and what is its function?
What is an aura?
How do sleep patterns, extent of sleeping time, and amount of
time spent in REM and NREM sleep change through life?
Compare and contrast short-term memory (STM) and long-term
memory (LTM) relative to storage capacity and duration of the
Define memory consolidation.
Compare and contrast declarative and procedural memory
relative to the types of things remembered and the importance of
conscious retrieval.
List four ways in which the CNS is protected.
(a) How is cerebrospinal fluid formed and drained? Describe its
pathway within and around the brain. (b) What happens if CS±
does not drain properly? Why is this consequence more harmful
in adults?
What constitutes the blood brain barrier?
A brain surgeon is about to make an incision. Name all the tissue
layers that she cuts through from the skin to the brain.
(a) Define concussion and contusion. (b) Why does severe brain
stem injury result in unconsciousness?
Describe the spinal cord, depicting its extent, its composition of
gray and white matter, and its spinal roots.
How do the types of motor activity controlled by the direct
(pyramidal) and indirect systems differ?
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