ASIPP Neuroanatomy & Function Questions Flashcards

Question 1

Q

Cognitive and contextual aspects of the perceptual
dimensions of pain appear to be processed in:
A. The VPL region of the thalamus
B. The periventrivcular grey region
C. The inferotemporal and frontal cortical regions
D. The hypothalamus
E. None of the above

Answer

A

Answer: C

Source: Giordano J, Board Review 2003

Question 2

Q

207. The reversible cholinesterase inhibitor indicated in the
treatment of Alzheimer’s disease is
A. Tacrine
B. Edrophonium
C. Neostigmine
D. Pyridostigmine
E. Ambenonium

Answer

A

Answer: A
Explanation:
Reference: Katzung, p 1040.
Patients with Alzheimer’s disease present with progressive
impairment of memory and cognitive functions such as a
lack of attention, disturbed language function, and an
inability to complete common tasks. Although the exact
defect in the central nervous system (CNS) has not been
elucidated, evidence suggests that a reduction in
cholinergic nerve function is largely responsible for the
symptoms.
Tacrine has been found to be somewhat effective in
patients with mild-to-moderate symptoms of this disease
for improvement of cognitive functions. The drug is
primarily a reversible cholinesterase inhibitor that
increases the concentration of functional ACh in the brain.
However, the pharmacology of tacrine is complex; the
drug also acts as a muscarinic receptor modulator in that
it has partial agonistic activity, as well as weak antagonistic
activity on muscarinic receptors in the CNS. In addition,
tacrine appears to enhance the release of ACh from
cholinergic nerves, and it may alter the concentrations of
other neurotransmitters such as dopamine and NE.
Of all of the reversible cholinesterase inhibitors, only
tacrine and physostigmine cross the blood-brain barrier in
suffi cient amounts to make these compounds useful for
disorders involving the CNS. Physostigmine has been
tried as a therapy for Alzheimer’s disease; however, it is
more commonly used to antagonize the effects of toxic
concentrations of drugs with antimuscarinic properties,
including atropine, antihistamines, phenothiazines, and
tricyclic antidepressants. Neostigmine, pyridostigmine,
and ambenonium are used maily in the treatment of
myasthenia gravis; edrophonium is useful for the
diagnosis of this muscular disease.
Source: Stern - 2004

Question 3

Q

Regeneration of axons:
A. Occurs in the segment distal to the damage
B. Is independent of the survival of the perikaryon
C. Includes a decrease in the volume of the perikaryon
D. Is dependent on proliferation of Schwann cells
E. Is initiated with an increase in production of Nissl substance

Answer

A

Answer: D
Explanation:
(Junqueira, 9/e, pp 176-180. Kandel, 4/e, p 1108-1109.)
Regeneration depends on the proliferation of Schwann
cells, which guide sprouting axons from the proximal
segment toward the target organ. This process is referred
to as Wallerian regeneration. Axonal regeneration occurs in neurons if the perikarya survive following damage. The
segment distal to the wound, including the myelin, is
phagocytosed and removed by macrophages. The proximal
segment is capable of regeneration because it remains in
continuity with the perikaryon. Chromatolysis is the fi rst
step in the regeneration process in which there is
breakdown of the Nissl substance, swelling of the
perikaryon, and migration of the nucleus peripherally
Degeneration of perikarya and neuronal processes occurs
when there is extensive neuronal damage. Transneuronal
degeneration occurs only when there are synapses with a
single damaged neuron. In the presence of inputs from
multiple neurons, transneuronal degeneration does not
occur.
Source: Klein RM and McKenzie JC 2002.

Question 4

Q

The alpha rhythm appearing on an electroencephalogram
has which of the following characteristics?
A. It produces 20 to 30 waves per second
B. It disappears when a patient’s eyes open
C. It is replaced by slower, larger waves during REM sleep
D. It represents activity that is most pronounced in the
frontal region of the brain
E. It is associated with deep sleep

Answer

A

Answer: B
Explanation:
(Guyton, pp 691-692.) In a totally relaxed adult with eyes
closed, the major component of the electroencephalogram
(EEG) will be a regular pattern of 8 to 12 waves per
second, called the alpha rhythm. The alpha rhythm
disappears when the eyes are opened. It is most prominent
in the parieto-occipital region. In deep sleep, the alpha
rhythm is replaced by larger, slower waves called delta
waves. In REM sleep, the EEG will show fast, irregular
activity.

Question 5

Q

The receptors responsible for measuring the intensity of
a steady pressure on the skin surface are:
A. Pacinian corpuscle
B. Ruffi ni ending
C. Merkel’s disk
D. Meissner’s corpuscle
E. Krause ending

Answer

A

Answer: B
Explanation:
(Rhoades, pp 69-70.)
B. The Ruffi ni ending is a tonic receptor that produces a
train of action potentials proportional to the intensity of
pressure applied to the skin.
A. The Pacinian corpuscle is a very rapidly adapting
receptor that fi res once or twice in response to skin
deformation.
It can produce a continuous train of action potentials if
the stimulus is repetitively applied and withdrawn.
Therefore, the Pacinian corpuscle is used to encode
vibration.

Question 6

Q

211. Which of the following nerve fi bers is not myelinated?
A. A alpha fi bers:
B. A delta fi bers
C. A gamma fi bers
D. B fi bers
E. C fi bers

Answer

A

Answer: E

Source: Day MR, Board Review 2004

Question 7

Q

212. Mechanical nociception appears to be predominantly
modulated by:
A. The raphe-spinal system
B. The ceruleo-spinal system
C. The GABAergic system
D. All of the above
E. None of the above

Answer

A

Answer: B

Source: Giordano J, Board Review 2003

Question 8

Q

Rubbing or patting a painful area can often reduce the
sensations of pain.This is due, at least in part, to:
A. High-threshold C-fi ber overload
B. Depletion of Substance-P within primary nocisponsive
afferents
C. Stimulation of the dorsal columnar/medial lemniscal
pathway
D. Provocation of a vasoconstrictive response to reduce local
hyperemia
E. None of the above

Answer

A

Answer: C

Source: Giordano J, Board Review 2003

Question 9

Q

The nodes of Ranvier:
A. Occur only in the CNS
B. Contain few Na+-gated channels
C. Represent the midpoints of myelination segments
D. Are completely covered by myelin
E. Increase the effi ciency of nerve conduction

Answer

A

Answer: E
Explanation:
(Junqueira, 9/e, pp 170, 171,174. Kandel, 4fe, pp21-22,
148, 160.)
B. Most of the Na+ -gated channels are located in the bare
areas.
Therefore, spread of depolarization from the nodal
region along the axon occurs until it reaches the next node.
This is often described as a series of jumps from node to
node, or saltatory conduction.
C. The nodes of Ranvier represent the space between
adjacent units of myelination.
D. This area is bare in the CNS, whereas in the PNS the
axons in the nodes are partially covered by the cytoplasmic
tongues of adjacent Schwann cells.
E. The nodes of Ranvier increase the effi ciency of nodal
conduction because of restriction of energy-dependent
Na+ infl ux to the node.
Source: Klein RM and McKenzie JC 2002.

Question 10

Q

215. Properties of pain stimulus modality and anatomic
localization are primarily conveyed along which afferent
pathway?
A. Neospinothalamic tract
B. Paleospinothalamic tract
C. Medial lemniscal tract
D. None of the above
E. All of the above

Answer

A

Answer: A

Source: Giordano J, Board Review 2003

Question 11

Q

The cells responsible for the entry of human
immunodefi ciency virus (HIV) into the CNS are
A. Microglial macrophages
B. Astrocytes (astroglia)
C. Oligodendrocytes (oligodendroglia)
D. Endothelial cells
E. Schwann cells

Answer

A

Answer: A
Explanation:
(Kandel, 4/e, p 20. Braunwald, 15/e, pp 1873, 1890-1891.)
Microglia are the macrophages of the brain. They become
infected with HIV and carry the virus into the CNS. The
virus remains latent until a stimulus activates viral
production. These cells are the most conspicuous elements
of HIV-induced CNS pathology. Infection, proliferation,
and fusion of microglia/macrophages appear to be
involved in the development of giant cell encephalitis of
acquired immune defi ciency syndrome (AIDS) and other
pathologies associated with neuronal damage in AIDS
dementia. The CNS effects of AIDS are extensive as
indicated by the fact that 90% of AIDS patients show
abnormalities in the cerebrospinal fl uid (CSF), even in
asymptomatic stages of the disease.
Source: Klein RM and McKenzie JC 2002.

Question 12

Q

Discriminatory localization and intensity of pain appear
to be primarily processed in which supratentorial area?
A. Hypothalamus
B. VPL thalamus
C. Reticular formation
D. Primary somesthetic cortex
E. All of the above

Answer

A

Answer: D

Source: Giordano J, Board Review 2003

Question 13

Q

Activation of transducin by light activates an enzyme
which
A. Hydrolyzes cGMP
B. Increases the dark current
C. Activates adenyl cyclase
D. Releases calcium from intracellular stores
E. Depolarizes the membrane

Answer

A

Answer: A
Explanation:
(Rhoades, pp 73-76.) Transducin is the G protein that
mediates the response to light by rods and cones in the eye. When transducin is activated, it activates an enzyme that hydrolyzes cyclic GMP (cGMP). In the dark, cGMP binds
to Na+ channels, keeping them open. The fl ow of Na+
through these channels keeps the rods and cones
depolarized. The activation of transducin by light and the
subsequent hydrolysis of cGMP cause the Na+ channels to
close and the membrane to hyperpolarize.
Hyperpolarization of the membrane prevents the release
of an inhibitory transmitter by the rods and cones, which
ultimately results in stimulation of optic nerve fi bers and
the awareness of a visual image.

Question 14

Q

Which one of the following hypothalamic nuclei is
responsible for the detection of the core body
A. The lateral hypothalamus
B. The arcuate nucleus
C. The posterior nucleus
D. The paraventricular nucleus
E. The anterior hypothalamus

Answer

A

Answer: E
Explanation:
(Guyton, pp 826-830.) The hypothalamus regulates body
temperature. Core body temperature, the temperature of
the deep tissues of the body, is detected bythermoreceptors
located within the preoptic area and the anterior
hypothalamic nuclei. The preoptic area also contains
neurons responsible for initiating refl exes, such as
vasodilation and sweating, which are designed to reduce
body temperature. Heat -producing refl exes, such as
shivering, and head maintenance refl exes, such as
vasoconstriction, are initiated by neurons located within
the posterior hypothalamus.

Question 15

Q

When an axon is cut, rapid local degeneration of the
axon and myelin sheath occur, as well as changes in the
cell body that affect synapses with other neurons. This
pattern of degeneration is caused by
A. Gliosis
B. Axonal transport
C. Phagocytosis
D. Excitatory neurotransmitters
E. Depolarization

Answer

A

Answer: B
Explanation:
(Kandel, pp 730-735.)
When the axon is cut, the axon and synaptic terminals
are deprived of essential metabolic connections with the
cell body. With axonal transport in both directions, there is
a rapid local degeneration of the axon and myelin sheath,
with the cell body also being affected.
Synapses mediate both electric signals and nutritive
interactions between neurons. Thus, changes occur in the
cell body (retrograde changes) and also in subsequent
neurons that receive synapses from the damaged neurons.
Macrophages from the general circulation enter the
trauma area and phagocytose axonal debris, and glial
cells (astrocytes and microglia) proliferate to assist in the
process. This proliferation of fi brous astrocytes forms a
glial scar around the trauma area, which can then block
the course of regenerating axons and the reformation of
central connections.
The behavioral effects of nerve lesions are peculiar to
the location of the lesion in the brain and the nerve cell
connections, so the same type of injury will have different
behavioral effects depending on its location
Source: Ebert 2004

Question 16

Q

What is the principal role of the descending serotonergic
system in pain processing?
A. Activation of polysynaptic interneuronal systems within
the spinal analgesic neuraxis
B. Direct inhibition of primary and second-order afferent
fi bers within the dorsal horn of the spinal cord
C. Both of the above
D. None of the above

Answer

A

Answer: C

Source: Giordano J, Board Review 2003

Question 17

Q

As a general practice
A. Opiate maintenance dosing should be discontinued
prior to trial of SCS
B. Antibiotics prophylaxis should be delivered when implanting
devices
C. Patients should be considered for neurostimulation
without a preoperative psychological assessment
D. Intrathecal drug delivery should be initiated with ziconotide
as a primary infusion
E. Trial of patients for chronic neuromodulation should not
be done by the individual who will maintain the device

Answer

A

Answer: B

Source: Feler C, Board Review 2005

Question 18

Q

In skeletal muscle contraction, the “powerstroke” is
initiated by
A. The initial binding of ATP to the myosin heads
B. Release of Pi from the myosin heads
C. Detachment of the myosin head from the actin
D. Phosphorylation of the myosin light chains
E. Release of ADP and subsequent addition of an ATP molecule

Answer

A

Answer: B
Explanation:
(Alberts, 3/e, pp 851-853. Junqueira, 9/e, pp 185-190.) The
“powerstroke” is initiated by the release of Pi from the
myosin heads, leading to the tight binding of actin and
myosin. The tight binding induces a conformational
change in the myosin head. The myosin head subsequently
pulls against the actin fi lament to cause the “powerstroke”
of the myosin head walking along the actin fi lament. This
walking process is unidirectional and is based on the
polarity of the actin fi lament (i.e., walking occurs from the
minus to the plus end of the actin fi lament). The cycle of
ATP-actin-myosin interactions during contraction begins
with the resting state. In the quiescent period,ATP binds to
myosin heads; however, hydrolysis occurs slowly and only
allows the weak binding of myosin heads to the actin
fi laments. Tight binding occurs only when Pi is released
from myosin heads, leading to the “powerstroke.”
Recycling occurs through the release of ADP and the
subsequent addition of an ATP molecule and detachment
of the myosin head from actin. Rigor results from the lack
of ATP because one ATP molecule is required for each
myosin molecule present in the muscle. Rigor mortis
occurs from the total absence of ATP.
Myosin is composed of two coiled heavy chains and four
light chains.
It may be separated into heavy and light meromyosin by
enzymatic treatment. Heavy meromyosin has two
segments: S1 (the globular head region) and S2. The S1
subfragment includes the light chains that are associated
with the globular head regions. This region is signifi cant
because it is the site of the actin binding that activates
ATPase activity. S2 is a dimeric population of the myosin
molecule that connects the two S1 segments to the coiled
light meromyosin subunit. The P light chain is one of the
two light
chains associated with the globular heads and is
phosphorylated by myosin light chain kinase. In skeletal
muscle, phosphorylation of the light chain is not required
for binding to actin.
Source: Klein RM and McKenzie JC 2002.

Question 19

Q

224.The striatum is formed by all of the following structures
EXCEPT the
A. Caudate nucleus
B. Globus pallidus
C. Olfactory tubercles
D. Nucleus accumbens
E. Substantia innominata

Answer

A

Answer: B
Explanation:
The striatum is the main receiving station for the basal
ganglia. It receives massive projections from all areas of
the cerebral cortex and from certain thalamic nuclei, the
substantia nigra, and other brain stem nuclei. The caudate
nucleus and the putamen are the largest of the nuclei
composing the striatum.The ventral striatum consists of
the ventral portion of the caudate nucleus, the putamen,
the deep layers of the olfactory tubercle, the nucleus
accumbens, and the substantia innominata. Although the
nucleus accumbens and the substantia innominata are
frequently referred to as parts of the olfactory system, they
play an important functional role in the basal ganglia.
(Afi fi and Bergman, 275-294)
Source: Neurology Examination and Board Review By
Nizar Souayah, MD and Sami Khella, MD

Question 20

Q

225.The ascending noradrenergic pathway can engage
sympathetic nervous system function
A. Only through indirect activation of preganglionic sympathetic
neurons
B. Only by direct activation of sensory associative areas in
the S-II somatosensory cortex
C. Via inhibition of the insular-anterior cingulate pathway
D. Only by engaging the thalamic intralaminar nucleus
E. By engagement of amygdalar, insular and hypothalamic
paraventricular substrates

Answer

A

Answer: E
Explanation:
Reference:
Bonica’s Management of Pain, 3rd Ed: Ch4. Spinal
mechanisms and modulation.The ascending noradrenergic
pathway is activated via input from the paleo-spinal
thalamic tract. Ascending noradrenergic fi bers from the
reticolumagnocellular group (RMC), together with PSTT
fi bers project to the parabrachial nucleus to engage the
amygdala, insula, cingulate and ultimately, hypothalamic
paraventricular nucleus to evoke sympathetic nervous
system activity. As well, the intra-laminar nucleus of the
thalamus can be activated by both NEneurons of the RMC
and the PSTT to engage hypothalamic-sympathetic
activation. Thus, multiple pathways can be activated by the
ascending NE tracts to act singularly or in concert through
the hypothalamus to engage sympathetic neural output.
Source: Giordano J, Board Review 2005

Question 21

Q

Which of the following is (are) true?
A. Neurostimulation is appropriate in patients with PVD
B. Neurostimulation is not appropriate in patients with
angina
C. Neurostimualtion is useful in all patients with low back
pain.
D. All of the above.
E. Two of the above

Answer

A

Answer: E

Source: Feler C, Board Review 2005

Question 22

Q

Neuromodulation should be considered in patients who
have no other remaining therapeutic opportunities.
A. If they have a life expectancy of greater than one
month.
B. If the pain is in the back, not the extremity
C. If the pain is in the leg but not the back.
D. If the pathophysiology is appropriate for the therapy.
E. If the patient’s insurance will cover the procedure

Answer

A

Answer: D

Source: Feler C, Board Review 2005

Question 23

Q

Contrasting neurostimulation with intraspinal drug
delivery:
A. Neurostimulation is superior in the treatment of neuropathic
pain phenomenon.
B. Intraspinal drug delivery has a higher rate of signifi cant
complications
C. Intraspsinal drug delivery is superior in the treatment
of nociceptive pain phenomenon
D. All of the above.

Answer

A

Answer: D

Source: Feler C, Board Review 2005

Question 24

Q

The EKG of a patient who is receiving digitalis in the
therapeutic dose range would be likely to show
A. Prolongation of the QT interval
B. Prolongation of the PR interval
C. Symmetric peaking of the T wave
D. Widening of the QRS complex
E. Elevation of the ST segment

Answer

A

Answer: B
Explanation:
Reference: Hardman, pp 813-814.
The usual electro cardiographic pattern of a patient
receiving therapeutic doses of digitalis includes an
increase in the PR interval, depression and sagging of the
ST segment, and occasional biphasia or inversion of the T
wave. Symmetrically peaked T waves are associated with
hyperkalemia or ischemia in most cases. Shortening of the
QT interval, rather than prolongation, is characteristic of
digitalis treatment.
Source: Stern - 2004

Question 25

Q

230. Failed back surgery syndrome patients should be
considered for SCS:
A. If that is their diagnosis
B. If they hurt in their back
C. If they hurt in their leg
D. If they have neuropathic pain
E. If they have segmental instability

Answer

A

Answer: D

Source: Feler C, Board Review 2005

Question 26

Q

Lissauer’s tract is:
A. Composed of A-delta and C-fi bers which are ascending
and descending in the superfi cial apex of the dorsal
horn prior to synapsing with dorsal horn interneurons.
B. The lateral ascending spinal tract which connects dorsal
horn interneurons to supraspinal centers.
C. The posterior descending tract which connects inhibitory
supraspinal centers to dorsal horn neurons
D. The tract which transmits pain signals from one side of
the spinal cord to the other
E. Connects post-ganglionic sympathetic fi bers to the spinal nerve.

Answer

A

Answer: A
Explanation:
Reference:
Bonica’s Management of Pain, Third Edition, Chapter 3,
Spinal Mechanisms and their Modulation. pp. 74-76.
A. Lissauer described a tract running in the superfi cial
apex of the dorsal horn that differed in microscopic
appearance from the rest of the cord. Ablation of this tract
created analgesia in experimental animals. Later study
revealed that this tract contained the axons of A-delta and
C-fi bers that were entering the cord from the periphery.
These fi bers ascended and descended for one or more
segments in the tract prior to synapsing with dorsal horn
interneurons.
B. The lateral spinothalamic tract and other ventrolateral
cell columns connect dorsal horn interneurons to
supraspinal centers.
C. The posterior spinal columns transmit mainly tactile
information from large, fast conducting A-beta fi bers.
E. Pre-ganglionic sympathetic fi bers enter the sympathetic
ganglion via the gray rami communicantes while postganglionic
sympathetic fi bers exit the ganglion and enter
the spinal nerve through the white rami communicantes.
Source: Schultz D, Board Review 2004

Question 27

Q

Catheter tip granuloma:
A. Have been reported to occur with morphine infusion
B. Is thought to occur in at least 1% of the pump population.
C. Must be treated surgically
D. All of the above.
E. Two of the above.

Answer

A

Answer: E

Source: Feler C, Board Review 2005

Question 28

Q

233. FDA approved indications for SCS include
A. CRPS 1
B. CRPS 2
C. Angina
D. Two of the above
E. None of the above

Answer

A

Answer: E

Source: Feler C, Board Review 2005

Question 29

Q

234. Chronic Intraspinal drug delivery most commonly is
accomplished with:
A. One drug
B. Two drug
C. Three drug
D. Non-programmable pump
E. An epidural catheter

Answer

A

Answer: A

Source: Feler C, Board Review 2005

Question 30

Q

Paddle leads offer which of the following advantages over
percutaneous leads:
A. Increased power requirements
B. Decreased paresthesia overlap for an equivalent array
C. Greater array stability
D. Facilitated implant method
E. User fl exibility in array construction

Answer

A

Answer: C

Source: Feler C, Board Review 2005

Question 31

Q

236. The principal efferent neuron layer of the cerebral
neocortex is
A. II
B. III
C. IV
D. V
E. VI

Answer

A

Answer: D
Explanation:
The cerebral neocortex has a laminar pattern of
organization because of the distribution and size of
neuronal cells and the horizontal pattern of incoming
efferents. It is divided into six layers: Layer I,. primarily a
synaptic area, is the molecular layer. It is the most
superfi cial layer of the cerebral cortex; its most
characteristic cells are horizontal cells.Layer II,the external
granular layer, is characterized by an abundance of
small, densely packed neurons and a paucity of myelinated
fi bers. The dendrites of neurons in this layer project to
layer I, while their axons project to deeper layers. Layer III,
the external pyramidal layer, contains medium-large
pyramidal cells and granule cells. Axons of most
pyramidal cells descend through the cortex, forming
cortical association fi bers, both callosal and
intrahemispherical. Layer IV, the internal granular layer, is
the principal receiving station of the cerebral cortex.
Layer V, the internal pyramidal layer, is the principal
efferent layer of the cortex. This layer contains pyramidal
cells that send their axons through the cortical white
matter to the internal capsule and all subcortical sites
except the thalamus, which receives fi bers from Layer VI.
Layer VI, the fusiform layer, contains fusiform and
pyramidal cells, which are the principal source of
corticothalamic fi bers and contribute to the
intrahemispheric cortical association fi bers. (Afi fi and
Bergman, 340-343; Burt, 451-452)
Source: Neurology Examination and Board Review By
Nizar Souayah, MD and Sami Khella, MD

Question 32

Q

In muscular dystrophy, the actin-binding protein
dystrophin is absent or defective. Dystrophin contains
similar actin-binding domains to the spectrins (I and
II) and a-actinin and has a similar function. Which of
the following is most likely to occur as a result of this
defi ciency?
A. Defi ciency in skeletal muscle actin synthesis
B. Enhanced smooth muscle contractility
C. Loss of binding of the I and M bands to the cell membrane
D. Loss of organelle and vesicle transport throughout the
muscle cell
E. Loss of integrity of the desmosomal components of the
intercalated discs of cardiac muscle

Answer

A

Answer: C
Explanation:
(Alberts, 31e, p 855. Braunwald, 15/e pp 2529-25. Kumar, 6/e, pp 689-690.) Dystrophin, like these other actinbinding
proteins, binds actin to the skeletal muscle
membrane and, therefore, binds I and M bands to the cell
membrane. The inability to bind actin to
plasma membrane of skeletal muscle leads to disruption of
the contraction process, weakness of muscle, and
abnormal running, hopping, and jumping. Gowers’
maneuver is the method used by persons suffering from
muscular dystrophy to stand from a sitting position.
Respiratory failure occurs in these persons because of
disruption of diaphragmatic function.Dystrophin is found
in muscle of all types and is part of a complex that
regulates interactions of the sarcolemma with the
extracellular matrix through associated glycoproteins
(dystrophin -glycoprotein complex). Therefore, loss of
dystrophin causes a destabilization of the sarcolemma.
Muscular dystrophy refers to a group of progressive
hereditary disorders (1/3500 male births) that involve
mutations in the dystrophin gene. Dystrophin is similar in
structure to spectrins I and II and a-actinin. Dystrophin is
absent in Duchenne muscular dystrophy. Becker muscular
dystrophy is a less severe dystrophy in which dystrophin is
defective. Synthesis of actin is not reduced in skeletal
muscle from these patients; in fact, hypertrophy and
pseudohypertrophy (replacement of muscle with
connective tissue and fat) occurs. Microtubules perform
vesicular and organelle transport functions, and
intermediate fi laments not actin form the intracellular
connection in desmosomes.
Source: Klein RM and McKenzie JC 2002.

Question 33

Q

In patient who has had attacks of paroxysmal atrial
tachycardia, an ideal prophylactic drug is
A. Adenosine
B. Procainamide
C. Lidocaine
D. Nifedipine
E. Verapamil

Answer

A

Answer: E
Explanation:
Reference: Hardman, pp 858-874
Because verapamil, a Ca channel blocker, has a selective
depressing action on AV nodal tissue, it is an ideal drug for
both immediate and prophylactic therapy of
supraventricular tachycardia (SVT). Nifedipine, another
Ca channel blocker, has little effect on SVT. Lidocaine and
adenosine are parenteral drugs with short half-lives and,
thus are not suitable for prophylactic therapy.
Procainamide is more suitable for ventricular arrhythmias
and has the potential for serious adverse reactions with
long-term use.
Source: Stern - 2004

Question 34

Q

239. The FDA approved drugs for chronic intrathecal drug
delivery through a pump are:
A. Morphine
B. Bupivicaine
C. Lioresal
D. Prialt
E. Three of the above

Answer

A

Answer: E

Source: Feler C, Board Review 2005

Question 35

Q

Following exposure to acute high threshold thermal
stimulation, what event is likely in local population(s) of
C-fi ber afferents?
A. Rightward shift in their response curve
B. Leftward shift in their response curve
C. A prolonged latency period during which they are nonresponsive
D. All of the above
E. None of the above

Answer

A

Answer: B
Explanation:
C-fi bers show sensitization following exposure to acute
thermal stimli; this leads to enhanced temporal activation
and a decrease in sensitivity threshold to both noxious and
non-noxious stimuli.
Source: Giordano J, Board Review 2005

Question 36

Q

In primary nociceptive afferents, excitatory conduction
is mediated by
A. A-2 purinoreceptors
B. Trk B receptors for nerve growth factor
C. Selective Na (v)1.8 and Na (v)1.9 cationic channels
D. The Silent Nociceptor which is not sensitized
E. All of the above

Answer

A

Answer: C
Explanation:
There are specifi c sodium channels that mediate the propagation and conductance of the action potential in
nociceptive afferents; these have been identifi ed using
molecular biological techniques that have elucidated their
transcriptional and translational precursors.
A-2 purinoreceptors subserve the transduction of the
nociceptive signal in response to adenosine.
Trk B receptors subserve the transduction of the
nociceptive signal in response to BDNF.
A Silent Nociceptor exists, but, is very diffi cult to activate
under normal circumstance. Easily activated after
sensitization.
Source: Giordano J, Board Review 2005

Question 37

Q

The projections of A-delta primary afferents
A. Is identical to C-fi ber afferents
B. Is Multilaminar within the superfi cial dorsal horn
C. Is exclusive to wide dynamic range neurons
D. A-Delta primary afferents project to laminae III, V and
X
E. All of the above

Answer

A

Answer: B
Explanation:
A-delta primary afferents project to laminae I, II, and IIa
of the dorsal horn.
This is anatomically distinct from the projection sites of
C-fi bers in that C-fi bers project to lamina V and not I.
A-delta fi bers appear to form synaptic contacts exclusively
upon NS second order neurons.
Source: Giordano J, Board Review 2005

Question 38

Q

243. The neurochemical effect of the 17 amino acid peptide
dynorphin (1-17) is post- synaptically mediated by which
receptor?
A. Mu type 1
B. Delta
C. Kappa
D. Mu type 3
E. Mu type 2

Answer

A

Answer: C
Explanation:
Dynorphin is the selective endogenous ligand at the kappa
opioid receptor. Endorphins and met-enkephalin are the
endogenous ligands at mu 1 and 2 receptors.
Leu-enkephalin and to a lesser extent, endorphin, are the
endogenous ligands at delta opioid receptors.
Source: Giordano J, Board Review 2005

Question 39

Q

244. The majority of opioid receptors in the lumbar spinal
cord are:
A. Mu-1 and /or 2
B. Delta and Kappa
C. Sigma
D. Mu-3
E. Mu-2

Answer

A

Answer: B
Explanation:
Autoradiographic, pharmacologic, and molecular biologic
investigations have shown that the lumbar spinal cord
contains primarily delta and kappa type opioid receptors.
Mu opioid receptors are found in highest concentration in
the midbrain, forebrain, and rostral (cervico-thoracic)
spinal cord. Mu-3 receptors have been localized to smooth
muscle and leukocytes.
Sigma (PCP) receptors are primarily supratentorial.
Source: Giordano J, Board Review 2005

Question 40

Q

Which is not a projection site of the neospinothalamic
tract neurons that subtend painful afferent volleys?
A. Nucleus reticularis gigantocellularis
B. Nucleus raphe Magnus
C. Periaqueductal grey region
D. All of the above
E. None of the above

Answer

A

Answer: D
Explanation:
The NSTT is a direct pathway to the thalamus.
The paleospinothalamic tract (PSTT) projects to the
brainstem raphe and magnocellular nuclei as well as the
mesencephalic PAG region en route to its thalamic
terminations.
Source: Giordano J, Board Review 2005

Question 41

Q

246. In assessing and characterizing pain, the most useful
distinctions about the typology of pain can best be made
according to:
A. Physiological characteristics
B. Temporal characteristics
C. Subjective characteristics
D. Radiological Investigations
E. Nerve Conduction studies

Answer

A

Answer: A
Explanation:
Physiologic distinctions (eg. nociceptive versus
neuropathic)are useful referents that describe the nature of
pain relevant to its typologic classifi cation.
Temporal characteristics (immediate, acute, chronic) are
often laden with ambiguity regarding relative length of time and are of little use in classifying the functional or
pathologic basis of pain.
Subjective characteristics are useful referents in describing
the cognitive dimensions of pain, but may not directly
refl ect underlying neural processes that are explicitly
relevant to pathology for clinical purposes.
Source: Giordano J, Board Review 2005

Question 42

Q

247. The patient who favors a particular area and moves
compensatorily to (reduce) pain sensation is said to be
exhibiting:
A. Guarding
B. Allodynia
C. Antalgia
D. Hyperalgesia
E. Dystocia

Answer

A

Answer: C
Explanation:
A. Guarding is a patient’s reactions to protect or retract a
painful bodily region against contact or insult.
B. Allodynia is the sensation of pain produced by nonnoxious
stimuli and occurs as a consequence of peripheral
and/or central sensitization.
C. Antalgia literally translates as “against pain” and is any
posture or movement that functions to prevent
provocation of nociception.
D. Hyperalgesia is hypersensivity to a painful stimulus
dysthesia is unpleasant abnormal sensation.
E. Dystilosia is abnormal or diffi cult labor.
Source: Giordano J, Board Review 2005

Question 43

Q

Which of the following is involved in glomerular
fi ltration?
A. Facilitated diffusion of large anionic proteins
B. Maintenance of a charge barrier
C. A physical barrier consisting of type II collagen
D. Filtration slits between adjacent endothelial cells
E. A positive charge in the basement membrane due to the
presence of heparan sulfate

Answer

A

Answer: B
Explanation:
(Junqueira, 9/e, pp 360-364, 372-373.) The glomerular
fi ltration barrier is a physical and charge barrier that
exhibits selectivity based on molecular size and charge.
The barrier is formed by three components: (1)
glomerular capillary endothelial cells, (2) glomerular
basement membrane, and (3) podocyte layer. The presence
of collagen type IV in the lamina densa of the basement
membrane presents a physical barrier to the passage of
large proteins from the blood to the urinary space.
Glycosaminoglycans, particularly heparan sulfate, produce
a polyanionic charge that binds cationic molecules.
Filtration slits are found between adjacent podocyte foot
processes and provide a gap of approximately 50 μm. The
foot processes are coated with a glycoprotein called
podocalyxin, which is rich in sialic acid and provides
mutual repulsion to maintain the structure of the fi ltration
slits. It also possesses a large polyanionic charge for
repulsion of large anionic proteins.
Source: Klein RM and McKenzie JC 2002.

Question 44

Q

A known NMDA/Glutamate receptor antagonist agent,
such as topiramate would be most useful against:
A. A-delta mediated thermal pain
B. C-fi ber mediated neuropathic pain
C. C-fi ber mediated mechanical nociceptive pain
D. A-delta mediated cold
E. All of the above

Answer

A

Answer: B
Explanation:
C-fi ber mediated neuropathic pain is primarily subserved
by glutamate-induced activation of both NMDA and
mGlu receptors
Source: Giordano J, Board Review 2005

Question 45

Q

A lesion of the axons of motor neurons that innervate
skeletal muscle (lower motor neurons) will result in
which one of the following consequences?
A. Paralysis of individual muscles on the contralateral side
of the lesion
B. A paradoxical increase in refl ex activity
C. Compensatory increase in muscle mass
D. Increase in muscle tone
E. Sealing off of the axoplasm

Answer

A

Answer: E
Explanation:
(Kandel, pp 1108-1109.) The cutting of a nerve tract
within the brain or of a peripheral nerve results in the following sequence: both ends of the cut axon immediately
seal off the axoplasm, retract, and begin to swell; there is
rapid degeneration of the axon and the myelin sheath; the
macrophages from the general circulation enter the area
and phagocytose axonal debris; there is also a proliferation
of glial cells, which act as phagocytes; and fi brous
astrocytes proliferate in the central nervous system,which
leads to glial scar formation around the zone of trauma
that often blocks the course taken by regenerating axons
and causes a barrier against the reformation of central
connections. Degeneration spreads along the axon in both
directions from the zone of trauma. The retrograde
reaction in the proximal segment usually progresses a
short distance and appears in the cell body after 2 to 3
days.
In the distal segment, degeneration appears in the axon
terminal in about I day, and within 2 weeks the distal
synapses degenerate completely.
Source: Ebert 2004

Question 46

Q

One of the factors that contributes to the induction of
Type-II pain is:
A. “Un-masking” of post-synaptic NMDA receptors within
the algesic neuraxis
B. Down-regulation of AMPA receptors within the spinal
neural circuit
C. Increased serotonergic output from the nucleus reticularis
D. All of the above
E. None of the above

Answer

A

Answer: A
Explanation:
Glutamate-induced activation of post-synaptic AMPA
receptors “ungates” an ionotropic NMDA receptor that is a
functional substrate of type II pain.
AMPA receptors do not appear to be sensitized or
regulated as a consequence of continued exposure to
glutamate.
Serotonin is produced primarily in neurons of the raphe
nulei, not the nucleus reticularis; increased output of
bulbospinal serotonergic neurons produces analgesia.
Source: Giordano J, Board Review 2005

Question 47

Q

C-fi ber primary afferents
A. Subtend transmission of Polymodal high threshold
stimuli
B. Subtend transmission of high threshold thermal input
only
C. Project exclusively onto Nociceptive specifi c second-order
afferents
D. Project exclusively onto wide dynamic range neurons
E. All of the above

Answer

A

Answer: A
Explanation:
C-fi bers respond to high threshold thermal, mechanical,
and noxious chemical stimuli.
C-fi bers project to laminae II, IIa, and V and synapse upon
both NS and WDR second order neurons.
Source: Giordano J, Board Review 2005

Question 48

Q

Acute, nociceptive pain:
A. Characteristically causes de novo expression of alpha
adrenergic receptors in dorsal root ganglia
B. Decreases activity in bulbospinal pathways
C. Decreases adrenomedullary effects
D. Can engage sympathetic function to suppress pain perception
through bulbospinal and limbic noradrenergic
mechanisms
E. Induces decreased activity in ventral posterior lateral
and medial nuclear groups of the thalamus

Answer

A

Answer: Answer D
Explanation:
Reference:
Bonica’s Management of Pain, 3rd Ed: Ch 4. Spinal
mechanisms and modulation.
Acute nociceptive pain can engage bulbospinal
(descending) and ascending noradrenergic pathways to the
limbic system to suppress pain sensation and perception
through inhibition of afferent dorsal horn input and
supratentorial, “attentional analgesia” respectively. Such
pain does not lead to novel expression of alpha adrenergic
receptors in the periphery or DRG, as is commonly seen in
chronic pain.Acute nociceptive pain can enhance
activation of the adrenal medullary system, causing a
release of adrenal opioids that subsequently produce
analgesia.As well, such pain directly engages the
neo-and paleo-spinal thalamic tracts to activate the
ventralposteriolateral and medial thalamic nuclei,
respectively.
Source: Giordano J, Board Review 2005

Question 49

Q

The following is true regarding nitric oxide (NO):
A. It is a large molecular neurotransmitter that is actively
transported across neural membrane
B. It induces potent vasoconstriction and is inhibitory to
infl ammatory pain
C. It is a direct product of phosopholipase-A
D. It is localized only within the vascular endothelium
E. It is a rapidly synthesized, small molecular modulator
that is produced in peripheral and central neurons and
can easily diffuse into non-neural tissues

Answer

A

Answer: E
Explanation:
Reference:
Bonica’s Management of Pain, 3rd Ed: Ch 3. Peripheral
pain mechanisms and nociceptive plasiticity. Nitric oxide
is a small gaseous molecule that is rapidly synthesized in
neural and vascular endothelial tissue via convergent
pathways that ultimately increase the catalytic activity of
nitric oxide synthase. NO easily and passibly diffuses
across neural and vascular membranes and can engage
second messenger signaling systems to initiate
vasodilatation and promote infl ammation and resultant
infl ammatory pain.
Source: Giordano J, Board Review 2005

Question 50

Q

One mechanism through which sympathetic and
nociceptive afferent fi bers can be cross-sensitized is
A. Through remodeling of C-fi ber projections into spinal
sympathetic ganglia
B. By increased production of cyclo-oxygenase-2 in sympathetic
pre-ganglionic fi bers
C. Through ephaptic conduction and/or ionic spread
D. By down-regulation of alpha adrenergic receptors on
peripheral C-fi bers
E. By retraction of C- and A-beta fi ber terminals from
lamina VII

Answer

A

Answer: C
Explanation:
Reference:
Bonica’s Management of Pain, 3rd Ed: Ch 3. Peripheral
pain mechanisms and nociceptive plasiticity. Also Bonica’s
Management of Pain,3rd Ed: Ch 4. Spinal mechanisms and
modulation. Nociceptive afferents and sympathetic fi bers
are frequently anatomically co-located, and adjacent
within the dorsal root ganglia and peripheral nerve trunks.
As well, peripheral tissue insult can produce a pathologic
intermingling of nociceptive afferent and sympathetic
fi bers both in neuromas and in non-neuromatous insult.
These anatomically adjacent fi bers can, and frequently do
permit ephaptic conduction signal transmission through
low resistance zones and by ionic spread through shared,
transmembrane ion channels. C-fi ber projections do not
remodel into spinal sympathetic ganglia; sympatheticnociceptive
afferent fi ber interaction is not reliant upon
arachidonic acid cascade (i.e. Cox-2 mediated) products,
and alpha adrenergic receptors are frequently upregulated
on C-fi bers consequential to longitudinal sympathetic
stimulation/sensitization.
Source: Giordano J, Board Review 2005

Question 51

Q

Sympathetically mediated pain
A. Frequently produces temporally- dependent, variable
sudo- and vaso- motor responses
B. Involves a loss of A-beta mechanoreceptors from lamina
II in the dorsal horn
C. Is refl ective of increased number, frequency and duration
of parasympathetic discharge
D. Is explicitly dermatonal
E. Characteristically does not involve thermal effects along
the peripheral nerve territory

Answer

A

Answer: A
Explanation:
Reference:
Bonica’s Management of Pain, 3rd Ed: Ch 3. Peripheral
pain mechanisms and nociceptive plasiticity.
Sympathetically mediated pain may initially produce
vasodilatation and hyperhydrosis. However, as this pain
persists, loss of vascular tone produces reactive
vasoconstriction and prolong sympathetic actively alters
sudomotor responses to produce a characteristic
anhydrosis. Such thermal and sudomotor effects are not
explicitly dermatonal but frequently involve the territory
of multiple branches of affective peripheral nerve(s).
Characteristically, parasympathetic modulation does not
produce rebound or compensatory effects and the
expression of alpha-adrenergic receptors on peripheral abeta
mechanoreceptors may be an initiative mechanism
that ultimately affects genomic-phenotypic expression and
can enhance a-beta projections into laminae II of the spinal cord. Source: Giordano J, Board Review 2005

Question 52

Q

Long term, durable sympathetic activation
A. Can induce expression of alpha-adrenergic receptors on
sensitized C-nociceptive fi bers
B. Produces adrenomedullary mediated pain modulation
C. Causes desensitization of a-beta mechanoreceptors
D. Produces a rightward shift in nociceptive threshold and
fi ring patterns
E. Is functional against neuropathic pain

Answer

A

Answer: A
Explanation:
Reference:
Bonica’s Management of Pain, 3rd Ed: Ch 3. Peripheral
pain mechanisms and nociceptive plasticity. Also Bonica’s
Management of Pain, 3rd Ed: Ch4. Spinal mechanisms and
modulation. Longitudinal sympathetic activation can
induce denovo expression of alpha adrenergic receptors on
(chemically pre-sensitized) nociceptive C-fi ber afferents
and a-beta mechanoreceptors. Direct stimulation of these
alpha-receptors by epinephrine released from sympathetic
terminals can sensitize a-beta mechanoreceptors,produce a
leftward shift in fi ring thresholds of a-beta and C-fi bers
and induce both peripheral and ultimately central
sensitization. Chronic sympathetic activation does not
produce stress induced modulation of nociceptive or
neuropathic pain.
Source: Giordano J, Board Review 2005

Question 53

Q

An increase in the output of a primary and/or secondorder
pain afferent as a consequence of increased
stimulation over a broader surface area of the affected
region is known as:
A. Temporal summation
B. Allodynia
C. Spatial summation
D. Cross-sensitization
E. All of the above

Answer

A

Answer: C
Explanation:
Pain afferents are capable of summating output as a
consequence of enhanced stimulation of numerous
transductive receptors within their receptive fi eld(s). This
is known as spatial summation; the greater the surface area
stimulated,the greater the response output (amplitude and
duration) of the respective nociceptive afferent.
Temporal summation involves an increased number of
noxious stimuli activating the receptive fi eld of a given
nociceptor per unit time.
Allodynia is the sensation of pain produced by nonnoxious
stimuli as a result of nociceptor sensitization.
Cross-sensitization involves the enhanced sensitivity of a
nociceptor to distinct noxious stimuli following activation
by another type of noxious stimuli. This process is due to
enhanced transcription, translation, and expression of
multiple membrane receptors that subserve transduction
of distinct, specifi c noxious input.
Source: Giordano J, Board Review 2005

Question 54

Q

259. An absent ankle refl ex in a 35 year-old patient with acuteonset radicular pain would most likely involve which
nerve root?
A. L3
B. L4
C. L5
D. S1
E. S2

Answer

A

Answer: D

Source: (Raj, Pain Review, 2nd Ed., page 68)

Question 55

Q

The following is true regarding nitric oxide:
A. It is preformed in the presynaptic terminal and stored in
vesicles prior to release.
B. It is considered a large molecule neurotransmitter and is
actively transported across neural synapses.
C. It is synthesized in the postsynaptic terminal by the enzyme
cyclo-oxygenase.
D. It is found only in the dorsal horn
E. It is synthesized almost instantly in the presynaptic
terminal and then diffuses into adjacent postsynaptic
neurons.

Answer

A

Answer: E
Explanation:
Reference:
Bonica’s Management of Pain, Third Edition, Chapter 3,
Peripheral Pain Mechanisms and Nociceptor Plasticity. pp.
40-42.
Nitrous oxide is a diffusible gas with numerous
intracellular and extracellular effects. It is considered a
small molecule neurotransmitter but it differs from other
neurotransmitters in that it is not stored in vesicles.
Instead it is synthesized almost instantly as needed within
the presynaptic terminal by the action of the enzyme nitric
oxide synthase. Once created it diffuses out of the presynaptic terminal within seconds and diffuses into
adjacent neurons to affect numerous intracellular
metabolic processes which modify neuronal excitability
for seconds, minutes or longer. The actions of nitric oxide
early in the infl ammatory response are largely protective
with facilitation of blood fl ow, moderation of cell toxicity
and scavenging of reactive oxygen molecules. Later in the
infl ammatory cascade, nitric oxide becomes damaging and
cytotoxic. Nitric oxide is thought to be involved in the
development of neuropathic pain states. It is prevalent in
various tissues including brain, gonads and dorsal horn.
Source: Schultz D, Board Review 2004

Question 56

Q

261. The precentral gyrus and corticospinal tract are essential
for
A. Vision
B. Olfaction
C. Auditory identifi cation
D. Kinesthesia
E. Voluntary movement

Answer

A

Answer: E
Explanation:
(Guyton, pp 638-640.) The precentral gyrus is the motor
area of the cortex and the corticospinal tract is the
pyramidal tract proper. These two structures are essential
for voluntary movement. A supplementary motor area,
whose function is still unknown, exists on the medial side
of the hemisphere.

Question 57

Q

262. The middle cerebellar peduncle contains afferent fi bers
conveyed in the following tracts
A. Dorsal spinocerebellar
B. Ventral spinocerebellar
C. Tectocerebellar
D. Pontocerebellar
E. Vestibulocerebellar

Answer

A

Answer: D
Explanation:
(Guyton, pp 648-650.) The middle cerebellar peduncle
contains afferent fi bers conveyed in the pontocerebellar
tract, which carries impulses from the motor area as well
as other parts of the cerebellar cortex except the
fl occulonodular lobe. The dorsal spinocerebellar and
vestibulocerebellar afferent tracts enter the cerebellum via
the inferior peduncle. The ventral spinocerebellar and
tectocerebellar tracts enter via the superior cerebellar
peduncle.

Question 58

Q

At the neuromuscular junction, action potentials are
coupled to neurotransmitter release by voltage-gated
A. Ca2+ channels
B. Na+ channels
C. K+ channels
D. Cl- channels
E. Gap junctions between the presynaptic terminal and the
muscle cell

Answer

A

Answer: A
Explanation:
(Junqueira, 9/e, pp 157-159,186,194. Kandel, 4/e, pp
43,175-177, 183, 210-211.)
A. Ca2+ entry through specifi c channels results in fusion
of acetylcholine-containing synaptic vesicles with the
presynaptic membrane and ultimately the release of
neurotransmitter. Neuromuscular, or myoneural,
junctions represent the site at which end feet (boutons
terminaux) come in close proximity to the surface of
muscle cells. The arrangement is similar to that found in a
synapse, and a neuromuscular junction can be considered
the best-studied synapse.
Ca2+ infl ux into the end feet may have a direct effect on
phosphorylation of synapsin I, a vesicular membrane
protein, which in its nonphosphorylated state blocks
vesicle fusion with the presynaptic membrane.
B, C, D. Na+,K+ , and Cl-voltage-gated channels are
involved in the transmission of a nerve impulse but are
not involved in the coupling of the action potential ( an
electrical signal) to neurotransmitter release (a chemical
alteration).
Source: Klein RM and McKenzie JC 2002.

Question 59

Q

264. Which of the following is absent from smooth muscle
cells?
A. Troponin
B. Calmodulin
C. Calcium
D. Myosin light chain kinase
E. Actin and tropomyosin interactions similar to skeletal
muscle

Answer

A

Answer: A
Explanation:
(Alberts, 3/e, pp 856-857. Junqueira, 9/e,) Smooth muscle
is the least specialized type of muscle and contains no
troponin. The contractile process is similar to the actinmyosin
interactions that occur in motility of nonmuscle
cells. In the smooth muscle cell, actin and myosin are
attached to intermediate fi laments at dense bodies in the
sarcolemma and cytoplasm.Dense bodies contain a-actinin
and, therefore, resemble the Z lines of skeletal muscle.
Contraction causes cell shortening and a change in shape
from elongate to globular. Contraction occurs by a sliding
fi lament action analogous to the mechanism used by thick
and thin fi laments in striated muscle. The connections to
the plasma membrane allow all the smooth muscle cells in
the same region to act as a functional unit. Sarcoplasmic
reticulum is not as well developed as that in the striated
muscles. There are no T tubules present; however,
endocytic vesicles called caveolae are believed to function
in a fashion similar to the T tubule system of skeletal
muscle.
When intracellular calcium levels increase, the calcium is
bound to the calcium-binding protein calmodulin. Ca2+ -
calmodulin is required and is bound to myosin light chain
kinase to form a Ca2+-calmodulin-kinase complex. This
complex catalyzes the phosphorylation of one of the two
myosin light chains on the myosin heads. This
phosphorylation allows the binding of actin to myosin. A
specifi c phosphatase dephosphorylates the myosin light
chain, which returns the actin and myosin to the inactive,
resting state.The actin-tropomyosin interactions are
similar in smooth and skeletal muscle.
Smooth muscle cells (e.g., vascular smooth muscle cells)
also differ from skeletal muscle cells in that they are
capable of collagen, elastin, and proteoglycan synthesis,
which is usually associated with fi broblasts.
Source: Klein RM and McKenzie JC 2002.

Question 60

Q

The principal action of the Quadratus Lumborum muscle
is:
A. Lateral fl exion of the lumbar spine
B. Axial rotation of the lumbar spine
C. Extension of the lumbar spine
D. Fixation of the 12th rib during respiration
E. Lateral rotation of the lumbar spine

Answer

A

Answer: D
Explanation:
D. The principal action of the Quadratus Lumborum (QL)
muscle is to fi x the 12th rib during respiration. It is a weak
lateral fl exor of the lumbar spine.
The QL is a fl at rectangular muscle that arises below
from the iliolumbar ligament and the adjacent iliac crest.
The insertion is into the lower border of the twelfth
rib and the transverse processes of the upper four lumbar
vertebrae.
Patients usually present with low back pain.
They have diffi culty turning over in bed, increased
pain with standing upright. Coughing or sneezing may
exacerbate their pain.
Source: Chopra P, 2004

Question 61

Q

Which of the following is an antiarrhythmic agent that
has relatively few electrophysiologic effects on normal
myocardial tissue but suppresses the arrhythmogenic
tendencies of ischemic myocardial tissues?
A. Propranolol
B. Procainamide
C. Quinidine
D. Lidocaine
E. Disopyramide

Answer

A

Answer: D
Explanation:
Reference: Hardman, pp 865-867
Lidocaine usually shortens the duration of the action
potential and, thus, allows more time for recovery during
diastole. It also blocks both activated and inactivated Na
channels. This has the effect of minimizing the action of
lidocaine on normal myocardial tissues as contrasted with
depolarized ischemic tissues. Thus lidocaine is particularly
suitable for arrhythmias arising during ischemic episodes
such as myocardial infarction (MI).
Source: Stern - 2004

Question 62

Q

The mechanism of the transcutaneous electrical nerve
stimulation (TENS) in relieving pain is
A. Direct electrical inhibition of type A-delta and C fi bers
B. Depletion of neurotransmitter in nociceptors
C. Hyperpolarization of spinothalamic tract neurons
D. Activation of inhibitory neurons
E. Distortion of nociceptors

Answer

A

Answer: D
Explanation:
Transcutaneous nerve stimulation is low-intensity, mixedfrequency
(2 and 100 Hz) electrical stimulation that is
thought to produce analgesia by releasing endorphins.
This technique is effective in treating nociceptive and
deafferentation syndromes by a mechanism that is not
reversed by naloxone. The mechanism is thought to be
activation of inhibitory neurons and/or release of
endogenous opiates.
Source: Hall and Chantigan.

Question 63

Q

The intensity of a signal that is transmitted to the brain
can be increased by increasing the frequency of impulses
traveling along a single fi ber. This is called
A. spatial summation
B. after-discharge
C. temporal summation
D. recruitment
E. saltatory conduction

Answer

A

Answer: C
Explanation:
The overall pattern of several impulses relaying similar
information is termed a signal.
A. The intensity of signal (such as pain) that is transmitted
to the brain can be increased by increasing the number of
parallel fi bers participating (spatial summation).
B. After-discharge is production of output signals for
prolonged periods by a single input stimulus.
C. An intensity of signal (such as pain) that is transmitted
to the brain can be increased by increasing the frequency
of impulses traveling along a single fi ber is called temporal
summation.
D. The increase in the number of participating fi bers as the
intensity of a signal increases is termed recruitment.
E. Saltatory conduction is the process of successive
excitation of nodes of Ranvier by an impulse that jumps
between successive nodes.

Question 64

Q

269. Acute intermittent porphyria is a contraindication of the
use of
A. Enfl urane
B. Nitrous oxide (N2O)
C. Ketamine
D. Diazepam
E. Thiopental

Answer

A

Answer: E
Explanation:
Reference: Hardman, p 323.
Induction of anesthesia by parenteral administration of
thiopental sodium and other barbiturates is absolutely
contraindicated in patients who have acute intermittent
porphyria. These patients have a defect in regulation of
delta-aminolevulinic acid synthetase; thus, administration
of barbiturate that increases this enzyme may cause a
dangerous increase in levels of porphyrins. Administration
of a barbiturate would exacerbate the symptoms of
gastrointestinal and neurologic disturbances, cause extensive demyelination of peripheral and cranial nerves,
and could lead to death.
Source: Stern - 2004

Answer 65

A

Answer: C
Explanation:
(Baum, pp 569-570.)
B. Most glands receive either direct neural control from
the brain or indirect control from hormones secreted by
the hypothalamus.
C. The parathyroids are notably free of brain control; in
regulating calcium metabolism, they in turn are regulated
by blood levels of calcium.
D. Thyroid secretion is subject to hypothalamic control,
whereas insulin secretion depends in part on adrenergic
infl uence from the autonomic nervous system.
Source: Ebert 2004

Answer 66

A

Answer: C
Explanation:
(Kandel, pp 286-296.)
C. Under stressful conditions, the organism secretes
endorphins and ACTH together. Proopiocortin is a
common precursor.
The close link between endorphins and ACTH suggests
that they serve a mediation function for a closely related
set of adaptation responses.
They can facilitate one’s response to stress and at the
same time help one to withstand pain and mobilize for
coping activity to deal with the stressful challenge or
threat. Almost every physical stress agent increases plasma
levels of ß-endorphin as well as adrenocorticotropin and
corticosterone.
Source: Ebert 2004

Answer 67

A

Answer: A
Explanation:
(Kandel, pp 936-947.)
The two most frequent organic causes are disruption of
normal circadian rhythms and the inevitable consequences
of aging.
A. The most common disruptions of normal circadian
rhythms are related to travel (Jet lag) and behavioral
changes in one’s normal daily routine, such as napping,
irregular sleep hours and conditions, alteration in meal
times, and unusual work schedules.
The most common psychosocial cause of insomnia is
emotional disturbance
Normal aging is the next most common factor as it is
more diffi cult to reset one’s biologic clock the older one
gets. It has been estimated that most people over age 60
sleep only about 5.5 h per day, and since stage 4 NREM sleep also declines with age, the lighter stages of NREM
` sleep allow the person to awaken more often, sometimes
generating the worry that one cannot sleep or that one is
not getting enough sleep.
B. Accumulation of hepatic enzymes is a frequent side
effect of prolonged use

Answer 68

A

Answer: A
Explanation:
A complex pathway allows opportunities for alteration
and modulation of the incoming pain signals by other
signals, including the inhibiting impulses that descend
from the brain.
A.The gate control theory proposes that there is a structure
in the dorsal horn of the spinal cord that acts as a gate for
increasing or decreasing nerve impulse fl ow from the
peripheral fi bers to the central nervous system. This
allows sensory input to be reviewed and modifi ed at the
gate before it evokes pain. Sensory input is increased or
decreased by the activity of large diameter fi bers (Aß
fi bers), small diameter fi bers (Ad and C fi bers), and
descending fi bers from the brain.
Impulses from the large fi bers can close the gate, inhibiting
transmission, while activity from the small fi bers can open
the gate to enhance transmission.
Efferent impulses from the brain provide further
infl uence and the access route for the psychological
processes of anxiety, depression, attention, and past
experience to alter the gate and thus directly infl uence the
pain perception process.
When the output of the spinal cord T cells exceeds a
critical threshold level, neuromechanisms are activated
that are responsible for both pain perception and
behavioral responses to the pain.
B. Nociceptors are nerve endings that transmit pain.
C. The specifi city theory states that there are specifi c
sensory receptors for touch, warmth, and pain.
D. Polymodal nociceptors are nerves that maximally
respond to mechanical and temperature stimulation.
E. The pattern theory states that pain sensations are the
result of nerve impulse patterns being transmitted from
and coded at the peripheral site.
(Baum, pp 313-321.)
Source: Ebert 2004

Answer 69

A

Answer: C
Explanation:
Reference: Katzung, pp 612, 1073.
Sulfasalazine is a dervative of sulfapyridine and 5-
aminosalicylic acid. It is not signifi cantly absorbed
following oral administration. The 5-aminosalicyclic acid
moiety is released by intestinal bacterial action.
Slefasalazine is more effective in maintaining than causing
remission in ulcerative colitis. Celocoxib (a selective
cyclooxygenase inhibitor), infl iximab ( a chimeric
monoclonal antibody), and penicillamine (an analogue of
cysteine) have a role in the treatment of rheumatoid
arthritis. Naproxen a nonselective cyclooxygenase
inhibitor, is indicated for usual rheumatological
indications.
Source: Stern - 2004

Answer 70

A

Answer: A

Source: (Raj, Pain Review 2nd Ed., page 62).

Answer 71

A

Answer: B

Source: (Raj, Pain Review, 2nd Ed., page 62)

Answer 72

A

Answer: D
Source: Raj P, Pain medicine - A comprehensive Review -
Second Edition

Answer 73

A

Answer: A
Explanation:
(Kandel, pp 936-947.)
Paradoxical sleep is a term given to REM sleep, which is
considered paradoxical because its
electroencephalographic pattern resembles that of the alert
waking state. Dreaming occurs during REM sleep.
A. When a person is repeatedly awakened during
dreaming, a dream deprivation occurs and there is a
rebound phenomenon of increased frequency and
lengthening of dreaming when the person is permitted to
sleep normally.
B. The earlier studies suggested the presence of bizarre
behavior, anxiety, irritability, and nightmares.
However, more recent studies have found no such
changes in humans even after 16 days of deprivation of
dream sleep.
C.Dream deprivation does not result in a major
decrement in psychological or intellectual functions (as
does sleep deprivation), but it does appear to retard the
memory formation of emotionally toned words.
Source: Ebert 2004

Answer 74

A

Answer: B
Explanation:
The gray matter of the spinal cord is divided into the 10
laminae of Rexed, which form a cytoarchitectonic map of
this spinal cord that correlates well with synaptic
connections and neurophysiological data. Laminae I, II,
III, and IV encompass most of the dorsal horn, which receives primary sensory fi bers. Lamina I corresponds to
the nucleus postmarginalis, Lamina II corresponds to the
substantia gelatinosa and lamina III and IV correspond to
the nucleus proprius dorsalis. All these nuclei integrate
and modulate sensory information. They relay sensory
information to higher centers like the cerebellum,
thalamus, and brain stem. (Afi fi and Bergman, 66)
Source: Neurology Examination and Board Review by Nizar Souayah, MD and Sami Khella, MD

Answer 75

A

Answer: B
Explanation:
A. Most A-delta and C fi bers are non-myelinated.
B. Most A-delta and C fi bers end as free nerve endings.
C. A-delta fi bers terminate in the epidermis, while C
fi bers may end in the superfi cial dermis.
D. The transduction of noxious stimulation occurs in the
free nerve ending.
E. They do not terminate in specialized structures.
Source: Kahn and Desio

Answer 76

A

Answer: E

Source: Rozen. Pain Practice: SEP 2001

Answer 77

A

Answer: D
Explanation:
Reference: Hardman, pp 855-856.
Propranolol, as well as other nonselective beta blockers,
tends to slow the rate of recovery in a hypoglycemic attack
caused by insulin. Beta blockers also mask the symptoms
of hypoglycemia and may actually cause hypertension
because of the increased plasma epinephrine in the
presence of a vascular beta2 blockade.
Source: Stern - 2004

Answer 78

A

Answer: C
Explanation:
Reference: Hardman, pp 870-871.
Quinidine is often given in conjunction with digitalis. It
has been found by pharmacokinetic studies that this
combination results in quinidine’s replacing digitalis in
tissue binding sites (mainly muscle), thus raising the
blood level of digitalis and decresing its volume of
distribution. A mechanism by which quinidine interferes
with the renal excretion of digitalis has also been
proposed.
Source: Stern - 2004

Answer 79

A

Answer: A
Explanation:
General somatic efferent fi bers of the oculomotor nerve
arise from the oculomotor nucleus situated near the
midline of the midbrain at the level of the superior
colliculus. This nucleus is formed by subnuclei for each of
the extraocular muscles. The superior rectus muscle
receives innervation from neurons in the contralateral subnucleus. The levator palpebral superioris muscle
receives innervation from a medial subnucleus. The
inferior rectus, medial rectus, and inferior oblique muscles
receive innervation from ipsilateral subnuclei. (Burt,
403-406)
Source: Neurology Examination and Board Review By
Nizar Souayah, MD and Sami Khella, MD

Answer 80

A

Answer: C
Explanation:
Climbing fi bers are axons of neurons originating from the
contralateral inferior olivary nucleus that project to all
areas of the cerebellar cortex. Climbing fi bers are
excitatory. Aspartate is the most likely transmitter for
these fi bers. Each single climbing fi ber establishes 1000
to 2000 synaptic contacts with its Purkinje cell. When the
climbing fi bers fi re, there is a massive synchronous
depolarization of Purkinje cells, which activates Ca++
channels in the dendritic membrane. The major source of
climbing fi bers in the cerebellum is the inferior olive.
Degeneration of the inferior olive (seen in olivocerebellar
atrophy) induces a drop in aspartate level in the
cerebrospinal fl uid. (Afi fi and Bergman, 313-314)
Source: Neurology Examination and Board Review By
Nizar Souayah, MD and Sami Khella, MD

Answer 81

A

286. Answer: C
Explanation:
Older antipsychotics are being phased out because of the
risk of EPS
Source: Boswell MV, Board Review 2004

Answer 82

A

Answer: D
Explanation:
Reference: Hardman, pp 11110-1113.
Streptomycin and other aminoglycosides can elicit toxic
reactions involving both the vestibular and auditory
branches of the eighth cranial nerve. Patients receiving
an aminoglycoside should be monitored frequently for any
hearing impairment owing to the irreversible deafness that
may result from its prolonged use.None of the other
agents listed in the question adversely affect the function
of the eighth cranial nerve.
Source: Stern-2004

Answer 83

A

Answer: A
Explanation:
The cerebellar cortex contains three laminated cellular
layers: the outermost molecular cell layer, a sheet of single
large neurons; the Purkinje cell layer; and a deeper
granular cell layer. These layers contain six types of
neurons; basket, satellite, Purkinje, Golgi, granule cells,
and the relatively rare Legato cells. Pyramidal cells are the
most abundant cells of the cerebral cortex neuron types,
are not found in the cerebellum, and are the most
characteristic of the cerebral cortex. (Afi fi and Bergman,
308-310)
Source: Neurology Examination and Board Review By
Nizar Souayah, MD and Sami Khella, MD

Answer 84

A

Answer: D
Explanation:
Reference: Katzung, p 275.
Cimetidine is an H2 antagonist that decreases gastric acid
secretion. Sumatriptan is a 5-HT1D serotonin agonist.
Cyproheptadine acts as a histamine and serotonin
antagonist. Ondansetron is a serotonin antagonist.
Fluoxetine is an antidepressant agent that selectively
inhibits serotonin reuptake.
Source: Stern - 2004

Answer 85

A

Answer: B
Explanation:
The trigeminal nerve has three sensory nuclei: The spinal
nucleus, the main sensory nucleus and the mesencephalic
nucleus. The spinal nucleus of the trigeminal nerve is a
long column of neurons extending from the point of entry
of the trigeminal nerve to the upper cervical spinal cord.
Itis divided into three parts: The oral part, responsible for
tactile sensation from the oral mucosa; the interpolar part,
receiving efferents for dental pain; and the caudal part,
receiving pain and temperature sensations from the face.
Most of the small efferent fi bers of the spinal tract of the
trigeminal nerve terminate in the spinal nucleus. Most of
the efferent large fi bers that originate from the trigeminal
ganglion end in the main sensory nucleus and are
responsible for the transmission of discriminative touch.
The mesencephalic nucleus is located at the rostral pons.
It receives efferent fi bers conveying kinesthesia and
pressure from the teeth, periodontium, hard palate,
joint capsules, the stretch receptors from the muscles of
mastication.It sends efferent fi bers to the cerebellum, the
thalamus, the motor nuclei of the brain stem,and the
reticular formation.
The motor nucleus of the trigeminal nerve provides
somatic visceral efferents that innervate the muscles of
mastication via the mandibular division and contains ?
and ? motor neurons. (Afi fi and Bergman, 171-175)
Source: Neurology Examination and Board Review By
Nizar Souayah, MD and Sami Khella, MD

Answer 86

A

Answer: B
Explanation:
The monoaminergic projections to the cerebellum
originate from the pontine raphe nuclei,the locus ceruleus,
and the hypothalamus. The raphe nuclei are the source of
serotoninergic projections to both the granular and
molecular layers. The locus ceruleus is the source of
noradrenergic projection to the three layers of the
cerebellar cortex. The dorsomedial, dorsal, and lateral
areas of the hypothalamus are the sources of histaminergic
projections to all three layers of the cerebellar cortex.
(Afi fi and Bergman, 322)
Source: Neurology Examination and Board Review By
Nizar Souayah, MD and Sami Khella, MD

Answer 87

A

Answer: D
Explanation:
The olfactory pathway is the only sensory pathway that
does not project to the thalamus. The olfactory nerve penetrates the cribriform plate of the ethmoid bone and
enters the olfactory bulb to synapse with the second-order
neurons: mitral and tufted cells. The axons of the secondorder
neurons course posteriorly as the olfactory tract in
the orbital surfaces of the frontal lobe and project to the
primary olfactory cortex in the temporal lobe. (Parent,
748-754)
SOURCE: Souayah, N, and Khella S; Neurology
Examination & Board Review; McGraw-Hill, New York.
Source: Neurology Examination and Board Review By
Nizar Souayah, MD and Sami Khella, MD

Answer 88

A

Answer: A
Explanation:
(Guyton, p 516-517, 523.) Presynaptic inhibition caused
by interneurons that secrete a transmitter which increases
the Cl- conductance of the presynaptic nerve ending. The
increase in Cl- conductance causes a partial depolarization
of the presynaptic nerve ending and a decrease in the
magnitude of the action potential in the presynaptic nerve
ending. Because the amount of mediator released at the
synapse is related to the magnitude of the action potential,
less transmitter is released and the fi ring rate of the
postsynaptic alpha motoneuron is decreased. Presynaptic
inhibition does not change the membrane potential of the
alpha motoneuron, and therefore the membrane potential
of the alpha motoneuron is not affected.

Answer 89

A

Answer: B
Explanation:
A. The load decreases signifi cantly in supine position.
B. With the patient sitting with the back unsupported or
sitting and bending over, the load shows greater increase.
C. In the sitting position with the back straight, the load is
increased 40 percent above relaxed standing.
D. With the subject standing and bending, the load
increases 50 percent.
E. Upright standing is equal to 100 percent of the relative
load.

Answer 90

A

Answer: C
Source: Hoppenfeld S. Physical Examination of the Spine
and Extremities. Appleton-Centry-Cross/Norwalk, CT p.
250.

Answer 91

A

Answer: C
Explanation:
First pass metabolism is the main factor that reduces the
amount of morphine that reaches the systemic circulation.
Source: Boswell MV, Board Review 2004

Answer 92

A

Answer: D
Explanation:
Rexed divided the spinal gray into ten laminae.
Laminae I through VI make up the dorsal horn.
Laminae VII through IX make up the ventral horn.
Lamina X is composed of a column of cells clustered
around the central canal of the cord.
Lamina I is the marginal layer, lamina II is the substantia
gelatinosa, and laminae II through V make
up the nucleus propius (magnocellular layer).

Answer 93

A

Answer: B
Explanation:
B. Previous dystonic reaction is a risk factor for acute
dystonic reaction, as are male sex, younger age, higher
doses of drugs and parenteral administration.
Atypical agents have less risk.
Source: Boswell MV, Board Review 2004

Answer 94

A

Answer: B

Source: Giordano J, Board Review 2003

Answer 95

A

Answer: D
Explanation:
Reference: Hardman, pp 1676-1678. Katzung, pp 990- 991.
Carbon monoxide is a common cause of accidental and
suicidal poisoning. Its affi nity for hemoglobin is 250 times
greater than that of O2. It therefore binds to hemoglobin
and reduces the O2 – carrying capacity of blood. The
symptoms of poisoning are due to tissue hypoxia; they
progress from headache and fatigue to confusion, syncope,
tachycardia, coma, convulsions, shock, respiratory
depression, and cardiovascular collapse. Carboxyhemoglobin
levels below 15% rarely produce symptoms;
above 40%, symptoms become severe. Treatment include
establishment of an airway, supportive therapy, and
administration of 100% O2 . Sulfur dioxide, ozone, and
nitrogen dioxide are mucous membrane and respiratory
irritants. Methane is a simple asphyxiant.
Source: Stern - 2004

Answer 96

A

Answer: C
Source: Hoppenfeld S. Physical Examination of the Spine
and Extremities. Appleton-Centry-Cross/Norwalk, CT p.
227.

Answer 97

A

Answer: A

Source: Giordano J, Board Review 2003

Answer 98

A

Answer: D
Explanation:
Phantom limb sensation is an almost universal occurrence
at some time during the fi rst month following surgery.
A. The strongest sensations come from body parts with the
highest brain cortical representation, such as the fi ngers
and toes. These highly innervated parts are also the areas
of most persistent phantom limb sensation.
B. Phantom sensations are either normal in character or as pleasant warmth and tingling. These are not painful.
C. The incidence of phantom limb sensation increases
with the age of the amputee. In children who have
amputation before 2 years of age, the incidence of
phantom limb sensation is 20%; the incidence of phantom
limb sensation is nearly 100% when amputation occurs
after 8 years of age.
D. The phantom limb may undergo the phenomenon
known as telescoping, in which the patient loses sensations
from the mid portion of the limb, with subsequent
shortening of the phantom. Telescoping is most common
in the upper extremity. During telescoping, the last body
parts to disappear are those with the highest
representation in the cortex, such as the thumb, index
fi nger, and big toe.
Only painless phantoms undergo telescoping, and
lengthening of the phantom may occur if the pain returns.
Thus, patients may feel that the amputated phantom limb
shortened.
E. Phantom limb sensations do not appear to require
peripheral nervous system input. Phantom limb
sensations may be an attempt to preserve the self image
and minimize distortion of the self image or may be a
permanent inherited neural memory of postural patterns.
Reference: Hord and Shannon. Chapter 16. Phantom Pain.
In: Practical Management of Pain, 3rd Edition.
Raj et al. Mosby, 2000, page 212-213.

Answer 99

A

Answer: E

Answer 100

A

Answer: A
Explanation:
Ref: Raj. Chapter 43. Thoracoabdominal Pain. In:
Practical Management of Pain. 3rd Edition. Raj et al,
Mosby, 2000. page 618.
Source: Day MR, Board Review 2003

Answer 101

A

Answer: D
Explanation:
Layer IV of the cerebral cortex, the internal granular layer,
is the principal receiving station of the cortex. The input
from the modality specifi c thalamic nuclei projects mainly
onto neurons in lamina IV, with some projections on
laminae III and IV. The nonspecifi c thalamocortical input
originating from nonspecifi c thalamic nuclei projects
diffusely on all laminae and establishes mostly
axodendritic types of synapses. (Afi fi and Bergman, 340-
343; Burt 451-452)
Source: Neurology Examination and Board Review By
Nizar Souayah, MD and Sami Khella, MD

Answer 102

A

Answer: A
Explanation:
(Guyton, pp 581-582.) The visual receptor cells, the rods
and cones, are depolarized in their nonstimulated state.
When exposed to light, they hyperpolarize.Light causes the
rods and cones to hyperpolarize by activating a G protein
called transducin, which leads to the closing of Na+ channels. Auditory receptors are depolarized by the fl ow of
K+ into the hair cells. Touch receptors are activated by
opening channels through which both Na+ and K+ can
fl ow. Depolarization is caused by the inward fl ow of Na+.
Smell and taste receptors are activated by G-protein
mediated mechanisms, some of which cause the receptor
cell to depolarize; other G proteins cause the release of
synaptic transmitter without any change in membrane
potential.

Answer 103

A

Answer: C

Source: Giordano J, Board Review 2003

Answer 104

A

Answer: B
Explanation:
Most uptake is by passive diffusion
Source: Boswell MV, Board Review 2004

Answer 105

A

Answer: B
Explanation:
(Braunwald, 15/e, pp 439–440, 2088. Junqueira, 9/e, pp
387-389.) Metabolism in the adrenal medulla is regulated
by glucocorticoids because they induce the enzyme
phenylethanolamine-N-methyltransferase, which catalyzes
the methylation of norepinephrine to epinephrine.Most of
the blood supply entering the medulla passes through the
cortex. Glucocorticoids synthesized in the zona fasciculata
of the adrenal are released into the sinusoids and enter the
medulla. The adrenal gland is not usually considered a
classic portal system although there are similarities.
Monoamine oxidase is a mitochondrial enzyme that
regulates the storage of catecholamines in peripheral
sympathetic nerve endings.
The adrenal gland functions as two separate glands. The
adrenal cortex is derived from mesoderm and the adrenal
medulla from neural crest. The blood supply to the adrenal
is derived from three adrenal arteries: (1) the superior
adrenal (suprarenal) from the inferior phrenic, (2) the
middle adrenal from the aorta, and (3) the inferior adrenal
from the renal artery.
Source: Klein RM and McKenzie JC 2002.

Answer 106

A

Answer: E
Explanation:
(Rhoades, pp 130-132.) A variety of physiological
functions, such as alertness (the sleep-wake cycle), body
temperature, and secretion of hormones, exhibits cyclic
activity that varies over a 24-h period of time. These
variations in activity are called circadian rhythms and are
controlled by the suprachiasmatic nucleus of the
hypothalamus. The paraventricular nucleus secretes
oxytocin and vasopressin, the ventromedial and lateral
nuclei control food intake, and the arcuate nucleus secretes
gonadotropin-releasing hormone.

Answer 107

A

Answer: B
Explanation:
Carlson, pp 352-359.
B. Testosterone administered postpubertally to castrated rats can restore aggressiveness to almost normal levels.
Similarly, neonatal female mice develop masculine
aggressive behavior on receiving androgens. Androgens
also promote aggression in humans.
C. Boys are more aggressive than girls at ages 3 to 10, as
has been demonstrated in studies of children.
Source: Ebert 2004

Answer 108

A

Answer: C

Source: (Raj, Pain Review, 2nd Ed., page 62)

Answer 109

A

Answer: C
Explanation:
The oculocardiac refl ex is defi ned as a slowing of the pulse
in response to traction on the extraocular muscles or from
pressure on the eye.
C. The afferent arc is by way of the ophthalmic branch of
the trigeminal nerve. Impulses travel through the reticular
network to the visceral motor nuclei of the vagus nerve,
which is the efferent limb of the refl ex to the heart.

Answer 110

A

Answer: D
Explanation:
Reference: Hardman, pp 192-193.
Nicotine is a depolarizing ganglionic blocking agent that
initially stimulates and then blocks nicotinic muscular
(NM) (skeletal muscle) and nicotinic neural (NN)
(parasympathetic ganglia) cholinergic receptors. Blockade
of the sympathetic division of the autonomic nervous
system (ANS) results in arteriolar vasodilation,
bradycardia, and hypotension. Blockade at the
neuromuscular junction leads to muscle weakness and
respiratory depression caused by interference with the
function of the diaphragm and intercostal muscles.
Atropine, a muscarinic receptor blocker, would be an
effective antagonist, as would neostigmine, a
cholinesterase inhibitor. Pilocarpine and isofl uorphate are
cholinomimetics and can be antagonized by atropine; the
effects of tubocurarine can be inhibited by neostigmine.
Diazoxide, a vasodilator, would cause tachycardia, rather
than bradycardia.
Source: Stern 2004

Answer 111

A

Answer: B
Explanation:
Acetylcholine and GABA bind ionic channel receptors,
insulin binds Tyrosine Kinase receptors and cortisol binds
nuclear receptors.
Source: Boswell MV, Board Review 2004

Answer 112

A

Answer: E
Explanation:
Norepinephrine is the neurotransmitter found in
postganglionic sympathetic (adrenergic) nerve endings.
The cells of the adrenal medulla are homologous to
postganglionic sympathetic neurons and contain both
epinephrine (80 percent) and norepinephrine (20
percent).
Source: Kahn and Desio

Answer 113

A

Answer: C
Explanation:
(Guyton, 9/e, pp 705-707.) The entire sympathetic nervous
system is activated when a person is frightened, preparing
the individual for fl ight or to fi ght. As part of this
preparation, the smooth muscle of the airways is relaxed,
increasing the airway diameter, making it easier for the
person to breathe. At the same time, heart rate and cardiac
output are increased, causing a rise in blood pressure, and
blood glucose concentrations are increased, making fuel
available for whatever choice is made.

Answer 114

A

Answer: B
Source: Hoppenfeld S. Physical Examination of the Spine
and Extremities. Appleton-Centry-Cross/Norwalk, CT

Answer 115

A

Answer: D
Source: Hoppenfeld S. Physical Examination of the Spine
and Extremities. Appleton-Centry-Cross/Norwalk, CT p.
227.

Answer 116

A

Answer: E
Source: Hoppenfeld, Stanley, Physical Examination of the
Spine and Extremities, Appleton-Centry-Cross/Norwalk,
CT p.256

Answer 117

A

Answer: D
Explanation:
(Guyton, pp 561-563.) Free nerve endings contain
receptors for temperature, pain, and touch. However, fi ne
touch, pressure, and vibration are detected by nerve
endings contained within specialized capsules that
transmit the stimulus to the sensory receptors. Muscle
length is encoded by the primary nerve endings of Ia fi bers
which are located on intrafusal fi bers within the muscle
spindle.

Answer 118

A

Answer: B
Explanation:
Reference: Katzung, pp 468-469:
A. Selegiline is an MAO-B inhibitor.
B. Bromocriptine mimics the action of dopamine in the
brain but is not as readily metabolized. It is especially
useful in parkinsonism that is unresponsive to L-dopa.
C. Apomorphine is also a dopamine receptor agonist, but
its side effects preclude its use for this purpose.
D. Amantadine is an antiviral agent that probably affects
the synthesis or uptake of dopamine.
E. Atropine is belladonna preparation.
Source: Stern - 2004

Answer 119

A

Answer: B
Explanation:
Neuroleptic malignant syndrome is an uncommon but
potentially fatal idiosyncratic reaction characterized by the
development of altered consciousness, hyperthermia,
autonomic dysfunction, and muscular rigidity on exposure
to neuroleptic (and probably other psychotropic)
medications. The pathophysiology of neuroleptic
malignant syndrome (NMS) is poorly understood. The
postulated mechanism involves blockade of central
dopamine receptors in the basal ganglia,the hypothalamus,
and peripherally in postganglionic sympathetic neurons
and smooth muscle
Source: Laxmaiah Manchikanti, MD

Answer 120

A

Answer: D
Explanation:
Reference: Hardman, p 617. Katzung, p 318.
Most NSAIDs inhibit both cyclooxygenase I and II,
resulting in decreased synthesis of prostaglandins,
prostacyclins, and thromboxanes.
Source: Stern - 2004

Answer 121

A

Answer: A
Explanation:
(Alberts, 3/e, pp 813-814, 834.) The cell cortex is an area
of the cell immediately underneath the plasma membrane
and is rich in actin, which is required for cytokinesis. This
region is important in maintaining the mechanical
strength of the cytoplasm of the cell. It is also essential for
cellular functions that require surface motility. These
functions include phagocytosis, cytokinesis, and cell
locomotion. Although movement of vesicles along
fi laments is regulated by minimyosins (myosin 1),
movement of vesicles and organelles is predominantly a
function of microtubules under the infl uence of the
unidirectional motors kinesin and dynein. The movements
of cilia and fl agella are driven by dynein and chromosomal
movements occur through microtubular kinetics.
Source: Klein RM and McKenzie JC 2002.

Answer 122

A

Answer: B
Explanation:
(Guyton, pp 689-691.) In a normal sleep cycle, a person
passes through the four stages of slow-wave sleep before
entering REM sleep. In narcolepsy, a person may pass
directly from the waking state to REM sleep. REM sleep is
characterized by irregular heart beats and respiration and
by periods of atonia (loss of muscle tone). It is also the
state of sleep in which dreaming occurs.

Answer 123

A

Answer: E
Explanation:
(Guyton, pp 552-555.) Activating nociceptors on the free
nerve endings of C fi bers produces ischemic pain. The C
fi bers synapse on interneurons located within the
substantia gelatinosa (laminas II and Ill)of the dorsal horn
of the spinal cord.The pathway conveying ischemic pain
to the brain is called the paleospinothalamic system. In
contrast, well-localized pain sensations are carried within
the neospinothalamic tract. Ischemic pain does not adapt to prolonged stimulation. Pain is produced by specifi c
nociceptors and not by intense stimulation of other
mechanical, thermal, or chemical receptors.

Answer 124

A

Answer: C
Explanation:
Reference:
Yaksh, Tony in Waldman, Interventional Pain
Management, Second Edition; Chapter 2, pp. 11-19.
Bonica’s Management of Pain, Third Edition, Chapter 3,
Spinal Mechanisms and their Modulation. pp. 87-90.
Evidence suggests that prolonged afferent stimulation by
nociceptive afferents triggers activation of NMDA (Nmethyl-
D-aspartate)receptors which in turn activate WDR
interneurons. The main neurotransmitter used by
nociceptive afferents synapsing within the dorsal horn is
glutamate, a versatile molecule that can bind to several
different classes of receptors. Those most involved in the
sensation of acute pain, AMPA (alpha-amino-3-hydroxy-
5-methyl-isoxazole-4-propionic-acid) receptors, are
always exposed on afferent nerve terminals. When AMPA
receptors are bound by glutamate, they open allowing Na+
ions to enter the cell. In contrast, receptors most involved
in the sensation of chronic pain, NMDA receptors, are not
functional unless there has been a persistent or large-scale
release of glutamate. Repeated activation of AMPA
receptors dislodges magnesium ions that act like stoppers
in transmembrane sodium and calcium channels of the
NMDA receptor complex. The conformational change in
the neuronal membrane opens the.NMDA receptor
channel to Ca++ ions which fl ow into the cell that makes
these receptors susceptible to stimulation is the fi rst step in
central hypersensitization (Figure 3) and may mark the
transition from acute to chronic pain.
The complex structure of the NMDA receptor makes it
susceptible to antagonism through a number of different
mechanisms. Ketamine and dextromethorphan create a
noncompetitive blockade of the ion channel within the
receptor complex.
Source: Schultz D, Board Review 2004

Answer 125

A

Answer: D
Explanation:
(Berne, 3/e, pp 118-121.) The Golgi tendon organ (GTO)
is located in the tendon of skeletal muscles and therefore is
in series with the muscle. Each time the muscle contracts,
the tension developed by the muscle causes the GTO to be
stretched. The Ib afferent fi bers, which innervate the GTO,
fi re in proportion to the amount of GTO stretch, and
therefore their fi ring rate provides the CNS with
information about the amount of tension developed by
the muscle. The muscle length and speed of shortening are
sent to the CNS by Ia afferents that innervate the intrafusal
fi bers within muscle spindles.

Answer 126

A

Answer: E
Explanation:
Valproate can also be useful in the treatment of AIDSrelated
mania. Valproic acid was approved by the FDA for
the treatment of acute mania. A therapeutic blood-level window of 45 to 125 mug/mL has been demonstrated to
correlate with antimanic response. Valproate might have
better effi cacy than lithium in the treatment of mixed
manic states, rapid cycling mania or other complex,
comorbid forms of bipolar disorder, and could synergize
with lithium to prevent relapses.
Source: Laxmaiah Manchikanti, MD

Answer 127

A

Answer: D
Explanation:
(Guyton, pp 711-714.)
A. Cerebrospinal fl uid (CSF), which is in osmotic
equilibrium with the extracellular fl uid of the b spinal
cord, is formed primarily in the choroid plexus by an
active process.
B.It circulates through the subarachnoid space between
mater and pia mater and is absorbed into the circulation
by the arachnoid villi.
C. The epidural space, which lies outside the dura mater,
may be used clinically for injection of anesthetics and
steroids.
D. CSF protein and glucose concentrations are much
lower than those of plasma. Changes in those
concentrations in the CSF are helpful in detecting
pathologic processes, such as tumor or infection, in which
the blood-brain barrier is disrupted.
E. CSF protein and glucose concentrations are much lower
than those of plasma. Changes in those concentrations in
the CSF are helpful in detecting pathologic processes, such
as tumor or infection, in which the blood-brain barrier is
disrupted

Answer 128

A

333. Answer: C
Explanation:
The loads on a L3 disc in a 70-kg person are as follows:
supine 30 kg;
standing 70 kg;
upright sitting without support 100 kg;
walking 85 kg;
bending sideways 95 kg;
jumping 110 kg;
bending forward 20° 120 kg;
lifting 20 kg with back straight and knees bent 210 kg;
lifting 20 kg with back bent and knees straight 340 kg
Source: Bonica

Answer 129

A

Answer: C
Explanation:
(Waxman, 24/e, p 256.)Information from baroreceptors in
the vascular wall passes via cardiac depressor nerves to
the glossopharyngeal nerve (CN IX). The cell bodies of
these neurons are located in the petrosal ganglion, and
their central processes terminate on second-order
interneurons in the nucleus of the solitary tract. These interneurons project to preganglionic parasympathetic
cardioinhibitory neurons in the nucleus ambiguus, which
reach ganglia on the surface of the heart via CN X (vagus
nerve) and branches of the cardiac plexus. CN V
(trigeminal) carries general somatic afferents from the
face and innervates muscles involved in mastication. CN
VII (facial) innervates the muscles of facial expression. CN
XI primarily innervates the trapezius and
sternocleidomastoid muscles.
Source: Klein RM and McKenzie JC 2002.

Answer 130

A

Answer: C
Explanation:
Reference: Katzung, pp 827-828.
Famciclovir is active against herpes simplex and varicella
zoster viruses. It is activated by a viral kinase to a
triphosphate. The triphosphate is a competitive substrate
for DNA polymerase.The incorporation of the famciclovir
triphosphate into viral DNA results in chain termination.
Source: Stern-2004

Answer 131

A

Answer: E
Source: (Raj, Pain Review, 2nd Ed. Page 62; Bonica, 3rd
Ed., page 1089)

Answer 132

A

Answer: E
Explanation:
The International Association for the Study of Pain has
defi ned several pain terms.
A. Spontaneous pain is an area or region that is anesthetic
is called anesthesia dolorosa
B. Hypersensitivity to a painful stimulus is called
hyperalgesia
C. Pain initiated or caused by a primary lesion or
dysfunction in the nervous system is called neuropathic
pain
D. An unpleasant abnormal sensation, whether
spontaneous or evoked is called dysesthesia
E. The perception of pain produced by stimuli that are
usually non-painful is called allodynia

Answer 133

A

Answer: D
Source: Raj P, Pain medicine - A comprehensive Review -
Second Edition

Answer 134

A

Answer: A
Explanation:
(Berne, 3/e, pp 155-158.) Each time a skeletal muscle fi ber
is stimulated by an alpha motoneuron, enough Ca2+ is
released from its sarcoplasmic reticulum (SR) to fully
activate all the troponin within the muscle. Therefore,
every cross bridge can contribute to the generation of
tension. However, the transmission of force from the cross
bridges to the tendon (or bone or measuring device) does
not occur until the series elastic component (SEC) of the
muscle is stretched. Repetitive fi ring increases the amount
of SEC stretch by maintaining cross-bridge cycling for a
longer period of time. This occurs because each time the
muscle is activated, the Ca2+ released from the SR
replaces the Ca2+ that has been resequestered since the last
stimulus. Repetitive fi ring increases neither the
concentration of Ca2+ within the myoplasm, the number
of myofi brils that are activated, nor the magnitude of the
end-plate potential. Because all of the cross bridges are
activated each time a skeletal muscle fi ber is activated, an
increase in Ca2+ concentration would have no effect on
muscle strength.

Answer 135

A

Answer: A
Explanation:
Reference: Hardman, p 495.
Explanation: Ergotamine has several pharmacologic
properties, including the blockade of a-adrenergic
receptors; however, its mechanism of action in treating
migraine headaches is primarily related to its agonistic
interaction with serotonin receptors (5-HT1D), resulting
in vasoconstriction. Although chronic treatment with this
nonsedative, nonanalgesic drug does not decrease the
frequency of or prevent migraine attacks, an oral dose of
ergotamine is the drug of choice for combating an
incipient attack of migraine headache, especially during
the prodromal stage.
Source: Stern - 2004

Answer 136

A

Answer: D
Source: Raj P, Pain medicine - A comprehensive Review -
Second Edition

Answer 137

A

Answer: B
Explanation:
(April, 3/e, p 429.) The cremaster refl ex is mediated by the
genitofemoral nerve. The femoral branch supplies the
afferent limb, and the genital branch supplies the efferent
limb. The ilioinguinal nerve provides sensory innervation
to the medial aspects of the thigh and the anterior aspects
of the mons or the base of the penis. The pudendal nerve
provides sensation to most of the skin of the perineum as
well as the motor supply to the perineal muscles. The
involuntary scrotal refl ex is based on temperature: warmth
causes relaxation of the dartos muscle, whereas cold
causes contraction.
Source: Klein RM and McKenzie JC 2002.

Answer 138

A

Answer: A (1, 2 & 3)
Explanation:
Pain assessment focuses upon quantifying primarily
qualitative variables that have unique subjective
experience for each patient. Attribution of such fi ndings to
particular pathologies is accomplished by relating clinical
fi ndings with patients’ subjective reports of the nature,
extent, and characteristics of their pain.
Source: Giordano J, Board Review 2005

Answer 139

A

Answer: B (1 & 3)
Explanation:
Disruption of glucose metabolism yields increased polyol
end products that are incorporated into neural
membranes and disrupt ionic gradients by interfering
with the Na-K ATPase function. This can lead to enhanced sodium fl ux
and membrane conductance, primarily in unmyelinated
nociceptive afferents (C-fi bers).
Source: Giordano J, Board Review 2005

Answer 140

A

Answer: D (4 Only)
Explanation:
(Kandel, pp 945-946.)
The physiologic responses to dreaming listed in the
question can easily be recorded in most people several
times each night. If awakened at such times, people usually
confi rm that they were dreaming.
A. The complex of physiologic signs (e.g.,
electroencephalographic desynchrony, rapid eye
movements, loss of muscle tonus, and cardiorespiratory
irregularities) is commonly referred to as REM sleep or
paradoxical sleep.
The term paradoxical sleep was applied originally
because the associated electroencephalographic pattern is
characteristic of the alert waking state even though the
dreaming person is, in fact, sound asleep.
Dreams occurring during NREM sleep are less easily
recalled, less vivid, less visual, less emotional, and more
pleasant.
Source: Ebert 2004

Answer 141

A

Answer: D (4 Only)

Source: Giordano J, Board Review 2003

Answer 142

A

Answer: D (4 Only)

Answer 143

A

Answer: D (4 Only)
Source: Hoppenfeld S. Physical Examination of the Spine
and Extremities. Appleton-Centry-Cross/Norwalk, CT
p.256.

Answer 144

A

Answer: B (1 & 3)
Explanation:
The successive excitation of nodes of Ranvier by an
impulse that jumps between successive nodes is termed
saltatory conduction.
1, 2. Action potentials are conducted from node to node by
myelinated nerves rather than continuously along the
entire fi ber as occurs in the unmyelinated nerve.
Saltatory conduction greatly increases the velocity of
nerve transmission in myelinated fi bers.
Saltatory conduction conserves energy because only the
nodes of Ranvier depolarize, resulting in lower loss of ions
than would otherwise occur.
Source: Kahn and Desio

Answer 145

A

Answer: A (1, 2, & 3)

Source: (Bonica, 3rd Ed., page 1010)

Answer 146

A

Answer: E (All)
Explanation:
There are signifi cant clinical differences between visceral
and cutaneous nociception.
Cutting and burning of mesentery, the uterine cervix, or
other visceral organs do not necessarily produce clinical
pain. However, traction, distention, or ischemia will
produce this type of pain.
The visceral nociceptors have wide receptive fi elds that
prevent accurate localization of visceral sensation, which
may explain the phenomenon of referred pain.
This pain is often diffuse and poorly localized and often
has a signifi cant autonomic component.
There are fewer nociceptors in the viscera than in the
skin, and these receptors may have a different activation
profi le.

Answer 147

A

Answer: E (All)
Explanation:
Reference:
Bonica’s Management of Pain, Third Edition, Chapter 3,
Spinal Mechanisms and their Modulation.
Anti-nociceptive pathways are activated when pain signals
ascending in the ventrolateral tracts reach the brain stem
and thalamus. Stimulation of the periventricular gray area
in the thalamus and the nucleus raphe magnus in the
brain stem stimulates release of endorphins and
enkephalins respectively. These ligands bind to their
respective receptors and initiate a series of physiochemical
changes that inhibit pain transmission in the spinal cord as
outlined in answers 1-4 above.
Since 70% of the endorphin and enkephalin receptors are
located in the presynaptic membranes of nociceptive
afferent terminals, most of the pain transmission is
stopped before it reaches the dorsal horn. The pain signals
that get through are further weakened by enkephalininduced
dynorphin activity in the spinal cord. Dynorphin
activation of kappa receptors on inhibitory interneurons
causes release of GABA which hyperpolarizes dorsal horn
cells and further inhibits pain transmission.
Source: Schultz D, Board Review 2004

Answer 148

A

Answer: C (2 & 4)

Answer 149

A

Answer: A ( 1, 2, & 3)
Explanation:
Reference:
Yaksh, Tony in Waldman, Interventional Pain
Management, Second Edition; Chapter 2, pp. 11-19.
Changes occur in peripheral tissue with injury and/or
with repetitive stimulation of C-fi bers. Tissue damage
causes increased capillary permeability with extravasation
of histamine, kinins, lipidic acids cytokines and a host of
inflammatory peptides.
Stimulation of C-fi bers results in release of these injury
products into tissues.
- The release of infl ammatory mediators into tissues
results in an infl ammatory milieu with the following
effects:
Local edema
Local erythema
Hyperalgesia
- This reaction is called “the triple response of Lewis.
It can be triggered by local axon refl exes from activation
of C-fi bers or from tissue injury.
The majority of C-fi bers, called “silent nociceptors”,
have little or no spontaneous activity and are activated
only by extremely intense physical stimuli.
- In the presence of infl ammation C-fi ber terminals
become sensitized and are activated by mild stimuli.
This creates a state referred to as hyperalgesia.
Infl ammatory mediators including substance P,
glutamate, VIP, somatostatin, CGRP and bombesin are
contained within the terminals of C-fi bers.
C-fi bers do not adapt to repetitive stimuli but instead
remain sensitized as long as the infl ammatory
environment is present.
Source: Schultz D, Board Review 2004

Answer 150

A

Answer: C (2 & 4)
Explanation:
Reference:
Yaksh, Tony in Waldman, Interventional Pain
Management, Second Edition; Chapter 2, pp. 11-19.
C-polymodal nociceptors are slow-conducting,
unmyelinated fi bers that are activated only by high
threshold stimulation.
- They are not activated by low threshold stimuli.
-They are called polymodal because they are activated by
a variety of noxious, nociceptive chemical, mechanical and
thermal stimuli.
* These neurons are pseudounipolar with cell bodies
residing in the dorsal root ganglion.
A short stem connects the cell body to the peripheral
axon which travels out to the peripheral tissues where it
arborizes into unspecialized free nerve endings.
Central axons synapse with dorsal horn neurons
primarily in Rexed’s lamina I (called the marginal zone), II
(called the substantia gelatinosa) and V (which along with
lamina III and IV, make up the nucleus proprius).
They are unipolar neurons with cell bodies that reside in
the dorsal root ganglion.
Source: Schultz D, Board Review 2004

Answer 151

A

Answer: C (2 & 4)
Explanation:
Endogenous opiods modulate nociception.All endogenous
opioids contain the amino acid sequence tyrosine-glycinephenylanine.
They are cleaved from three precursor
molecules: proenkephalin A, proopiomelanocortin, and
prodynorphin (proenkephalin B).
Proenkephalin A is cleaved to form met- and leuenkephalins.
Prodynorphin is cleaved to form dynorphin and alphaneoendorphin,
which are not potent analgesics. They are
found in the same distribution as the enkephalins. Their
function has not been fully determined.
Enkephalins are found in highest concentration in the
GI tract, sympathetic nervous system, adrenal medulla,
periaqueductal gray, the rostroventral medulla, and
Rexed’s laminae I, II, V, and X.
Beta-endorphin, which is derived from
proopiomelanocortin, is released from the pituitary gland
along with ACTH. It is the most potent opiod and is found
in high concentrations in the hypothalamus,
periaqueductal gray, and locus ceruleus.

Answer 152

A

Answer: E (All)
Explanation:
Peripheral nerve axons are always enveloped by a
Schwann cell.
- The myelinated nerves may be enveloped many times by
the same Schwann cell.
Transmission of nerve impulses (i.e., action potentials)
along nonmyelinated nerves occurs in a continuous
fashion, whereas transmission along myelinated nerves
occurs by saltatory conduction from one node of Ranvier
to the next.
- Myelination speeds transmission of neurological
impulses; it also renders nerves more susceptible to local
anesthetic blockade.
An action potential is associated with an inward fl ux of
sodium that occurs after a certain membrane threshold
has been exceeded.
Propagation of an action potential along myelinated
nerve axons occurs by saltatory conduction via the nodes
of Ranvier.
Ref.: Hall and Chantigan.

Answer 153

A

Answer: C (2 & 4)
Explanation:
The parasympathetic nervous system consists of cranial
and sacral portions.
The cell bodies of preganglionic parasympathetic fi bers are
located in cranial nerve nuclei of the brainstem. The long
preganglionic fi bers of the oculomotor, facial, and
glossopharyngeal nerves synapse with short postganglionic fi bers of the ciliary, sphenopalatine, and
otic ganglia. The very long preganglionic fi bers of the
vagus synapse in intramural ganglia of the heart, lungs,
and gastrointestinal tract.
Preganglionic neurons of the sacral portion of the
parasympathetic nervous system have cell bodies located
inthe intermediolateral gray of the second, third, and
fourth sacral cord segments.
Source: Kahn and Desio

Answer 154

A

Answer: A (1, 2, & 3 )
Explanation:
- Extrogenously administered opioids exert their
analgesic effects by acting directly on the CNS.
- The major anatomic areas involved in opioid-mediated
analgesia include the periventricular and periaqueductal
gray matter and the rostroventral medulla.

Answer 155

A

Answer: B (1 & 3)
Explanation:
The rostroventral medulla is rich in serotonergic
neurons that project to the spinal cord.
Stimulation of neurons in the rostroventral medulla
with serotonergic terminals in the dorsal horn inhibits
nociceptive neurons in laminae I and II.
Serotonin is a neurotransmitter in descending
antinociceptive pathways.
Application of serotonin to the spinal cord inhibits
discharge of spinothalamic tract neurons and relieves pain.

Answer 156

A

Answer: E (All)
Explanation:
The reticular formation participates in the regulation of
motor, sensory, and autonomic functions.
The reticular formation consists of a number of vaguely
defi ned nuclei situated in the core of the brainstem and
extending throughout its rostrocaudal aspect.
Many reticular neurons respond to noxious stimulation,
and many respond exclusively to specifi c noxious
modalities.
The reticular formation is thought to participate in the
affective/motivational component of pain and in the
integration of pain with autonomic and motor behavior.

Answer 157

A

Answer: E (All)
Explanation:
The major ascending nociceptive tract in the anterolateral
quadrant (ALQ) is the spinothalamic tract (STT). Other
tracts of the ALQ that are thought to be involved in pain
perception are:
- the spinoreticular tract (SRT),
the spinomesencephalic tract (SMT),
- the dorsal column postsynaptic spinomedullary system,
and
- the propriospinal multisynaptic ascending system.
Source: Kahn and Desio

Answer 158

A

Answer: C (2 & 4)
Explanation:
Laminae I, II, and V are the major areas for convergence
of nociceptive transmission at the spinal cord.
Cells from these areas project to the thalamus, and
cutting this projection abolishes cutaneous pain.
Stimulating the projections of laminae I and II produces
pain.
Discharge of these cells increases with increasing
noxious stimulation.
- In response to a brief noxious stimulus, laminae I and V
neurons have early and late discharges, analogous to fi rst
and second pain.

Answer 159

A

Answer: E (All)
Explanation:
Three classes of cells are found in the dorsal horn:
Excitatory interneurons relay nociceptive transmission
to projection cells, to other interneurons, or to motor cells
concerned with refl exes
Inhibitory interneurons modulate nociceptive
tranmission.
Projection cells relay information to rostral center
Other cells in the dorsal horn receive additional input
from nonnociceptive afferents. These cells are called wide
dynamic range (WDR) neurons and respond to a wide
range of stimuli from low to high intensity.

Answer 160

A

Answer: C (2 & 4)
Explanation:
-Bradykinin is a 9-amino acid peptide produced at sites of
tissue injury by enzymatic action.
- Bradykinin produces pain in humans at concentrations
equivalent to those found in injured tissue.
- Binding sites for bradykinin are found on sensory fi bers
and in the dorsal horn.
Bradykinin increases vascular permeability.
Bradykinin has binding sites in the dorsal horn.
Bradykinin enhances leukocyte chemotaxis, and
sensitizes nociceptors.
Bradykinin is produced as sites of tissue injury.
Source: Kahn and Desio

Answer 161

A

Answer: B (1 & 3)
Explanation:
The efferent limb is mediated by the facial nerve (7th
cranial), which conveys the impulse to the orbicularis
oculi.
The afferent limb of the refl ex is the ophthalmic
division of the trigeminal nerve (5th cranial).

Answer 162

A

Answer: A (1, 2, & 3)

Source: Rozen. Pain Practice: SEP 2001

Answer 163

A

Answer: A ( 1, 2, & 3)
Explanation:
Reference:
Bonica’s Management of Pain, Third Edition, Chapter 3,
Peripheral Pain Mechanisms and Nociceptor Plasticity. pp.
37-38
In many respects, the anatomy, physiology and
biochemistry of cranial nociception is homologous to pain
pathways in the rest of the body. Transmission of pain in
the anterior two thirds of the head occurs primarily
through the trigeminal system. The trigeminal ganglion
houses the cell bodies of pseudounipolar A-delta and Cfi
ber axons which exit the ganglion and innervate the
anterior head, traveling outward within the three divisions
of the trigeminal system: the ophthalmic (V1), maxillary
(V2) and mandibular (V3) nerves.
The central processes of these axons exit the ganglion
and travel into the subnucleus caudalis portion of the
trigeminocervical nucleus (spinal nucleus V) where they
synapse with interneurons.
The cell bodies of the nociceptive afferent fi bers
transmitting her pain reside in the trigeminal ganglion.
V2 is most likely involved in pain transmission.
Pain sensation in the posterior upper neck and occipital
region is transmitted by the upper cervical nerve roots
especially C2.
- The C2 dorsal root ganglion contains the cell bodies of
nociceptive afferents, the central processes of which
synapse in the subnucleus caudalis on the same
interneuron pool as the trigeminal nociceptive fi bers.
- This explains why anterior face pain transmitted via the
trigeminal system can cause occipital referred pain and
also why posterior neck pain can sometimes be referred to
the face.
Source: Schultz D, Board Review 2004

Answer 164

A

Answer: A (1, 2, & 3 )
Explanation:
Acetylcholine is released at all preganglionic nerve
endings (both sympathetic and parasympathetic)
Acetylcholine is released at preganglionic sympathetic nerve endings.
Acetylcholine is released at postganglionic
parasympathetic nerve endings.
- Sympathetic postganglionic innervation to sweat
glands is also cholinergic.
Norepinephrine is the neurotransmitter found in
postganglionic sympathetic nerve endings.

Answer 165

A

Answer: B (1 & 3)
Explanation:
There are two types of A-delta fi bers: Those that subtend
high threshold tensile and/or compressive mechanical
stimuli and those that transduce noxious cold ( 45o C). A third population the mixed
mechanothermal nociceptor is capable of responding to
both types of noxious input.
Medium threshold mechanical input is subserved by Abeta
fi bers.
Polymodal/ chemical high threshold input is subserved by
C-fi bers.
Source: Giordano J, Board Review 2005

Answer 166

A

Answer: D (4 Only)
Explanation:
1, 2. Activation of beta receptors results in relaxation of
bronchial muscles and increases in cardiac rate and force
of contraction.
Activation of alpha receptors results in increased
peripheral vascular resistance, mydriasis, and contraction
of pilomotor muscles.
The alpha-2 receptors are found in both presynaptic and
postsynaptic locations. Stimulation of presynaptic alpha-2
receptors inhibits norepinephrine release, serving as a
negative feedback mechanism.

Answer 167

A

Answer: E (All)
Explanation:
Type-II pain is a multi-dimensional neural event that is
reliant upon peripheral and central sensitizing effects and
the summative physiologic characteristics of both primary
afferent and second-order neurons.
Source: Giordano J, Board Review 2005

Answer 168

A

Answer: B (1 & 3)
Explanation:
Neurons are highly responsive to changes in the pH of the
surrounding interstitial fl uids.
Alkalosis enhances neuronal excitability as does
hyperventilation.
Acidosis depresses neuron excitability.
Inhaled anesthetics suppress neuronal excitability.
Hyperventilation causes alkalosis and enhances
neuronal excitability.
Lack of oxygen can cause total inexcitability of neurons within 3 to 5 s.

Answer 169

A

Answer: C (2 & 4)
Explanation:
1, 3. Structures insensitive to pain include the intracranial
structures of the parenchyma of the brain, ependyma,
choroids plexus, pia mater, arachnoid membrane, and
parts of the dura mater, as well as the extracranial
skull (except for the periosteum, which is slightly painsensitive).
2, 4. Pain-sensitive structures include such intracranial
structures as the cranial sinuses and afferent veins, the
arteries of the dura mater, the arteries of the base of the
brain and their major branches, and parts of the dura
mater in the vicinity of large vessels.
Extracranial structures that are pain-sensitive include the
skin, scalp, fascia, muscles, mucosa, arteries, and veins.
- The trigeminal, facial, vagal, glossopharyngeal, and
second and third cranial nerves are also sensitive.
Source: Kahn and Desio

Answer 170

A

Answer: E (All)
Explanation:
All peripheral nerve injury appears to have a central
effect. After peripheral nerve injury, the primary afferents
arborize into new areas of the dorsal horn.
2.In addition, they stop making substance P and CGRP
and start making neuropeptide y, galanin, and VIP.
There is upregulation of the early immediate gene CFos,
which stimulates production of Fos protein.
There is increased production of dynorphin by secondorder
neurons.
Source: Kahn CH, DeSio JM. PreTest Self Assessment and
Review. Pain Management. New York, McGraw-Hill, Inc.,
1996.

Answer 171

A

Answer: B (1 & 3)
Explanation:
Cell bodies of somatic motor nerves lie in the anterior
horn of the spinal cord or in motor nuclei of cranial
nerves.
Those of somatic sensory neurons reside in dorsal root
ganglia, which are located in the intervertebral foramina.
Sensory nerves subserving visceral sensation also have
their cell bodies in dorsal root ganglia, through their
axonal processes may travel with autonomic nerves to the
periphery.

Answer 172

A

Answer: E (All)
Explanation:
Reference:
Bonica’s Management of Pain, Third Edition, Chapter 4, Spinal Mechanisms and their Modulation pp. 73-85
Wide dynamic range (WDR) neurons are found mainly
in dorsal horn lamina V (nucleus proprius).
They are interneurons that have large cutaneuous as well
as visceral receptive fi elds.
- Single WDR neurons receive diverse input from various
visceral and cutaneous tissues and are commonly called
“convergence neurons”. They are thought to be responsible
for the spinal component of referred pain.
Low frequency, repetitive stimulation of C-fi bers
produces a gradual increase in the frequency of WDR
neuron activity until the neuron is in a state of virtually
continuous discharge called “wind-up”.
They are activated by innocuous as well as noxious
stimuli. Light innocuous touch evokes activity that
increases with the intensity of pressure or pinch into the
noxious range.
Source: Schultz D, Board Review 2004

Answer 173

A

Answer: C (2 & 4)
Explanation:
Serotonin has been implicated as an algogenic
substance.
It is released by platelets in response to plateletactivating
factor, a substance released by degranulating
mast cells.
Serotonin causes pain directly and by potentiation of
the nociceptive effect of bradykinin.
Serotonin receptors are found on peripheral nerves, and
antagonists will block the nociceptive effects of serotonin

Answer 174

A

Answer: E (All)

Answer 175

A

Answer: B (1 & 3)
Explanation:
Visceral afferents generally travel with sympathetic
fi bers.
They are not autonomic fi bers.
Visceral afferents generally have large, confl uent
receptive fi elds.
They can be sensitized in response to certain conditions
(infl ammation).
Source: Kahn and Desio

Answer 176

A

Answer: A (1, 2, & 3 )
Explanation:
A neuron consists of a cell body (soma)
A neuron contains a dendrites
- Dendrites are extensions of the cell body.
The axon of one neuron terminates near the cell body or
dendrites of another neuron.
A synapse is the junction between neurons and serves as
an important control mechanism for transmission of
impulses.

Answer 177

A

Answer: B (1 & 3)
Explanation:
Type I pain is produced in response to defi ned organic
insult/ trauma as a reaction to primary processes that
stimulate the nociceptive neuraxis; it is physiologic.
Type III pain represents a discrete pathologic process in
which there is peripheral and/ or central sensitization of a
potential variety of substrates within the nociceptive
neuraxis; frequently, pain is produced or persists in the
absence of defi nable organic lesion. It is a neurogenic,
pathologic process.
Source: Giordano J, Board Review 2005

Answer 178

A

Answer: A (1, 2 & 3)
Explanation:
Numerous clinical tests are useful in assessing the
emotional, conscious, and behavioral correlates of
cognition that result from pain. The BDI, BPI, and MPQ
have all been shown to have high construct/ content
validity and replicability, and are reliable evaluative tools
in clinical pain assessment.
The MMPI is frequently employed to assess pathologic or
deviant characteristics of personality in psychiatric and/or
clinical psychological circumstances. This test is
sometimes advocated by third party remunerators to
determine co-morbid confounding factors to patients’
response/ recovery potential to invasive pain management
interventions (such as in-dwelling morphine pumps
and/or DCS); its validity in such circumstances is
debatable.
Source: Giordano J, Board Review 2005

Answer 179

A

Answer: B (1 & 3)
Explanation:
Opioids (endorphins and enkephalins) released from
opioid neurons of the PAG act at mu and delta receptors
to hyperpolarize tonically inhibitory GABAergic
interneurons that reduce/ suppress fi ring of
monoaminergic descending noxious inhibitory control
systems of the brainstem. Such disinhibition increases
bulbospinal modulation of noxious afferent input and is a
fundamental component of centrifugal analgesia.
Source: Giordano J, Board Review 2005

Answer 180

A

Answer: C (2 & 4)
Explanation:
- Muscarinic receptors are located in all effector cells
stimulated by postganglionic parasympathetic neurons as
well as postganglionic cholinergic sympathetic neurons.
- Nicotinic receptors are located in the ganglionic
synapses between pre- and postganglionic neurons of the sympathetic and parasympathetic nervous system.
Source: Kahn and Desio

Answer 181

A

Answer: A (1, 2, & 3)

Source: Nader and Candido Pain Practice. June 2001

Answer 182

A

Answer: E (All)
Explanation:
Nociception involves four physiologic processes.
Transmission is the propagation of impulses
throughout the sensory nervous system.
Modulation is the process whereby nociceptive
transmission is modifi ed through a number of neural
infl uences
Perception is the fi nal process in which all aspects of
pain are experienced.
Transduction is the process whereby noxious stimuli
are translated into electrical activity at the sensory endings
of nerves.

Answer 183

A

Answer: A ( 1, 2, & 3)
Explanation:
1, 2. The innervation for cremaster refl ex is through the L1
and L2 segments (ilionguinal and genitofemoral
nerves).
Stroking the skin on the upper, inner aspect of the thigh
elicits the cremaster refl ex. The response consists of a
contraction of the cremasteric muscle, with ipsilateral
elevation of the testicle

Answer 184

A

Answer: E (All)
Explanation:
Histamine is released from injured cells and from mast
cells stimulated by substance P.
It causes activation of nociceptors, vasodilation, and
edema.

Answer 185

A

Answer: E (All)
Explanation:
Dextromethorphan, the D isomer of the codeine analog of
levorphanol, has been used clinically as a central
antitussive drug for more than 40 years. It has weak
affi nity for the μ-opioid receptor and has a sedative effect.
Dextromethorphan and its metabolite, dextrorphan, have
non-competitive NMDA receptor antagonist properties.
The pharmacology of central sensitization has shown
that the N-methyl-d-aspartate (NMDA) receptors are
involved.
Interventions that prevent the establishment of central
sensitization are considered as preemptive analgesia
Co-administration of NMDA receptor antagonist with
an opioid may prevent central sensitization
Co-administration of NMDA receptor antagonist with
an opioid may enhance opioid-induced anti-nociception
and may prevent tolerance to opioid analgesia

Answer 186

A

Answer: E (All)

Source: Helms. Acupuncture Energetics. 1995

Answer 187

A

Answer: B (1 & 3)

Answer 188

A

Answer: C (2 & 4)
Explanation:
The orientation of the facets determines the direction of
motion of that spinal segment.
Facet joints comprise two arthrodial joints lined with
synovium and lubricated with synovial fl uid.
In the thoracic spine, the facets are convex-concave and
lie in the horizontal plane, permitting lateral fl exing, side
bending, and rotation about a vertical line.
In the upper lumbar spine, the facets lie in a vertical
sagittal plane and permit fl exion and extension but
prevent lateral fl exion or bending in the lordotic curve.

Answer 189

A

Answer: D (4 Only)
Explanation:
Withdrawal fl exor refl exes are most often elicited by a
painful stimulus.
Pathways for eliciting the withdrawal refl ex do not pass
directly to the anterior motor neurons but instead pass
fi rst through several interneurons.
Associated with withdrawal of the stimulated limb is
extension of the opposite limb, which occurs 0.2 to o,5 s
later and serves to push the body away from the object
causing the painful stimulus.
Withdrawal refl exes are associated with extension of the
opposite limb.
Source: Kahn and Desio

Answer 190

A

Answer: A (1, 2, & 3 )
Explanation:
- The abdominal wall is divided into nine regions by four
imaginary lines of which two pass horizontally around the
body and two vertically. The nine regions include the right
and left hypochondriac, lumbar, and iliac areas and in the
midline the epigastric, umbilical, and hypogastric areas.
- The upper horizontal line (transpyloric plane) lies
between the suprasternal notch and the symphysis pubis.
- The lower line (transtubercular plane) lies at the top of
the crests of the iliac bones.
- Two vertical lines (one on each side of the body) descend
from the cartilages of the 8th rib to the center of the
inguinal ligament.
Left iliac and right iliac
Right and left hypochondriac
Midline epigastric
There is no hypergastric quadrant(s)

Answer 191

A

Answer: E (All)

Source: (Bonica, 3rd Ed., page 1566)

Answer 192

A

Answer: A ( 1, 2, & 3)
Explanation:
Reference:
Yaksh, Tony in Waldman, Interventional Pain
Management, Second Edition; Chapter 2, pp. 26-27.
Bonica’s Management of Pain, Third Edition, Chapter 3,
Spinal Mechanisms and their Modulation.
The hallmarks of neuropathic pain are chronic allodynia
and hyperalgesia. Allodynia is defi ned as pain resulting
from a stimulus that ordinarily does not elicit a painful
response (eg. light touch). Hyperalgesia is defi ned as an
increased sensitivity to a normally painful stimulus. There
are two types of hyperalgesia which are triggered by
different neural mechanisms.
Primary hyperalgesia occurs at the site of injury, for
instance within the confi ned area of capsaicin application.
- It refl ects sensitization of peripheral nociceptors and
involves altered physiology and pharmacology of the
sensory nociceptive terminals to produce a leftward shift
in the stimulus and response curve for activation.
- It is triggered by infl ammatory mediators, persisting
noxious stimuli, or both, and is characterized by lowered
threshold, increased rate of action potentials, spontaneous
activity and increased pain sensation to supra-threshold
stimuli.
Secondary hyperalgesia occurs in the area surrounding
the area of injured tissue and refl ects the process of central
sensitization that forms the basis for many types of
pathological pain.
Secondary hyperalgesia is driven mainly by increased
excitability of central neurons via activated NMDA
receptors.
Intrathecal application of NMDA receptor antagonists
do not attenuate the initial hyperalgesia response to
capsaicin application (primary hyperalgesia) but the
secondary delayed pain and sensitivity outside the region
of injured tissue (secondary hyperalgesia) is substantially
reduced if the NMDA antagonist is administered prior to
the initial pain stimulus.
Source: Schultz D, Board Review 2004

Answer 193

A

Answer: A (1, 2, & 3 )
Explanation:
Substance P is synthesized in the neuronal cell bodies in
the dorsal root ganglia.
Substance is released on stimulation of primary afferent
nociceptors and causes vasodilation and edema.
It is transported to peripheral and central terminals,
where it is stored in vesicles.
Substance P causes release of histamine from mast cells,
resulting in further vasodilation and edema.

Answer 194

A

Answer: E (All)
Explanation:
The most common nociceptor appears to be the
cutaneous mechanothermal nociceptor, which responds to
noxious mechanical and thermal stimuli.
The most common nociceptor in humans appears to be
the C-fi ber mechanothermal nociceptor, which responds
to mechanical, thermal, and chemical stimuli.
Cutaneous mechanothermal nociceptors activate both
A-delta and C fi bers.
Modality-specifi c (e.g., heat) nociceptors exist, but the
majority appear to respond to more than one noxious
stimulus.
They may also be referred to as C-polymodal
nociceptors

Answer 195

A

Answer: D (4 Only)

Answer 196

A

Answer: A
Explanation:
The diagnosis of manic episodes is established by the
presence of irritability or euphoria associated with 3
(euphoria) or 4 (irritability) of the 7 cardial symptoms of
mania. The cardial symptoms of mania are distractibility,
insomnia, grandiosity, fl ight of ideas, increased activities,
pressured speech, and thoughtlessness.
Source: Laxmaiah Manchikanti, MD

Answer 197

A

Answer: A (1, 2, & 3)
Source: Hoppenfeld S. Physical Examination of the Spine
and Extremities. Appleton-Centry-Cross/Norwalk, CT
p.189.

Answer 198

A

Answer: B (1 & 3)

Answer 199

A

Answer: A (1, 2, & 3 )
Explanation:
Spinal analgesia is mediated by the delta and kappa
receptors.
Delta-receptor activation results in spinal analgesia
without sedation or respiratory depression.
The delta-receptor ligand(D-ala, D-leu enkephalin;DADL)
has been found to be fi ve times more potent than morphine ( a mu-receptor agonist) when given
intrathecally.
Kappa-receptor activation results in spinal analgesia and
sedation without respiratory depression.
Activation of mu-1 receptors has analgesic effects
(mostly supraspinal, though some mu-1 receptors are
found in the spinal cord).
Activation of mu-2 receptors produces respiratory
depression, bradycardia, and depression of GI motility.

Answer 200

A

Answer: B (1 & 3)
Explanation:
As small afferent axons (C and A-delta) enter the spinal
cord, they are displaced lateral to the A-beta fi bers (from
muscle spindles and proprioceptive afferents) and
trifurcate in the tract of Lissauer at the level of entry and
with projections rostrally and caudally.
Unmyelinated C fi bers arising from the dorsal root
ganglion cells also send projections into the ventral roots,
which accounts for pain sensation that can occur with
ventral root stimulation.

Answer 201

A

Answer: E (All)
Explanation:
Below the level of the vocal cords the larynx and trachea
are innervated by the recurrent laryngeal branch of the
vagus nerve.
The recurrent laryngeal nerve not only provides sensation
to the structures below the level of the cords, it also
supplies motor function to all the intrinsic muscles of the
larynx except the cricothyroid muscle.
Bilateral blockade of the recurrent laryngeal nerve will
result in loss of phonation as well as an inability to close
the glottis.

Answer 202

A

Answer: B (1 & 3)
Explanation:
A-alpha fi bers provide large motor function and
proprioception and are responsible for refl ex activity.
A-alpha, -beta, and –gamma myelinated fi bers are 20 m in
diameter. They have a conduction velocity of 100 m/s.
A-beta fi bers are responsible for small motor function,
touch, and pressure.
A-gamma fi bers provide muscle tone via innervation of
the muscle spindle fi bers.
A-delta fi bers are myelinated fi bers of 4 m in diameter that
conduct impulses at 5m/s. They transmit temperature
sensation, sharp pain, and possibly touch.
C fi bers are unmyelinated fi bers 0.5 to 1.0m with a conduction velocity of 1.2m/s. They transmit dull pain,
temperature, and touch.

Answer 203

A

Answer: B (1 & 3)
Explanation:
The stellate ganglion is another term for the inferior
cervical ganglion, which lies behind the subclavian artery,
near the origin of the vertebral artery at the level of the
seventh cervical vertebra. It is sometimes fused with the
fi rst thoracic ganglion.
2, 4. Autonomic ganglia include the ciliary, sphenopalatine,
otic, and submaxillary ganglia, which are situated in a
relation to the respective cranial nerves (III, VII, and IX).
Each ganglion receives sympathetic postganglionic
fi bers, parasympathetic preganglionic fi bers, and sensory
fi bers.
The superior, middle, intermediate, and inferior ganglia
compose the sympathetic chain within the cervical region.
Source: Kahn and Desio

Answer 204

A

Answer: D (4 Only)
Explanation:
1, 2, 3. A ganglion refers to a site of synaptic connections
specifi c to the sympathetic or parasympathetic systems.
Plexus refers to a number of ganglia and axons
(sympathetic and parasympathetic, as well as visceral
afferent) converging in a well-defi ned anatomic location.

Answer 205

A

Answer: E (All)

Answer 206

A

Answer: C-2and4
Explanation:
Reference
Bonica’s Management of Pain, 3rd Ed: Ch 3. Peripheral
pain mechanisms and nociceptive plasiticity. Also Bonica’s
Management of Pain, 3rd Ed: Ch4. Spinal mechanisms and
modulation. Chronic neuropathic pain can induce plastic,
genotypic changes in a-beta mechanoreceptors that
promote phenotypic remodeling of a-beta terminal
projections within the superfi cial dorsal horn. A-beta
projections “migrate” into lamina II to activate nociceptive
specifi c and wide dynamic range neurons to produce
mechanical hyperalgesia. Increased penetrance to lamina
VII can directly engage sympathetic preganglionic neurons
of the intramedial lateral zone to increase sympathetic
outfl ow and contribute to the cyclisity of SMP. Such
remodeling in the synaptic fi elds of a-beta
mechanoreceptors decreased input to second order wide
dynamic mechanospecifi c neurons that comprise the
dorsal column/medial lemniscal pathway. This can lead to
a change in mechanosensation and decrease in dorsal
columnar inhibition of even mild noxious input.
Source: Giordano J, Board Review 2005

Answer 207

A

Answer: E- all
Explanation:
Reference
Lecture notes. Sympathetically mediated pain may be
diffi cult to evaluate based solely upon results of single
technologic diagnostic tests. Characteristically, thermal
metric evaluation is coupled with quantitative sensory
testing, axon refl ex evaluation, Doppler, fl owmetry and
correlated with patient narrative, history and physical
exam. The need for narrative/history emphasizes the
discrepant characteristics of qualitative (subjective)
aspects of SMP and quantitative variables.
Source: Giordano J, Board Review 2005

Answer 208

A

Answer: B-1and3
Explanation:
Reference:
Bonica’s Management of Pain, 3rd Ed: Ch 3. Peripheral
pain mechanisms and nociceptive plasiticity. Initial tissue
insult can induce the arachidonic acid cascade, to produce
cycloxygenase derived prostaglandin E2 that activates
peripheral C-fi bers via effects at a prostenoid receptor on
C-fi ber terminals. The activation of C-fi bers can cause
antidromic release of Substance P which acts as a potent
vasodilator thereby inducing extravasation of pronocicepted
mediators and subsequent
reactivation/sensitization of C-fi bers. Prolonged C-fi ber
activation/sensitization can produce primary hyperalgesia.
Continued C-fi ber-evoked activation of second order
spinal afferents can produce central (secondary)
hyperalgesia.
Source: Giordano J, Board Review 2005

Answer 209

A

Answer: A-1, 2 and 3
Explanation:
Reference:
Bonica’s Management of Pain, 3rd Ed: Ch4. Spinal
mechanisms and modulation. Yaksh T In: Waldman,
interventional pain management, 2nd Ed, Ch. 2. Acute
sympathetic activation is a principle substrate of stress
induced analgesia (SIA). SIA involves both the release of
adrenal opioids as well as engagement of multiple nonopioid
peptide and non-peptide brain mechanisms
that can produce peripheral and central (“attentional”
analgesia against nociceptive pain. Long term stress and
chronic sympathetic activatin is pain promotional and
certainly not modulatory of neuropathic pain.
Source: Giordano J, Board Review 2005

Answer 210

A

Answer: B (1 & 3)
Explanation:
Reference:
Yaksh, Tony in Waldman, Interventional Pain
Management, Second Edition; Chapter 2,
Bonica’s Management of Pain, Third Edition, Chapter 4,
Spinal Mechanisms and their Modulation
If the spinal cord is completely transected, all sensory and
motor functions distal to the transaction are blocked.If the
spinal cord is transected only on a single side, the Brown-
Sequard syndrome occurs:
- Loss of motor function ipsilateral to the lesion at all
levels below the lesion.
Pain and temperature sensation is lost on the contralateral
side 2 to 6 dermatomes below the lesion.
- Light touch and tactile sensation is lost ipsilateral to the
lesion at all levels below the lesion.
This pattern of loss occurs because:
- Pain and temperature sensation is a crossed neural
pathway. Pain and temperature fi bers enter the dorsal horn
through the dorsal root, ascend and descend for several
segments in Lissauer’s tract in the superfi cial cap of the
dorsal horn, then enter the dorsal horn, synapse with
interneurons and move across the cord in the anterior
commissure to the contralateral side where they ascend in
the ventrolateral columns (especially the spinothalamic
tract). Transection of the ventrolateral tract will transect
pain and temperature fi bers which originate on the
contralateral side of the cord several segments below the
lesion.
- Motor function is not crossed. Motor fi bers stay
ipsilateral at the cord level so transaction of the one side of
the cord will cause ipsilateral motor loss below the lesion.
- Light touch is transmitted by A-beta fi bers which ascend
ipsilaterally in the dorsal columns. Hemisection of the
cord will also cause ipsilateral light touch loss below the
lesion.
With ventrolateral cordotomy, the target is isolated to
the spinothalamic tract.
- This tract primarily transmits ascending pain and
temperature fi bers which originate contralaterally.
- The expected result would be loss of pain and
temperature sensation several segments below the lesion
on the contralateral side with no effect on motor strength
or tactile sensation.
Light touch and tactile sensation is lost ipsilateral to the
lesion at all levels below the lesion.
Temperature (hot and cold) sensation would be lost on
the contralateral side several segments below the lesion.
The pain relieving effects of ventrolateral cordotomy
are typically incomplete because some nociceptive fi bers
do not cross and ascend ipsilaterally. The effects are
typically short-lived with anomalous recovery of pain after
3-12 months. This suggests that relevance of other pain
pathways outside of the crossed, spinothalamic path.
Source: Schultz D, Board Review 2004

Answer 211

A

Answer: E (All)

Source: Nader and Candido – Pain Practice. June 2001

Answer 212

A

Answer: E (All)
Explanation:
The fi ve basic types of sensory receptors are:
Mechanoreceptors, which detect tissue deformation
Electromagnetic receptors, which detect light on the
retina
Thermoreceptors for cold and warmth
Nociceptors, which detect painful stimuli due to
physical or chemical damage in tissue
The fi fth type, chemoreceptors, which detect taste, smell,
arterial partial pressure of oxygen and carbon dioxide, and
serum osmolarity.

Answer 213

A

Answer: D (4 Only)

Source: Boswell MV, Board Review 2004

Answer 214

A

Answer: B (1 & 3)
Explanation:
There are signifi cant clinical differences between
visceral and cutaneous nociception.
There are relatively fewer nociceptors in the viscera than
in the skin, and these receptors may have a different
activation profi le.
Cutting and burning mesentery, uterine cervix, or other
organs does not necessarily produce clinical “pain”, but
traction, distention, or ischemia will produce pain.
Visceral is often diffuse and poorly localized and often
has a significant autonomic component.

Answer 215

A

Answer: D (4 Only)

Source: Lou Etal. Pain Practice: march 2001

Answer 216

A

Answer: D (4 Only)

Source: Rozen. Pain Practice: SEP 2001

Answer 217

A

Answer: E (All)
Explanation:
Pain following peripheral nerve damage has long been
recognized as having a sympathetic component.
It is clear that sympathetic afferents can transmit
information of a nociceptive nature.
One of the characteristics of this pain is that is
accompanied by sympathetic efferent overactivity. This
may be refl ected in alterations in the control of blood fl ow
to the skin, muscles, and bone in the affected area and
alterations in piloerection, sweating, and possibly
cutaneous nociceptive sensitivity.
Source: Kahn and Desio

Answer 218

A

Answer: D (4 Only)

Source: Rozen. Pain Practice: SEP 2001

Answer 219

A

Answer: A (1, 2, & 3 )

Source: Lou Etal. Pain Practice: march 2001

Answer 220

A

Answer: B (1 & 3)

Answer 221

A

Answer: E (All)
Explanation:
G-protein receptors are a large (> 100) family of
membrane spanning receptors that undergo a conformational change with drug-receptor binding which
in turn causes activation of “G-Proteins” [di- or
triphospho-guanosine-binding proteins (G-GDP, GGTP)].
All cells contain G-protein receptors, but the brain
has the highest concentration and the gut is especially rich.
G-proteins produce pharmacological effects through their
control or regulation of membrane-bound, second
messenger systems such as ion channels, cyclic AMP, or
phosopholipases (the phosphoinositol turnover system)
and protein kinases.
Source: Boswell MV, Board Review 2004

Answer 222

A

Answer: C (2 & 4)
Explanation:
Glutamic acid is an excitatory neurotransmitter secreted
by many of the sensory pathways of the CNS.
Glycine is secreted mainly at synapses in the spinal cord,
where it functions predominantly as an inhibitory
neurotransmitter.
Substance P is an excitatory neurotransmitter presumed
to be released by terminals of pain fi bers in the substantia
gelatinosa of the spinal cord.
GABA is an inhibitory neurotransmitter secreted by
neurons in diverse areas of the nervous system including
the spinal cord, cerebellum, and basal ganglia.

Answer 223

A

Answer: B (1 & 3)

Answer 224

A

Answer: B (1 & 3)

Answer 225

A

Answer: A (1, 2, & 3 )
Explanation:
Criteria for proving that a substance is a neurotransmitter
for a primary afferent nociceptor are:
(1) presence of the substance in the dorsal horn synapse of
the primary afferent,
(2) release of the substance on noxious stimulation,
(3) the same effect by release of the substance and
stimulation of the primary afferent, and
- Blockade of the effect of both the substance and the
primary afferent by administration of an antagonist.
Source: Kahn and Desio

Answer 226

A

Answer: E (All)
Explanation:
1.The facial nerve carries parasympathetic secretory fi bers
to the salivary and lacrimal glands and to the mucous
membranes of the oral and nasal cavities.
The facial nerve contributes to the afferent limb of the
orbicularis oculi refl ex in conjunction with the trigeminal
nerve.
The facial nerve innervates the muscles of facial
expression.
The facial nerve conveys various types of sensation, including exteroceptive sensation from the region of the
ear drum, taste sensation from the anterior two-thirds of
the tongue, and general visceral sensation from the salivary
glands and mucosa of the nose and pharynx.

Answer 227

A

Answer: E (All)
Explanation:
Unconscious sensation is mediated by the
spinocerebellar tract.
The Fibers associated with proprioception and crude
touch enter the dorsal horn and ascend ipsilaterally in the
dorsal columns (fasciculus gracilis and fasciculus
cuneatus).
The spinothalamic tract subserves the sensations of pain
and temperature.
The Fibers associated with proprioception and crude
touch enter the dorsal horn and ascend ipsilaterally in the
dorsal columns (fasciculus gracilis and fasciculus
cuneatus).

Answer 228

A

Answer: B (1 & 3)
Explanation:
Administration of substance P provokes plasma
extravasation; other peptides do not produce
extravasation.despite its role in the initiating and
augmentation of neurogenic infl ammation.
Substance P does not produce pain on local injection.
Substance P causes neurogenic infl ammation.
Substance P does not activate nociceptors.

Answer 229

A

Answer: A (1, 2, & 3 )
Explanation:
Centrifugal control of nociceptive transmission through
the dorsal horn arises from a variety of structures that
project descending inhibitory pathways.
1, 2, 3. The pathways descending from these areas
primarily involve noradrenergic, serotonergic, and
enkephalinergic mechanisms. However, other mechanisms
might also be involved.
Source: Kahn and Desio

Answer 230

A

Answer: A (1, 2, & 3 )
Explanation:
Diminution of the reflexes usually results from an
interference with the conduction of an impulse through
the reflex arc. Absence indicates a break in the reflex arc.
1, 2. The muscle-stretch reflexes may be either diminished
or absent in deep coma, narcosis, deep sedation, and often
in deep sleep.
Hypothyroidism and severe toxemias result in
diminished or lost reflexes.
Muscle-stretch refl exes are typically increased with
pyramidal system lesions, early stages of coma and
anesthesia, tetany, tetanus, and strychnine poisoning.
Source: Kahn and Desio

Answer 231

A

Answer: D
Explanation:
The term spondylolisthesis occurs when the cephalad
vertebral body slip forward with respect to the inferior
vertebral body. This slip can be graded in terms of
percentage or grade (grade 1 76%). Etiologies include a
bilateral pars defect (spondylolysis), degenerative changes
in the facet joint, disc incompetence, cancer, infection,
post-surgical (wide decompression). Nonetheless,
spondylolisthesis refers to the slip and not the etiology.
Not all cases of bilateral pars defects will go on to develop
spondylolisthesis.
Unilateral pars defects are unlikely to lead to slip.
Retrolisthesis, which can occur with disc incompetence
and segmental instability, refers to posterior slippage of
the superior vertebral body with respect to the inferior
vertebral body. Segmental instability represents a
condition where a functional spinal unit (2 VBs and the
intervertebral disc) are hyper-mobile. At L5-S1, this
represents >11-15 degrees of motion compared to other
segment or >5 mm of anterior translation.
Source: Shah RV, Board Review 2006

Answer 232

A

Answer: E (All)
Explanation:
After injury just outside their receptive fi elds, C-PMNs
become sensitized and develop spontaneous
depolarization.
1, 2, 3. This activity of C-PMNs in areas of undamaged
tissue causes spreading vasodilation, edema, and further
sensitization of other C-PMNs within adjacent receptive
fi leds. This sequence of events has been termed neurogenic
infl ammation because of its similarity to the infl ammatory
process.
Secondary hyperalgesia depends on activity in
unmyelinated primary afferents with sensitization of CPMNs.

Answer 233

A

Answer: A ( 1, 2, & 3)

Source: Boswell MV, Board Review 2004

Answer 234

A

Answer: A (1, 2, & 3 )

Answer 235

A

Answer: B (1 & 3)
Explanation:
The receptive fi eld for a C-PMN may be quite large (up
to 17mm2).
C-PMNs become sensitized after repeated noxious
stimulation and may develop an ongoing discharge.
Secondary hyperlgesia depends on activity in
unmyelinated primary afferents with sensitization of CPMNs.
Respond to mechanical, thermal and chemical stimuli.
(DR M CHECK)
Source: Kahn and Desio

Answer 236

A

Answer: C (2 & 4)
Explanation:
Application of a brief noxious stimulus will initially be
experienced as a brief, sharp pain (fi rst pain).
A more prolonged, dull sensation (second pain) follows
after a short lull. Application of pressure will block fi rst
pain.
Application of local anesthetics will block second pain.
First pain is preferentially blocked by pressure.
First pain is mediated by the A-delta mechanothermal
nociceptor.
First pain can occur in response to a thermal stimulus.
Source: Kahn and Desio

Answer 237

A

Answer: B (1 & 3)
Explanation:
They are myelinated.
They respond to mechanical stimulation.
Myelinated fi bers activated by noxious stimuli generally
conduct in the A-delta range, about 20 m/s.
A-delta fi bers are called high-threshold
mechanoreceptors.
Answer: A (1, 2, & 3 )

Answer 238

A

Answer: A (1, 2, & 3 )
Explanation:
- The prostanoids are the arachidonic acid metabolites of the cyclooxygenase pathway that comprise the
thromboxanes, prostacyclins, and prostaglandins.
- The eicosanoids are the arachidonic acid metabolites of
the lipoxygenase pathway including 5-
hydroxyeicosatetraenoic acid (5-HETE) and the
leukotrienes.

Answer 239

A

Answer: C (2 & 4)
Explanation:
After repeated thermal stimulation, HTMs will become
more sensitive (achieve a lower threshold to thermal
stimulation) and will increase their frequency of discharge.
This process is known as sensitization.
High-threshold mechanoreceptors (HTMs) do not fi re
in response to thermal stimulation unless stimuli are
applied repeatedly.
The threshold for mechanical stimulation is unchanged
by this process.
Sensitization of high-threshold mechanoreceptors,
results in increased frequency of discharge.

Answer 240

A

Answer: B (1 & 3)
Explanation:
The characteristic sequence of events following a skin
injury is known as the triple response:
Local edema (wheal).
Intense vasodilation.
Secondary vasodilation spreading to adjacent regions
(fl are).
The subject will also note a decreased threshold to
noxious stimuli and increased pain in response to noxious
stimulation (primary hyperalgesia) in the injured area.

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