SOMATIC SENSATION

Question 1

two types of afferent fibers in the distal axons

of primary sensory neurons

Answer 1

very fine, unmyelinated, slowly conducting C fiber
(0.3 to l.l).l in diameter);

the other is the thinly myelinated,
more rapidly conducting A-8 fiber (2 to s.u in diameter).

Question 2

Three

categories of free endings or receptors are recognized:

Answer 2

mechanoreceptors, thermoreceptors, and polymodal

nociceptors

Question 3

mechanoeffects are transmitted by both ______

and the thermal effects mostly by ______

Answer 3

A-8 and C fibers

C fibers

Question 4

The peripheral afferent pain fibers of both A-8 and

C types have their cell bodies in the_______

Answer 4

dorsal root ganglia

Question 5

The
pain afferents occupy mainly the _________of the root
entry zone

Answer 5

lateral part

Question 6

That the ____________ is predominantly
a pain pathway is shown (in animals) by
the ipsilateral segmental analgesia that results from its
transection but it contains deep sensory or propriospinal
fibers as well

Answer 6

tract of Lissauer

Question 7

_________ fibers terminate principally in
lamina I of Rexed (marginal cell layer of Waldeyer) and
also in the outermost part of lamina II;

Answer 7

Thinly myelinated (A-0)

Question 8

some A-8 pain
fibers penetrate the dorsal gray matter and terminate
in the lateral part of ______

Answer 8

lamina V.

Question 9

Unmyelinated (C) fibers

terminate in _________

Answer 9

lamina II (substantia gelatinosa)

Question 10

Excitatory amino acids __________ and
nucleotides such as adenosine triphosphate (ATP) are the
putative transmitters at terminals of primary A-8 sensory
afferents.

Answer 10

(glutamate, aspartate)

Question 11

Also,________ afferents, when stimulated,
release several neuromodulators that play a role in the
transmission of pain sensation

Answer 11

A-8 pain

Question 12

animals, __________
excites nociceptive dorsal root ganglion and dorsal hom neurons; furthermore, destruction of substance P fibers
produces analgesia. In

Answer 12

substance P

Question 13

Opiate receptors of three types are found on

both presynaptic primary afferent terminals and postsynaptic dendrites of small neurons in_______

Answer 13

lamina II.

Question 14

axons of secondary neurons that

sub-serve pain sensation originate in laminae ________ of the spinal gray matter.

Answer 14

I, II, V, V.ll,

and Vlll

Question 15

It is of clinical consequence that the axons carrying pain

impulses from each dermatome decussate __________ rostral to the level of root entry

Answer 15

one to three

segments

Question 16

a fast-conducting pathway that projects directly to the
thalamus-the anterolateral fasciculus of the cord contains
several more slowly conducting, medially placed
systems of fibers.

Answer 16

spinoreticulothalamic

or paleospinothalamic pathway

Question 17

The conduction of diffuse, poorly localized pain arising
from deep and visceral structures (gut, periosteum,
peritoneum) has been ascribed to _______________

Answer 17

these slow-conducting, indirect pathways

Question 18

it is the direct spinothalamic
pathway, which projects to the _______ and thence to discrete areas of the sensory cortex, that subserves the sensorydiscriminative aspects of pain

Answer 18

ventroposterolateral

(VPL) nucleus of the thalamus

Question 19

The direct spinothalamic fibers separate into two bundles as they approach the thalamus. The lateral division
terminates in the ventrobasal and posterior groups of
nuclei, the most important of which is the _______

Answer 19

VPL nucleus.

Question 20

The medial contingent terminates mainly in the __________of nuclei and in the nucleus submedius

Answer 20

intralaminar

complex

Question 21

__________ project onto the medial intralaminar (primarily parafascicular and centrolateral) thalamic nuclei; i.e., they overlap with the terminations of the medially projecting direct spinothalamic pathway.

Answer 21

Spinoreticulothalamic (paleospinothalamic) fibers

Question 22

The ventrobasal thalamic complex and the ventroposterior group of nuclei project to two main cortical areas:

the ________ (a small number terminate in the precentral cortex) and the ________

Answer 22

primary sensory (postcentral) cortex

upper bank of the
sylvian fissure.

Question 23

The ______ which also project
to the hypothalamus, amygdaloid nuclei, and limbic cortex,
probably mediate the arousal and affective aspects of
pain and autonomic responses.

Answer 23

intralaminar nuclei,

Question 24

In skeletal muscle, pain
is caused by ischemia (the basis of intermittent claudication),
necrosis, hemorrhage, and injection of irritating
solutions as well as by injuries of ______

Answer 24

connective tissue sheaths.

Question 25

Joints are insensitive to pricking, cutting, and cautery; but pain can be produced in the _______ by inflammation and by exposure to hypertonic saline.

Answer 25

synovial membrane

Question 26

Distention of________ as occurs with thrombotic or embolic occlusion, may be sources of pain;

Answer 26

arteries or veins,

Question 27

These pain-producing substances-which include ____________ as well as potassium ions-elicit pain when they are injected intraarterially or applied to the base of a blister

Answer 27

histamine, | prostaglandins, serotonin, and similar polypeptides,

Question 28

It causes erythema by dilating cutaneous vessels and edema by releasing histamine from mast cells; it also acts as a chemoattractant for leukocytes. This reaction, called neurogenic inflammation

Answer 28

Substance P

Question 29

persons. Inflammation lowers the threshold | for perception of pain by a process called_________

Answer 29

sensitization.

Question 30

``` Strong emotion (fear or rage) suppresses pain, presumably by activation of the above-described __________ ```

Answer 30

descending | noradrenergic system

Question 31

In human subjects, stimulation of the ___________r through stereotactically implanted electrodes has also produced a state of analgesia, though not consistently

Answer 31

midbrain periaqueductal gray matte

Question 32

Opiates also act pre- and postsynaptically on the | neurons of laminae I and V of the dorsal hom, suppressing afferent pain impulses from both ______

Answer 32

the A-8 and C fibers.

Question 33

Prolonged pain and fear are the | most powerful activators of this _______

Answer 33

endogenous opioid-mediated | modulating system.

Question 34

most studied endorphins

Answer 34

B-endorphin, a peptide sequence of the pituitary | hormone /3-lipotropin, and two other peptides, enkephalin and dynorphin.

Question 35

A demonstrable reduction in pain perception (i.e., an elevated threshold) associated with an increased reaction to the stimulus once it is perceived, is sometimes referred to as ________

Answer 35

hyperpathia

Question 36

there is an excessive reaction to all stimuli, even those (such as light touch) that normally do not evoke pain, a symptom termed ________

Answer 36

allodynia

Question 37

Skin pain is of two types: Together they constitute the ________

Answer 37

a pricking pain, evoked immediately on penetration of the skin by a needle point, or a stinging or burning pain that follows in a second or two "double response"

Question 38

_________has indefinite boundaries and its location is distant from the visceral structure involved. It tends to be referred not to the skin overlying the viscera of origin but to other areas innervated by the same spinal segment (or segments) .

Answer 38

Deep pain

Question 39

The convergence of deep and cutaneous afferents on the same dorsal hom cells, coupled with the fact that cutaneous afferents are far more numerous than visceral afferents and have direct connections with the thalamus, is probably responsible for the phenomenon

Answer 39

referred pain.

Question 40

The regions of projection of pain that originate in | the bones and adjacent ligamentous structures

Answer 40

"sclerotomes

Question 41

alteration of the physiologic status of the | pools of neurons in adjacent segments of the spinal cord.

Answer 41

aberrant reference

Question 42

One hypothesis proposes that in an injured nerve, the unmyelinated sprouts of A-8 and C fibers become capable of spontaneous ectopic excitation and afterdischarge and are susceptible to ephaptic activation

Answer 42

C h ro n i c Pa i n

Question 43

ephapse (nerve-to-nerve cross-activation) is thought to be the basis of causalgia (persistent burning and aching pain in the territory of a partially injured nerve and beyond) and its associated____________

Answer 43

reflex sympathetic dystrophy;

Question 44

chronic | pains that fall into one of four categories:

Answer 44

( 1 ) pa􀃆in from an obscure medical disease, the nature of which has not yet been disclosed by diagnostic procedures; (2) pain associated with disease 􀃇f the central or p􀃈riph􀃉ral nervous system (i.e., neurogeruc, or neuropathic pam); (3) pain associated with psychiatric disease; and (4) pain of unknown cause.

Question 45

These terms are generally used interchangeably t o designate pain that arises from direct stimulation of nervous tissue itself, central or peripheral, exclusive of pain as a consequence of stimulation of C fibers by lesions of other bodily structures

Answer 45

N e u rogenic, or N e u ropathic Pa i n

Question 46

The sensations that characterize neuropathic pain | vary and are often multiple-__________________ qualities are described

Answer 46

burning, gnawing, aching, | and shooting or lancinating

Question 47

mechanism of peripheral nerve pain

Answer 47

denervation hypersensitivity,

Question 48

Regenerating axonal sprouts, as in a ___________ are | also hypersensitive to mechanical stimuli.

Answer 48

neuroma,

Question 49

------------------------- accumulate at the site of a neuroma and all along the axon after nerve injury, and that this gives rise to ectopic and spontaneous activity of the sensory nerve cell and its axon.

Answer 49

voltage-gated sodium channels

Question 50

Spontaneous activity in ____________s is thought to give rise to burning pain; firing of large myelinated A fibers is believed to produce _____________ induced by tactile stimuli

Answer 50

nociceptive C fiber dysesthetic pain

Question 51

Evidence that the sodium channel can generate neural pain is given by the extraordinary disease ________ mutation of the sodium channel gene, ________, leads to the early onset of paroxysmal autonomic changes and attacks of excruciating deep burning pain in the rectum, eye, or jaw,

Answer 51

"paroxysmal extreme pain disorder" also known as "familial rectal pain syndrome SCN9A

Question 52

It is characterized by persistent, severe pain in the hand or foot, most pronounced in the digits, palm of the hand, or sole. The pain has a burning qualityand frequently radiates beyond the territory of the injured nerve.

Answer 52

causalgia

Question 53

pathophysiology of causalgia

Answer 53

the result of an artificial connection between efferent sympathetic and somatic afferent pain fibers at the point of the nerve injury

Question 54

__________has been | reported after limb and bone injury but in the absence of evident damage to adjacent nerves.

Answer 54

reflex sympathetic dystrophy

Question 55

Alterations in _________, ___________ and changes in gabanergic inhibition in the dorsal horns are all implicated in RSD

Answer 55

N-methyl-o-aspartate (NMDA) receptors, | induction of cyclooxygenase and prostaglandin synthesis,

Question 56

_________ in which a fixed | dystonic posture is engrafted on a site of causalgic pain

Answer 56

``` causalgia- dystonia syndrome (Bhatia et al) ```

Question 57

Complaints of weakness and fatigue, depression, anxiety; insomnia, nervousness, irritability, palpitations, etc., are woven into the clinical syndrome,

Answer 57

Pa i n in Associati on with Psych iatric Diseases

Question 58

Intractable pain may also be the leading symptom of | both ___________

Answer 58

somatization and conversion reactions.

Question 59

Experienced physicians are familiar with the patient who has undergone multiple surgical procedures to address painful complaints _________

Answer 59

so-called Briquet disease) .

Question 60

Lesions of the ________ regions of one cerebral hemisphere sometimes have peculiar effects on the patient's capacity to feel and react to pain. Under the title of ___________

Answer 60

parietooccipital pain hemiagnosia,

Question 61

There are also two varieties of rare individuals who from birth are totally indifferent to pain coupled with anhidrosis_______________or are incapable of feeling pain___________

Answer 61

("congenital insensitivity to pain") ("universal analgesia").

Question 62

mutation in the neural tyrosine kinase receptor, a nerve growth factor receptor;

Answer 62

("congenital insensitivity to pain")

Question 63

suffer from either a congenital lack of pain neurons in | dorsal root ganglia, or to a mutation in the sodium channel

Answer 63

("universal analgesia")

Question 64

The phenomenon of _________ is another rare and unusual condition wherein the patient, although capable of distinguishing the different types of pain stimuli from one another and from touch,

Answer 64

asymbolia for pain

Question 65

The current | interpretation of asymbolia for pain is that it represents a particular type of __________ and ____________

Answer 65

agnosia (analgognosia) or apractagnosia

Question 66

A useful way in which to undertake the management of chronic pain that affects several parts of the body, as in the patient with metastases, is with____________ taken together with aspirin, acetaminophen, or another nonsteroidal antiinflammatory drug (NSAID), or tramadol.

Answer 66

codeine or oxycodone

Question 67

__________ are sometimes useful drugs with which to begin, because of their effectiveness by mouth and the relatively slow development of tolerance

Answer 67

Methadone and levorphanol

Question 68

provide relief for 24 to 72 h and which we have found particularly useful in the treatment of pain from brachial or lumbosacral plexus invasion by tumor and of painful neuropathies such as those caused by diabetes and systemic amyloidosis.

Answer 68

fentanyl

Question 69

________are believed to prevent the activation of nociceptors by inhibiting the synthesis of prostaglandins in skin, joints, viscera, and other structures in the peripheral nervous system.

Answer 69

Aspirin and | other NSAIDs

Question 70

produce analgesia by acting as "false" neurotransmitters at opiate receptor sites in the posterior horns of the spinal cord-sites that are normally activated by endogenous opioid peptides

Answer 70

Morphine and meperidine

Question 71

Opioids not only act directly on the central pain-conducting sensory systems but also exert a powerful action on the ________

Answer 71

affective | component of pain.

Question 72

Tricyclic antidepressants, especially the ___________ (imipramine, amitriptyline, and doxepin), block serotonin reuptake and thus enhance the action of this neurotransmitter at synapses and putatively facilitate the action of the intrinsic opiate analgesic system

Answer 72

methylated | forms

Question 73

The ____________ seem not to be as effective for the treatment of chronic neuropathic pain

Answer 73

specific serotonin reuptake inhibitors (SSRI) antidepressants

Question 74

A common combination for chronic pain is the addition ____________________ and perhaps not surprisingly, this was superior to either drug alone in a crossover trial in patients with postherpetic neuralgia and diabetic neuropathy

Answer 74

of gabapentin to an opioid such as | morphine,

Question 75

Concoctions such as topical Ketamine mixed in soy lecithin to produce a gel with drug concentration of 5 mg/ml, have been reportedly useful in treating_________

Answer 75

post herpetic neuralgia

Question 76

Aspirin mixed with_________in cold cream is said to be very effective in the topical treatment of post herpetic neuralgia,

Answer 76

chloroform

Question 77

Only when a variety of analgesic medications ______________ and only when certain practical measures, such as regional analgesia or anesthesia, have completely failed, should one turn to neurosurgical procedures.

Answer 77

(including opioids

Question 78

Spinothalamic tractotomy, in which the anterior half of the spinal cord on one side is sectioned at an upper thoracic level, effectively relieves pain in the __________

Answer 78

pposite leg | and lower trunk.

Question 79

__________is also feasible but with greater risk of loss of sphincteric control and, at higher levels, of respiratory paralysis.

Answer 79

Bilateral tractotomy

Question 80

Lesions placed in the ventroposterior nucleus are said to diminish pain and thermal sensation over the contralateral side of the body while leaving the patient with ____________

Answer 80

all the misery or affective experience of pain