OTHER SOMATIC SENSATIONS

Question 1

afferent impulse frequency ________ is
encoded by the brain in terms of magnitude or intensity
of sensation.

In addition, as the intensity of stimulation
increases, more sensory units are activated _________

Answer 1

temporal summation

spatial summation
.

Question 2

________________ is defined as a dorsal root ganglion cell, its central and distal
processes, and all the sensory endings in the territory
supplied by those distal processes (the receptive field ofthe sensory cell).

Answer 2

peripheral sensory

unit

Question 3

Fibers that mediate _________ are located in

cutaneous sensory or mixed sensorimotor nerves

Answer 3

superficial sensation

Question 4

The myelinated fibers are of two types:

small, lightly myelinated, A-b fibers for ________

faster-conducting A-d fibers for

Answer 4

pain and cold,

touch and pressure.

Question 5

Two aspects of itch are recognized:

a brief primary ___________itch at the site of stimulus or injury, and a subsequent more ___________ sensation that is greatly intensified by
gentle touch.

Answer 5

localized

diffuse

Question 6

Itch sensation is transmitted by specific_______

fibers

Answer 6

C

Question 7

Large and heavily myelinated
fibers enter the cord just __________ to the dorsal hom and
divide into ascending and descending branches

Answer 7

medial

Question 8

Of the long ascending posterior column fibers, which
are activated by mechanical stimuli of skin and subcutaneous
tissues and by movement of joints, only about ________(from the lumbar region) reach the gracile nuclei at
the upper cervical cord

Answer 8

25

percent

Question 9

An estimated 20 percent of
ascending fibers originate from cells in Rexed ________ and convey impulses from low-threshold mechanoreceptors that are sensitive to
hair movement, skin pressure, or noxious stimuli

Answer 9

layers IV and

V of the posterior horns

Question 10

Observations based on surgical interruption of
the anterolateral funiculus indicate that fibers mediating
touch and deep pressure occupy the __________

Answer 10

ventromedial part

anterior spinothalamic tract

Question 11

After entering the pons, the pain and temperature
fibers turn caudally and run through the ipsilateral
medulla as the__________, terminating
in the long, vertically oriented _______________, that lies beside it and extends
to the second or third cervical segment of the cord, where it becomes continuous with the posterior horn of the spinal gray matter.

Answer 11

descending spinal trigeminal tract

nucleus caudalis, or
spinal trigeminal nucleus

Question 12

The ventral posterior thalamic nucleus receives fibers
from the ___________________
(fibers from the principal sensory and spinal trigeminal
nuclei) tracts, and projects mainly to two somatosensory
cortical areas.

Answer 12

medial lemniscal, spinothalamic, and trigeminal

Question 13

The first area (Sl ) corresponds to the __________________. Sl afferents
are derived primarily from the ventral posterolateral
nucleus (VPL, the terminus of medial lemniscal and
spinothalamic fibers) and the ventral posteromedial
nucleus (VPM, the terminus of trigeminal fibers) and
are distributed somatotopically,

The second somatosensory area (S2) lies on the __________

Answer 13

postcentral cortex or Brodmann areas 3, 1, and 2

upper bank of the sylvian fissure, adjacent to the insula.

Question 14

Experimental data support the view that partially
damaged touch, pressure, thermal, and pain fibers
become _______________
along their course, either spontaneously or in response to a natural volley of stimulus-evoked impulses

Answer 14

hyperexcitable and generate ectopic impulses

Question 15

Another positive sensory symptom
is __________, referring to a phenomenon in which one
type of stimulus evokes another type of sensation-e.g.,
touch may induce pain.

Answer 15

allodynia

Question 16

It is known that stimulation of _________ gives rise to a
sensation of tingling and buzzing;

of ____________, to pseudocramp (the sensation of cramping without actual muscle contraction);

of __________ to heat (including burning) and coldness; and of

________ to prickling and pain.

Answer 16

touch fibers

muscle proprioceptors

thermal fibers,

A-o fibers,

Question 17

Paresthesia arising from ectopic discharges
in large sensory fibers can be induced by nerve
compression, _________________, certain
medications (niacin foremost among them), and diverse
diseases of nerves

Answer 17

hypocalcemia, hypomagnesemia

Question 18

The hyperventilation of anxiety
may cause paresthesia of the lips and hands (sometimes
unilateral)______________and thereby of ionized
calcium; tetany may also occur, with carpopedal
spasms.

Answer 18

from diminution of C02

Question 19

Severe acral and peripheral paresthesias
with perversion of hot and cold sensations are
characteristic of certain ________and some toxins, such as ______

Answer 19

neurotoxic shellfish poisonings (ciguatera)

mercury

Question 20

The effect of aging is most evident in
relation to___________, but proprioception, the perception
of touch, and fast pain are also diminished with
age.

Answer 20

vibratory sense

Question 21

testing of Sn if no Sn abn

Answer 21

it is sufficient to test vibration and position
sense in the fingers and toes and the perception of pinprick
over the extremities, and to determine whether the findings
are the same in symmetrical parts of the body

Question 22

By this method, a stimulus of constant strength can
be applied and the threshold for tactile sensation determined
by measuring the force required to bend a hair of
known length

Answer 22

von Frey hair method

Question 23

One can estimate the perception o f this modality
simply by lightly pinching or pressing deeply on the
tendons, muscles, or bony prominences.

Answer 23

deep pain

Question 24

A quick but rough way to assess thermal loss (or to corroborate
a previously found zone of hypalgesia) is to
_________

Answer 24

warm one side of a tuning fork by rubbing it briskly
against the palm and apply its alternate sides to the
patient’s skin and asking the patient which side is colder
(or warmer).

Question 25

Normally,
a very slight degree of movement is appreciated in the
digits ________

Answer 25

(as little as 1 degree of an arc).

Question 26

Patient with _________ usually will remain stable when they
look at the ceiling or a distant object and then become
very unsteady when the eyes are closed

Answer 26

factitious

unsteadiness,

Question 27

The
conduction of vibratory sense depends on both ______________ that are carried in the muscle
spindle afferent fibers and ascend mainly in the dorsal
columns of the cord.

Answer 27

cutaneous

and deep afferent fibers

Question 28

Vibration sense is tested by placing a tuning fork
with a low rate and long duration of vibration ___________over the bony prominences, making sure that
the patient responds to the vibration, not simply to the
pressure of the fork, and that he is not trying to listen to
it.

Answer 28

(generally

128 Hz)

Question 29

The ability to distinguish two points from one i s tested
by using a compass, the points of which should be blunt
and applied simultaneously and painlessly

Answer 29

Two-Po i nt D i sc r i m i n ati o n

Question 30

Localization o f cutaneous tactile o r painful stimuli is
tested by touching various points on the body and asking
the patient to place the tip of his index finger on the
point stimulated or on the corresponding point of the
examiner’s limb

Answer 30

C uta n e o u s Loca l i zat i o n a n d F i g u re W r it i n g
( G ra p h esth e s i a )

Question 31

Normally, traced numbers as small as___________
can be detected on the pulp of the finger if drawn with
a penci

Answer 31

1 cm

Question 32

Appreciation of texture depends mainly on cutaneous
impressions, but ____________
of objects is based on sensory experience from deeper
receptors as well

Answer 32

recognition of the shapes and sizes