Deck 7: Somatosensation: Clinical Application

Question 1

The role of enkephalins in the spinal cord is:

A)To decrease release of substance P from the primary afferent.
B)To hyperpolarize spinal interneurons in the pain pathway.
C)To stimulate non-nociceptive interneurons of the dorsal horn.
D)A and B
E)A,B,and C

Answer 1

D
Explanation: Enkephalins bind with receptor sites on both the primary afferents and interneurons of the pain system.Enkephalin binding depresses the release of substance P and hyperpolarizes the interneurons,thus inhibiting the transmission of nociceptive signals.

Question 2

If only one sensory root is severed,does a complete loss of sensation result in that area?

A)Yes.Sensation does not depend on multiple dermatomes.
B)No.Overlapping dermatomes ensure not all sensation is lost.
C)No.Multiple sensory roots must be severed for complete sensory loss to occur.
D)Yes.Overlapping dermatomes will not prevent complete sensation loss.

Answer 2

B
Explanation: The results of somatosensory testing procedures can be used to map a person's pattern of sensory loss.The resulting map can be compared with standardized maps of peripheral nerve distribution and of dermatome distributions to determine whether the person's pattern of sensory loss is consistent with a peripheral nerve or a spinal region pattern.Because every individual is unique and adjacent dermatomes overlap one another,the maps presented represent common but not definitive nerve distributions.The overlap of adjacent dermatomes also ensures that if only one sensory root is severed,then a complete loss of sensation does not occur in any area.

Question 3

Which of the following is(are)part of the pain matrix?

A)Amygdala
B)Thalamus
C)Hypothalamus
D)All of the above

Answer 3

D
Explanation: The pain matrix includes parts of the brainstem,amygdala,hypothalamus,thalamus,and cerebral cortex.

Question 4

Which of the following is not measured during a complete sensory evaluation?

A)Proprioceptive thresholds
B)Conscious touch sensitivity
C)Thresholds for stimulation
D)All of the above

Question 5

Sensory extinction is the:

A)Inability to recognize any sensations consciously.
B)Loss of conscious proprioception.
C)Same as astereognosis.
D)Awareness of stimuli on only one side of the body when both sides of the body are simultaneously stimulated.
E)Inability to localize a pinprick on one side of the body.

Question 6

When the raphespinal tract is active,which neurotransmitter is released at the axon terminal in the dorsal horn of the spinal cord?

A)Norepinephrine
B)Gamma-aminobutyric acid (GABA)
C)Dopamine
D)Substance P
E)Serotonin

Question 7

What does the counterirritant theory hypothesizes a mechanism affecting:

A)Pain transmission
B)Pain treatment
C)Pain amplification
D)None of the above

Question 8

The locus coeruleus is located in which one of the following?

A)Spinal cord dorsal horn
B)Medulla
C)Pons
D)Midbrain
E)Cerebral cortex

Question 9

Which of the following are not endorphins?

A)Dynorphins
B)ẞ-Endorphins
C)Enkephalins
D)All of the above are types of endorphins.

Question 10

Which of the following are NOT characteristics of acute pain?

A)Threat of or actual tissue damage
B)Dysfunction of endogenous pain control systems
C)Clear description of the location of the pain
D)Excessive autonomic activity

Question 11

If sitting with the legs crossed,sensory loss will eventually occur.(Part of the limb will "fall asleep.")In what order will this loss occur? (Hint: compression of a nerve affects function in order according to axon diameter and myelination;largest diameter myelinated axons are affected first)

A)1.Slow pain;2.heat;3.fast pain;4.cold;5.conscious proprioception and discriminative touch
B)1.Conscious proprioception and discriminative touch;2.heat;3.fast pain;4.cold;5.slow pain
C)1.Conscious proprioception and discriminative touch;2.cold;3.fast pain;4.heat;5.slow pain
D)1.Slow pain;2.cold;3.fast pain;4.heat;5.conscious proprioception and discriminative touch

Question 12

The periaqueductal gray is located in which one of the following?

A)Spinal cord dorsal horn
B)Medulla
C)Pons
D)Midbrain
E)Cerebral cortex

Question 13

What numerical value(s)is (are)involved in determining whether the results of a nerve conduction study are normal?

A)Conduction velocity
B)Distal latency
C)Amplitude of the evoked potential
D)All of the above

Question 14

Which of the following guidelines will improve the reliability of sensory testing?

A)Explain the purpose of the testing.
B)Administer the test in a loud environment.
C)Apply stimuli near the center of the dermatomes being tested.
D)A and C

Question 15

Lesions in what location(s)will result in decreased or lost sensation from the contralateral body or face?

A)Ventral posterolateral (VPL)nucleus of the thalamus
B)Ventral posteromedial (VPM)nucleus of the thalamus
C)A and B
D)None of the above

Question 16

Which of the following is a site in the nervous system where the transmission of nociceptive information can be altered?

A)Hormonal system
B)Dorsal horn
C)Cortical level
D)All of the above

Question 17

Loss of pain and temperature information from the left lower limb below the L4 dermatome,complete loss of discriminative touch and conscious proprioception information from the right lower limb below the L2 dermatome,and loss of voluntary control of the right lower limb below the L2 dermatome indicates which one of the following?

A)Brown-Séquard syndrome produced by a hemisection of the cord at L4 on the right side
B)Brown-Séquard syndrome produced by a hemisection of the cord at L4 on the left side
C)Brown-Séquard syndrome produced by a complete transection of the cord
D)Brown-Séquard syndrome produced by a hemisection of the cord at L2 on the right side
E)Brown-Séquard syndrome produced by a hemisection of the cord at L2 on the left side

Question 18

Which of the following is(are)part of the fast-descending neuronal system for pain inhibition?

A)Rostral ventromedial medulla
B)Periaqueductal gray
C)Locus coeruleus
D)A,B,and C
E)None of the above