Chapter 7: Somatosensation: Clinical Application

Chapter 7: Somatosensation: Clinical Application

Complete Chapter Questions With Answers

Sample Questions Are Posted Below

1. Sensory extinction is the:
2. Inability to recognize any sensations consciously.
3. Loss of conscious proprioception.
4. Same as astereognosis.
5. Awareness of stimuli on only one side of the body when both sides of the body are simultaneously stimulated.
6. Inability to localize a pinprick on one side of the body.

ANS: D

Rationale: In cases of sensory extinction (also called sensory inattention), the loss of sensation is only evident when symmetrical body parts are tested bilaterally.

2. The role of enkephalins in the spinal cord is:
3. To decrease release of substance P from the primary afferent.
4. To hyperpolarize spinal interneurons in the pain pathway.
5. To stimulate non-nociceptive interneurons of the dorsal horn.
6. A and B
7. A, B, and C

ANS: D

Rationale: 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.

3. When the raphespinal tract is active, which neurotransmitter is released at the axon terminal in the dorsal horn of the spinal cord?
4. Norepinephrine
5. Gamma-aminobutyric acid (GABA)
6. Dopamine
7. Substance P
8. Serotonin

ANS: E

Rationale: When the rostral ventromedial medulla is electrically stimulated, the raphespinal tracts (i.e., the axons projecting to the spinal cord) release the neurotransmitter, serotonin, in the dorsal horn, inhibiting the tract neurons via enkephalin interneurons and thus interfering with the transmission of nociceptive messages.

4. Which of the following is(are) part of the fast-descending neuronal system for pain inhibition?
5. Rostral ventromedial medulla
6. Periaqueductal gray
7. Locus coeruleus
8. A, B, and C
9. None of the above

ANS: D

Rationale: The brainstem areas that provide intrinsic antinociception form a neuronal descending system, arising in the following: rostral ventromedial medulla, periaqueductal gray (PAG) in the midbrain, and locus coeruleus in the pons.