Pain and Temperature

Question 1

Nociceptors

Answer 1

receptors that respond to noxious stimuli resulting from skin or soft tissue injury

Question 2

Nociceptive pain

Answer 2

pain resulting from nociceptor activation due to tissue injury and resultant inflammation

Question 3

Neuropathic pain

Answer 3

pain resulting from direct insult to the nerve

Question 4

How is fast sharp pricking pain transmitted to the spinal cord?

Answer 4

by myelinated A delta fibers carrying thermal and mechanical noxious stimuli

Question 5

How is slow dull pain transmitted to the spinal cord?

Answer 5

by unmyelinated C fibers that carry high intensity thermal, chemical, and mechanical noxious stimuli.

Question 6

How does pain from the viscera enter the spinal cord?

Answer 6

The same way somatic pain does

Question 7

What is primary hyperalgesia?

Answer 7

Sensitization of surrounding nociceptors after injury or inflammation

Question 8

What causes primary hyperalgesia?

Answer 8

Release of chemicals from different injured cells decrease the nociceptor’s activation threshold

Question 9

What is central hyperalgesia?

Answer 9

Sensitization of dorsal horn cells after injury

Question 10

What may central hyperalgesia result in?

Answer 10

a long-term decrease of the pain threshold of the patient

Question 11

Where do central axons of A delta and C fibers synpase?

Answer 11

Generally, they ascend two segments in the dorsolateral fasciculus before synapsing in the dorsal horn

Question 12

What do primary afferent central axons of A delta and C fibers synapse with?

Answer 12

nucleus proprius, pericornual cells and substantia gelatinosa

Question 13

The axons of the nucleus proprius cross the midline and form…

Answer 13

the lateral spinothalamic tract

Question 14

The lateral spinothalamic tract ascends to…

Answer 14

the thalamus in the anterolateral system

Question 15

The lateral spinothalamic tract sends collaterals to…

Answer 15

to the reticular formation, the periaqueductal gray (involved in the emotional reactions to pain), nucleus gracilis and cuneatus and the hypothalamus (for autonomic control of pain)

Question 16

After the spinothalamic fibers synapse in the thalamus those fibers ascend to…

Answer 16

the sensory cortex

Question 17

The gate control theory of pain

Answer 17

based on the observation that proprioceptive and mechanical (non nociceptive) stimulation diminishes the perception of pain

Question 18

A delta mechanoreceptors send collaterals to ___ which in turn inhibits ___

Answer 18

substantia gelatinosa
nucleus proprius

Question 19

A delta and C nociceptors send excitatory signals to ___ while inhibiting ___

Answer 19

nucleus proprius
substantia gelatinosa

Question 20

What do mechanoreceptors do to pain?

Answer 20

turn off pain

Question 21

What do nocireceptors do to pain?

Answer 21

turn on pain

Question 22

Stimulation of the periaqueductal gray results in…

Answer 22

profound and specific analgesia (subject can feel touch and vibration but not pain) and blocks withdraw reflexes in response to painful stimuli

Question 23

The periaqueductal gray can excite…

Answer 23

the serotoninergic raphe nuclei and the noradrenergic locus coeruleus

Question 24

Serotoninergic raphe nuclei and the noradrenergic locus coeruleus send fibers that travel in the fasciculus of Lissauer to…

Answer 24

inhibit the output of the pericornual cells and the nucleus proprius

Question 25

Descending inhibitory pathways ultimately interfere with…

Answer 25

glutamate secretion of primary pain afferents

Question 26

Opioid administration in the periaqueductal gray results in

Answer 26

anesthesia

Question 27

What was discovered through the use of morphine and codeine as effective pain relievers?

Answer 27

opiate receptors and endogenous opioids

Question 28

What accounts for different symptoms of opiate use not related to pain control?

Answer 28

µ, b and k opiate receptors have been identified also occurring in various areas of the nervous system