peripheral pain

Question 1

2 types of receptors involved in pain transduction

Answer 1

TRP (transient receptor potential) receptors

ENaCS (epithelial sodium channels)

Question 2

many TRP receptors have ____ characteristics: responding to ____ stimuli

Answer 2

polymodal; thermal, chemical, and mechanical

Question 3

epithelial sodium channels may play a role in _____ (this is speculative)

Answer 3

mechanical nociception

Question 4

vanilloid receptor (TRPV1 or V1) responds to:

Answer 4

1. capsaicin
2. heat (42degreeC)
3. protons

Question 5

stimulation of vanilloid receptor results in _____

Answer 5

influx of cations (Na+ and Ca++)

Question 6

response of c-fibers (A-delta) to chemical stimuli

Answer 6

chemesthesis

Question 7

chemesthesis evolved as part of a chemical _____; can initiate expulsive reflexes such as ___ or ____

Answer 7

defensive mechanism; coughing; sneezing

Question 8

chemesthesis also produces both ____ and ____ sensations

Answer 8

painful and non-painful (such as burning, tingling (carbonation), astringency, pungency)

Question 9

branches of trigeminal nerve with prominent chemesthesis

Answer 9

nasal: ethmoid n. (branch of ophthalmic)
oral: posterior palatine and nasopalatine nn. (branches of maxillary) & lingual n. and buccal n. (branches of mandibular)

Question 10

both olfaction and chemesthesia can be activated ____ and _____

Answer 10

orthonasally; retronasally

Question 11

olfaction is via _____

Answer 11

olfactory receptors

Question 12

nasal chemesthesis produced by:

Answer 12

1. TRP receptors on ethmoid fibers

2. “taste receptors” on specialized olfactory epithelium cells (single chemosensory cells)

Question 13

chemesthesis mediated primarily by ____

Answer 13

TRP receptors (and some taste receptors in nasal epithelium)

Question 14

dentinal tubules contain ____ fibers that extend _____ mm into tubules

Answer 14

A-delta; 0.1-0.2

Question 15

A-delta fibers contain ____ and have ____ and ____ sensitivity

Answer 15

calcitonin gene related peptide (CGRP); mechanical; thermal

Question 16

exposed dentin from abrasion and lesions causes _____

Answer 16

sharp pain

Question 17

the pulp chamber contains ____ fibers that contain ____

Answer 17

C fibers; substance P

Question 18

C fibers have ____ sensitivity and chemosensitivity to _____

Answer 18

thermal; inflammatory mediators

Question 19

inflammation to the pulp chamber causes a _____

Answer 19

dull throbbing pain

Question 20

mechanical forces that activate dentinal A-delta fibers

Answer 20

scraping, air blast, osmotic stimulus, dental bur

Question 21

dentinal A fibers can respond to ____, not necessarily applied in the “pain” range; however, the sensation from this type of stimulation is ____

Answer 21

temperature; sharp pain

Question 22

the ethmoid n. is sensitive to smelling ____

Answer 22

salts (ammonia)

Question 23

how capsaicin causes desensitization of primary afferent nociceptor mechanisms

Answer 23

• inactivation of voltage-gated ion channels

- depletion of neuropeptides

Question 24

____ reside in the pulp chamber and contain ____, a neuropeptide

Answer 24

c-fibers; substance P

Question 25

c-fibers respond to ____ and ____ stimuli

Answer 25

temperature; chemical stimuli (inflammatory mediators like bradykinin)

Question 26

____ fibers extend into dentinal tubules and contain ____

Answer 26

a-delta; calcitonin gene related peptide (CGRP)

Question 27

A-delta fibers have ___ and ____ sensitivity

Answer 27

mechanical; thermal

Question 28

schwann cells proliferate and produce ____ for substrate for regenerating axons

Answer 28

laminin

Question 29

schwann cells secrete ____ which is transported to ganglion cell body

Answer 29

nerve growth factor (NGF)

Question 30

NGF regulates ____ and promotes _____

Answer 30

gene expression; sprouting