EX1; Peripheral Pain

Question 1

This type of pain is short term with an identifiable source

Answer 1

acute pain

Question 2

This type of pain is long term frequently with a non-identifiable source

Answer 2

chronic pain

Question 3

This type of fiber makes up roughly 13% of cutaneous nociceptors, while this fiber makes up roughly 87%

Answer 3

13%; A-delta

87%; C fibers

Question 4

Which fiber is tiny (0.2-1.5µm) and is unmyelinated and which one is small (1-5µm) and is lightly myelinated

Answer 4

tiny/unmyelinated = C
small/myelinated = Adelta

Question 5

Which fiber has a faster conduction velocity (12-36m/s) compared to 0.5-1.2m/s

Answer 5

Adelta is faster than C

Question 6

Which fiber has neuropeptides (but limited)

Answer 6

Adelta

Question 7

Which fiber has its Na channels both TTX-sensitive (typical) and TTX-r (sensory-nerve specific)

Answer 7

C fibers

A delta is just mainly TTX-sensitive (typical)

Question 8

What are the response properties of A delta fibers

Answer 8

noxious mechanical stimuli
some noxious heat
chemical stimuli; inflammatory mediators but not capsaicin

Question 9

What are the response properties of C fibers

Answer 9

varied stimuli buy many POLYMODAL (but all noxious)

Question 10

What is the TRPV-1/2 expression for Adelta and C fibers

Answer 10

A delta; TRPV-1 expression is rare, TRPV-2 more likely

C fibers; many express TRPV-1

Question 11

This fiber is the first pain, fast, sharp, and well localized

Answer 11

A delta

Question 12

This fiber is 2nd pain, slow, dull or burning, poorly localized pain

Answer 12

C fibers

Question 13

These channels may play a role in mechanical nociception; very speculative

Answer 13

ENaCS (epithelial sodium channels)

Question 14

This is a large family of receptors transducing chemical and thermal nocicpetion (possibly mechanoreception)

Answer 14

transient receptor potential (TRP)

Question 15

TRP receptors are also involved with the is type of transduction

Answer 15

non-noxious thermal transduction

Question 16

TRP receptors found here respond to chemicals to mediate chemesthesis

Answer 16

trigeminal sensory fibers

Question 17

TRP receptors are also found here; with a possible role in tooth pain

Answer 17

odontoblasts

Question 18

C-fibers innervating the oral and nasal mucosa have a small receptive field and what kind of chemorecpetive properties

Answer 18

polymodal

Question 19

Specialized ending and chemesthesis allow for an important distinction between what

Answer 19

taste and olfaction

Question 20

The response of trigeminal C-fibers that signals pain and sensations associated with what

Answer 20

spicy food; capsaicin

burning and tingling

Question 21

This term means no olfactory sensation

Answer 21

anosmic

Question 22

A large proportion of polymodal c-fibers and a few a-deltas are sensitive to what

Answer 22

capsaicin

Question 23

Vanilloid receptor (TRPV1 or V1) responds to what three things

Answer 23

capsaicin
heat (42°C)
protons

Question 24

stimulations of vanillin receptors results in what

Answer 24

the influx of cations (Na and Ca)

Question 25

What are the branches of the trigeminal nerve with prominent chemesthesis

Answer 25

nasal; ethmoid (smelling salts) | oral; posterior palatine, nasopalatine, lingual nerve

Question 26

Is chemesthesis high or low threshold chemosensitivity

Answer 26

high

Question 27

What is the predominate type of sensation of chemesthesis

Answer 27

aversive; burning, tingling

Question 28

Chemesthesis also plays a role in "removal" reflexes such as what

Answer 28

salivation coughing tearing sneezing

Question 29

Chemesthesis can also be activated by two other things

Answer 29

dental compounds | drugs (capsaicin compounds) for pain treatment

Question 30

These fibers are found 0.1-0.2mm into dentinal tubules and are associated with sharp pain

Answer 30

a-delta fibers

Question 31

The a-delta fibers of dentinal tubules contain what, associated with mechanical and thermal sensitivity, also chemical stimuli like NaCl.

Answer 31

calcitonin gene-related peptide (CGRP)

Question 32

These fibers are found in the tooth pulp and contain substance P; initiating a dull, throbbing pain

Answer 32

c fibers

Question 33

What kind of sensitivity do c-fibers respond to

Answer 33

thermal sensitivity | chemosensitivity to inflammatory mediators (bradykinin)

Question 34

This theory holds that despite the lack of innervation of the DEJ, this area is sensitive to mechanical, thermal, and chemical stimuli causing fluid to flow in the tubules

Answer 34

hydrodynamic theory

Question 35

Fluid flow of the hydrodynamic theory causes what to occur, stimulating a response

Answer 35

the fluid flow causes distortion in proximal parts of dentinal tubules where the sensory endings are located, thus stimulating the receptor

Question 36

What evidence supports the hydrodynamic theory of pain

Answer 36

noxious temperature was applies to dentin and subjects reports of pain were directly correlated between the integrated nerve activity (INA) and increased pain response (PAS), since the pain was described as "sharp" this indicates that they are a-delta fibers of which are found in the tubules

Question 37

This is extremely important in the transduction process involving the hydrodynamic theory, when this was removed, subjects experienced pain

Answer 37

smear layer

Question 38

What are the three major characteristics of hyperalgesia

Answer 38

1. greater responsiveness to stimuli (both nociceptive and low-threshold) 2. pain is spontaneous in occurrence (lack of obvious stimulus) 3. pain is prolonged

Question 39

Interactions between what things can induce hyperalgesia

Answer 39

interactions between different neural systems (afferent/efferent( interactions between nervous and non-nervous cells

Question 40

This stimulates nociceptors to secrete substance P which in turn releases histamine, in turn, re-stimulates nociceptor

Answer 40

thermal or mechanical injury

Question 41

Histamine also promotes these two things which can further act as a mechanical stimulus on nociceptors

Answer 41

``` vasodilation plasma extravasation (swelling) ```

Question 42

This results in the release of bradykinin which stimulates nociceptors and further result in stimulation of histamine release from mast cells

Answer 42

bleeding

Question 43

This results in leukocyte products such as prostaglandins sensitize cells rather than directly stimulate them to produce action potentials

Answer 43

infection

Question 44

Many of cells involved in an inflammatory reaction release factors that are either these three things

Answer 44

algesics stimulate other cells to release factors that are algesics (subP stimulates mast cells to release histamine) do not directly stimulate nociceptor neurons but are involved in the process of sensitization

Question 45

This is something that directly stimulates nociceptor cells

Answer 45

algesics; like bradykinin

Question 46

The vanilloid receptor undergoes this, by becoming more sensitive to heat and capsaicin after protons are released in an inflamed area; more sensitive (22 degrees instead of 44) to other stimuli now

Answer 46

hyperalgesia

Question 47

C-fibers contain this, which unlink A fibers, require greater depolarization thus leading to a higher threshold

Answer 47

TTX-insensitive sodium channels

Question 48

C-fibers have small conductance K channels that function to do what

Answer 48

prolong the period of hyperpolarizaion following an action potential; thus producing fewer action potentials per unit of depolarization compared to A fibers

Question 49

The K channels in C fibers can be blocked by what, thus returning the membrane potential of transmitting painful signals; "sensitized"

Answer 49

prostaglandins

Question 50

This is a burning pain associated with nerve damage

Answer 50

causalgia

Question 51

This is light touch leading to pain associated with nerve damage

Answer 51

allodynia

Question 52

This is temperature induced pain associated with nerve damage

Answer 52

sympathetic nerve dystrophy

Question 53

This is sensation in denerved tissue associated with nerve damage

Answer 53

phantom sensations

Question 54

This type of change is toward the cell body; such as ganglion cell death if the axon is cut near the cell body

Answer 54

retrogrades chages

Question 55

If cell death does not occur, the cell body can undergo this, which the cell swells and the nucleus moves to an eccentric position and the RER moves to the side

Answer 55

chromatolysis

Question 56

Chromatolysis is a historical marker for what

Answer 56

damages or injured cell and is associated with increases protein synthesis in response to repair or injury

Question 57

True or False Increased protein synthesis of a damaged nerve can lead to changes in cell properties like if more channel proteins are made, then that cell may become more sensitive to new things also due to lack of myelin

Answer 57

True

Question 58

Damage to the axon can result in this, in which the axon process heading towards the CNS degenerates

Answer 58

transganglionic degeneration

Question 59

This can occur in which the neuron contacted centrally by the axon dies

Answer 59

transneuronal degeneration

Question 60

What are two anterograde changes associated with nerve injury

Answer 60

terminal degeneration of axon terminal | wallarian anterograde degeneration of axon

Question 61

These in the vicinity of the lesion proliferate and produce ECM that provides substrate for regenerating axon

Answer 61

Schwann cells

Question 62

This phenomenon is most likely to occur when an axon fails to regenerate; a surviving axon may grow new terminals into the area previously occupied by the other sensory cell

Answer 62

sprouting

Question 63

Can sprouting have functional significance?

Answer 63

yes, has been indicated in a human subject

Question 64

These can form which reflect the regenerative capacity of injured nerves; it is anatomically characterized as a tangled complex, disorganized web of neural tissue, leading in some instances to painful conditions when palpated or arising spontaneously

Answer 64

neuromas

Question 65

An up regulation of Na channels makes for increased excitability and this, which is when a neuron responds, not from its receptor ending, but from stimulation of the cell body or axon

Answer 65

ectopic discharge

Question 66

What two phenomena can cause pain in an neuroma

Answer 66

sprouting; fibers with central connections that signal pain (nociceptor stimulation) ephaptic; (non-synaptic) connections between neurons in neuroma such that low threshold mechanoreceptors now activate pain fibers

Question 67

This is when a neuron responds to action potentials from nearby neuron; could account for allodynia and referred pain

Answer 67

ephaptic