Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

D1 Spring - Physiology > 2/9: Thermal Sensation and Nociception II > Flashcards

2/9: Thermal Sensation and Nociception II Flashcards

1
Q

Where are wide-dynamic range neurons found?

A

In the dorsal horn of the spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do WDR neurons respond to?

A

All somatosensory modalities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are WDR neurons normal sensitive to?

A

non-noxious stimuli UNLESS the stimulus is highly
noxious

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is allodynia?

A

perception of non-noxious stimuli as pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When do some second order neurons increase their frequency of activiation?

A

Following prolonged discharge—”wind-up.” May continue, even after
the nociceptive stimulus is removed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the gate control theory of pain?

A

Activation of Alpha beta fibers from the same region
inhibits the Spinothalamic pathway and reduces
pain perception

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The activation of alpha-beta fibers activates what?

A

An inhibitory interneuron
that causes post-synaptic inhibition of the
Second-order neuron for the Pain Pathway
- This inhibition leads to a weaker pain signal being
sent to the thalamus and somatosensory cortex
- This is the basis for how massage therapy and
TENS units work as a treatment for chronic pain
conditions and is why rubbing a painful region
makes it feel better

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does pain inhibit pain?

A

Stimulate pain in other regions of the body to inhibit pain (via GABA)
at second order, WDR, neurons in spinal cord (Diffuse Noxious Inhibitory Control (DNIC) or Conditioned Pain Modulation (CPM))

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does a second noxious stimulus lead to?

A

Activation of the PAG, nRM and RVM in the brainstem, which results in diffuse analgesic effect over the rest of the body
“Pain inhibits pain”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are interneurons in the dorsal horn of the spinal cord activated by?

A

5-HT/NE and release endogenous opiates (enkephalin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does enkephalin in the dorsal horn inhibit?

A

the first-order and second-order neurons (nociceptive
specific and/or WDR neurons)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

____________ is the selective suppression of pain without effects on consciousness or other sensations

A

Analgesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are mechanisms to achieve pain relief?

A
  1. Pharmacological agents: COX Inhibitors (aspirin,
    ibuprofen), Opioids, Antidepressants (TCAs),
    Anticonvulsants (GABApentin), Topical Lidocaine &
    Capsaicin
  2. Massage (Gate Control Theory of Pain)
  3. Acupuncture (seems to be linked to activation of the
    endogenous opioid pathways)
  4. Transcutaneous Electrical Stimulation (TENS)
  5. Nerve Blocks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is pain information from the orofacial region conveyed into the CNS?

A

Via the Trigeminospinothalamic Tract and the
Trigeminoreticular Tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Pain can be referred to the orofacial region (particularly
teeth) in response to:

A
  • Maxillary Sinusitis
  • Angina
  • Migraine
  • Nasal Mucosa
  • Ear Pain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why is dental pain exaggerated pain even with mild inflammation?

A

Dentin and enamel has limited space to swell in the inflammatory
state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What stimuli do not cause pain in an uninflamted healthy tooth and why?

A

Noxious hot/cold stimuli due to thermal insulating of the enamel
But, with missing enamel and exposed dentin, a slight thermal
stimuli will cause sudden and stinging pain

18
Q

What air puffs to exposed dentin result in intesnse pain? and how would this manifest on skin?

A

Weak air puffs; on skin this would result in the sensation of light touch

19
Q

Describe the nerve branching of teeth

A

While afferent fibers innervating teeth comprise only 0.1% of trigeminal
neurons, each of these fibers has extensive branching, such that each
afferent nerve innervates multiple teeth

20
Q

Large receptive fields =

A

Poor localization

21
Q

Why is dentin sensitive?

A

Due to dentinal tubules
- nerve fibers penetrate the dentinal tubules, but only for a short distance into the inner dentin

22
Q

What do odontoblasts have?

A

Long processes that are located in the dentinal tubule and their cell body is on the surface of the dental pulp

23
Q

Nociceptors in tooth pulp are highly _____

A

Vascular; contains many neurons, but is a low-
compliance tissue because it is surrounded by hard tissue

24
Q

Any change in volume within tooth pulp translates to?

A

Large changes in pressure
a. Inflammation due to mechanical or bacterial trauma
b. Increases in pulpal temperature secondary to laser radiation
c. Can lead to hypoxia and eventually tissue necrosis

25
Q

Dentin is a _______, ______ tissue

A

Mineralized; avascular

26
Q

What is dentin suprasensitive to?

A

Extreme temperatures, particularly at the neck of the tooth (gingival recession, wear of cementum and enamel)

27
Q

What is dentin sensitive to?

A

Hyperosmotic solutions

28
Q

What is dentin NOT sensitive to?

A

KCl, bradykinin, and histamine

29
Q

What do dentinal tubules contain?

A

Odontoblasts and perhaps also nerve terminals

30
Q

Dentinal and pulp nociceptor information travels via

A

Alpha delta and C fibers along with alpha beta
- the nerve fibers in tooth pulp are ~90% C-fibers

31
Q

What does dentinal pain result as?

A

Sharp pain via alpha delta fibers

32
Q

What does pulp pain result as?

A

Dull/achey pain via C-fibers

33
Q

How are dentin and pulp separated?

A

By tight junctions between epithelial cells - selectively permeable barrier

34
Q

What are the three hypotheses for dental nociception?

A

A. Neural theory
B. Hydrodynamic theory
C. Odontoblast transducer theory

35
Q

What is the neural theory?

A

Free nerve endings in
dentinal tubules are activated

36
Q

What is the hydrodynamic theory?

A

Stimulus displaces fluid
in dentinal tubules
which activates
mechanoreceptors in
nerve endings of dentin
or pulp

37
Q

What is the odontoblast transducer theory?

A

Odontoblasts are excited and transduce the signal to nearby nerve cells

38
Q

What are the receptors associated with dental primary afferent nerve fibers?

A

TRPV1
- Polymodal receptor activated by painful
chemicals (Capsaicin) and noxious temperatures (above 42°C)
TRPM8
- Low Temperature (threshold 25°C)
TRPA1
- Low Temperature (threshold 17°C)

39
Q

Not all dental pains are due to __________

A

Noxious temperatures (ex: water spray, puff of air, sweet substances, etc)

40
Q

What receptors does the PDL have?

A

Nociceptors AND ruffini endings (a mechanoreceptor/proprioceptor)

41
Q

Periodontal nociceptive information from free nerve endings travels via?

A

Alpha delta/C fibers

42
Q

The periodontal mechanoreceptors (Ruffini endings) regulate?

A

The forces applied by the
teeth in occlusion, mastication and biting.
These receptors are slowly adapting, show
directional sensitivity and their response
varies with the force applied to the tooth

D1 Spring - Physiology (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions