EX1; Trigeminal System Flashcards Preview

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Flashcards in EX1; Trigeminal System Deck (65)
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1
Q

What is the functional significance of the trigeminal system

A

speech production; positioning tongue for articulation
positioning food for chewing efficacy
salvation

2
Q

What is stereognosis regarding the trigeminal system

A

3-dimensionality of objects in the mouth

size, texture, hardness

3
Q

what is flavor regarding the trigeminal system

A

taste and olfaction (special senses)

texture, temperature, chemesthesis

4
Q

What sensations are evoked in the mouth and perioral region regarding trigeminal

A

touch
temperature
pain
proprioception info regarding the position of the tongue and jaws

5
Q

Trigeminal fibers can be activated by some chemical stimuli including spices, high concentrations of acid/salt, and some compounds common in dentistry; this is termed what

A

chemesthesis

6
Q

What are the three main branches of trigeminal

A

opthalmic
maxillary
mandibular

7
Q

Which main branch contains both motor and sensory, as opposed to just sensory

A

mandibular

8
Q

Where are the cell bodies for the trigeminal nerve located

A

in the trigeminal (semi-lunar/Gasserian) ganglia in the temporal bone

9
Q

At which level of the brain do fibers (axons) of the trigeminal nerve enter and bifurcate into ascending and descending branches ultimately terminating in different brainstem structures with different functions

A

pons

10
Q

The ascending branch of trigeminal ends where

A

in the principal nucleus

11
Q

What is the function of the ascending branch of trigeminal

A

light touch perception

12
Q

The descending branch of trigeminal ends where

A

in the spinal trigeminal nucleus

13
Q

What are the three divisions of the spinal trigeminal nucleus

A

nucleus oralis
nucleus interpolaris
nucleus caudalis

14
Q

What is the function of nucleus oralis

A

light touch perception

15
Q

What is the function of nucleus interpolaris

A

temperature perception

16
Q

What is the function of nucleus caudalis

A

pain perception

17
Q

The representation of the head and neck is somatotopically organized within each sensory nucleus and sub nucleus in the brainstem, what are these

A

thalamus
ventral posterior medial nucleus
somatosensory cortex in the parietal lobe

18
Q

What five things can peripheral nerve fibers be classified as

A
fiber size
conduction velocity
threshold
modality (what they respond to)
type of receptors at the end of the sensory axon
19
Q

What are the two types of rapidly adapting mechanoreceptors

A

small receptive fields

large receptive fields

20
Q

What are the two types of slowly adapting mecahnoreceptors

A

small receptive fields

large receptive fields

21
Q

This is the deformation or stretch of the axon membrane that opens Na channels, they by polarizing the axon and causing impulses (action potentials)

A

transduction

22
Q

Recent studies suggest that these sodium channels influencing transduction belong to which super family

A

epithelial NaCl channels; ENac

23
Q

Mechanical transduction may occur through which specific channels

A

transient receptor potential channels

24
Q

In the hand, there is a correlation between receptor what

A

structure and function

25
Q

The Ruffini corpuscle (type II SA) is involved with what sensation

A

skin stretch

26
Q

The pacinian corpuscle is involved with what sensation

A

vibration

27
Q

The response properties of mechanoreceptors are influenced by three sources

A

degree of myelination
location of receptor (superficial/deep)
structure of the ending (meissner, ruffini, etc)

28
Q

The Meissner corpuscle is involved with what sensation

A

light touch/spatial discrimination

29
Q

The merkel receptor is involved with what sensation

A

pressure

30
Q

This receptor ending is surrounded by layers of Schwann cells and collagen

A

pacinian

31
Q

When a stimulus is applied to pacinian corpuscles the lamellae resist the force such that only what occurs

A

the initial impact of the stimulus makes it to the transduction site

32
Q

When the force is removed from the pacinian corpuscle compressed lamellae imparts what

A

an off-response to the receptor

33
Q

These are monofilaments calibrated to bend at specific forces, usually measured in grams; used to establish touch tresholds

A

von frey hairs

34
Q

Which portion of the face has a lower threshold for two-point discrimination

A

facial midline

35
Q

Oral and facial tissues show specialized patterns of what

A

innervation and in some instances different anatomical receptor types than are found in the hand

36
Q

This is the recording from human nerves; map of receptive fields; determines neuron properties

A

microneurography

37
Q

True or False

Females are typically more two point discrimination sensitive than males

A

True

38
Q

The infraorbital nerve does not contain these fibers, and what does this mean

A

no RAII or Pacinian corpuscles
we can still feel vibration on our face, the receptor in the hand is thought to mediate this (low vibrotactile sensitivity)

39
Q

The tongue is innervated by this mandibular nerve, although sensitive, there is not a large varies of receptor endings

A

lingual nerve

40
Q

What is the most common type of receptor endings in the lingual nerve

A

non-encapsulated “coiled nerve endings” referred to as Krause end bulbs

41
Q

What type of responses are recorded in the tongue

A

rapidly adapting (RA)
slowly adapting (SA)
which is one of a kind, especially regarding to its ending
*high degree of sensitivity

42
Q

What two things do Krause end bulbs and Meissner corpuscles have in common

A

high density and small receipting field at tip

both have rapidly and slowly adapting responses

43
Q

What are four things affecting the origin of trigeminal dysfunction

A

oral and facial trauma
complete dentures with loss of underlying tissue
infectious disease (periodontitis)
dental and surgical procedures

44
Q

True or False
There is much documentation about the mechanoreceptors in the TMJ and evidence indicated these receptors help mediate interdental sensation

A

False; there is little evidence, but they do mediate interdental sensation

45
Q

What branches of mandibualr; trigeminal innervate TMJ

A

auriculotemporal
masseter
posterior deep temporal

46
Q

Where is the most dense innervation of TMJ

A

posterior and lateral portion of capsule

47
Q

What types of nerve endings are found in TMJ

A

free nerve endings (C-fibers) predominate with only a few specialized endings such as refine endings or golgi tendon organs

48
Q

Which teeth are more sensitive based upon pressure applied using von frey hairs

A

midline teeth

49
Q

What is impacted most with trigeminal disfunction following third molar extraction

A

the lip is impacted the most; can lead to tongue biting and hot burns

50
Q

What nerve innervate the PDL

A

branches of superior and inferior alveolar nerves

51
Q

What type of nerve ending is found in the PDL

A

unencapsulated Ruffini type endings

52
Q

What nuclei and ganglia send fibers to innervate the PDL; they may play a role in different functions

A

trigeminal ganglion

mesencephalic nucleus

53
Q

Directional sensitivity of the PDL shows that when forces are directed to the tooth from this direction, the response is the largest

A

distal direction

54
Q

These specific fibers also show directional sensitivity

A

rapidly adapting

55
Q

These connections are part of the ascending sensory pathway that leads to conscious perception via the principal trigeminal nucleus that projects to the VPM in the thalamus and then o the somatosensory cortex

A

trigeminal ganglion

56
Q

Trigeminal ganglion fibers also project to sub nucleus orals, which then projects to motor trigeminal nucleus to produce what

A

jaw opening reflex via the anterior digastric muscle

57
Q

These projections can cause salivary secretion via connections to the brainstem salivary nuclei

A

mesencephalic trigeminal nucleus

58
Q

An example of rapidly adapting response is as the stimulus is applied more rapidly, what happens to the response latency

A

it becomes shorter

59
Q

clincial conditions such as periodontitis can increase what of PDL

A

increase thresholds (lower sensitivity)

60
Q

The location of what in the PDL determines sensitivity

A

Ruffini endings

61
Q

Denture and implant patients have trouble with force regarding what

A

they have trouble controlling force but do not have trouble generating force

62
Q

There is a wide/narrow variation in the perception of warmth in and around the oral and facial regions

A

wide

63
Q

There is more/less variation for cold sensation of which is generally perceived more intensely than warmth

A

less

64
Q

Temperature sensitive fibers typical respond to a range of stimuli classified as what depending on the peak response

A

cold or warm

65
Q

Many of the different these receptors respond to temperature and some receptors also respond to specific chemical stimuli

A

TRP (transient receptor potential)