trigeminal

Question 1

the ascending branch of the trigeminal n. ends in _____, which functions primarily for _____

Answer 1

primary sensory nucleus (main/chief/pontine); light touch perception

Question 2

the descending branch of the trigeminal n. ends in the ____ which has 3 subdivisions:

Answer 2

ends in spinal trigeminal nucleus
3 divisions: nucleus oralis (light touch perception)
nucleus interpolaris (temperature)
nucleus caudalis (pain)

Question 3

there are two types of ____ mechanoreceptors and two types of ____ mechanoreceptors

Answer 3

rapidly adapting; slowly adapting

Question 4

____ for mechanoreception is the deformation or stretch of the axon membrane that opens ____ channels, thereby depolarizing the axon and causing impulses

Answer 4

transduction; sodium

Question 5

type of sodium channel involved in mechanoreception

Answer 5

epithelial NaCl channels

Question 6

mechanoreception may also occur thru specific ______ channels, an example of which are piezo 1 and piezo 2

Answer 6

transient receptor potential (TRP)

Question 7

in the ____, there is a correlation between receptor structure and function

Answer 7

hand

Question 8

response properties of mechanoreceptors are influenced by:

Answer 8

1. degree of myelination
2. location of the receptor (superficial/deep)
3. structure of the ending (degree of encapsulation)(Meissner/Ruffini)
4. transduction

Question 9

pacinian corpuscles are designed to detect ____ stimuli

Answer 9

vibratory

Question 10

2 types of superficial endings

Answer 10

meissner’s corpuscles and merkel disc

Question 11

2 types of deep endings

Answer 11

pacinian corpuscle and ruffini ending

Question 12

4 types of endings and their types

Answer 12

meissner corpuscle (RAI)
pacinian corpuscle (RAII)
merkel disc (SAI)
ruffini ending (SAII)

Question 13

4 types of endings and what they detect

Answer 13

meissner corpuscle- light touch/spatial discrimination
pacinian corpuscle- vibration
merkel disc- pressure
ruffini ending- skin stretch

Question 14

lamellae of pacinian corpuscles are composed of ____ and ____ separated by ___ to provide a cushion to applied stimulus

Answer 14

cells; collagen fibers; fluid

Question 15

upon release of stimulus, ____ of pacinian corpuscle imparts a ____ response to nerve ending

Answer 15

decompression; 2nd (off)

Question 16

mechanisms of mechanotransduction

Answer 16

1. ENaC (epithelial Na channels)
2. TRP channels
3. Piezo1 and Piezo2

Question 17

____ are used to measure two-point discrimination (tactile sensitivity)

Answer 17

disks

Question 18

____ are monofilaments calibrated to bend at specific forces, usually measured in grams

Answer 18

von frey hairs (semmes-weinstein monofilaments)

Question 19

von frey hairs are used to establish ____

Answer 19

touch thresholds

Question 20

facial ____ structures have a lower threshold for two-point discrimination

Answer 20

midline

Question 21

the technique of _____ can be used to record nerve impulses from the infraorbital nerve innervating the facial region in human subjects

Answer 21

microneurography

Question 22

there are no ____ type responses or ____ in the face (but this receptor type is present in the hand)

Answer 22

RA II; Pacian corpuscle

Question 23

lack of pacinian corpuscles leads to low ____ sensitivity of the face

Answer 23

vibrotactile

Question 24

____ endings predominate in the tongue

Answer 24

unencapsulated

Question 25

the most common type of receptor ending in the tongue is the ____ which looks very similar to _____ in the hand

Answer 25

Krause end bulbs (non-encapsulated “coiled nerve endings”); meissner corpuscle

Question 26

the tongue has both rapidly and slowly adapting mechanoreceptors despite:

Answer 26

having only one kind of ending (compared to the hand)

Question 27

there is ____ of ____receptive fields at the tip of the tongue

Answer 27

high density; small

Question 28

on the face, the ____ have the lowest two point thresholds

Answer 28

lips

Question 29

the ____ and ____ nerves can sometimes be damaged during 3rd molar extraction

Answer 29

lingual; mental

Question 30

origins of trigeminal dysfunction

Answer 30

oral and facial trauma
complete dentures with loss of underlying tissues
infectious diseases (periodontitis)
dental and surgical procedures (tooth extraction and osteotomy)

Question 31

merkel cells are found in ____, ____ and _____

Answer 31

buccal mucosa; gingiva; palate

Question 32

merkel cells contain ____ and ____ that can promote cell division

Answer 32

peptides; growth factors

Question 33

merkel cells are found in areas with ______; there are more MCs in ____ patients that use soft tissues for chewing

Answer 33

high masticatory load (i.e. tissues subject to mechanical stress); edentulous

Question 34

studies indicate that receptors found in the TMJ help mediate _____

Answer 34

interdental sensation

Question 35

innervation of TMJ

Answer 35

auriculotemporal, masseteric, and posterior deep temporal branch of the trigeminal n.

Question 36

there is dense innervation of ____ and ____ portions of TMJ capsule

Answer 36

posterior; lateral

Question 37

_____ predominate in the TMJ with only a few specialized endings such as ____ or ____

Answer 37

free nerve endings; Ruffini endings; golgi tendon organs

Question 38

innervation of the PDL

Answer 38

branches of superior and inferior alveolar nerves

Question 39

most abundant type of ending found in the PDL

Answer 39

unencapsulated ruffini type endings

Question 40

TMJ mechanoreceptors are innervated by ____, mostly ____

Answer 40

mandibular branch; auriculotemporal

Question 41

location of ____ in PDL determines sensitivity

Answer 41

Ruffini ending

Question 42

PDL receptor function

Answer 42

• detect force to teeth
• interdental discrimination
• stereognosis
• jaw reflexes
• salivation

Question 43

trigeminal ganglion connections are part of the ascending sensory pathway that leads to _____ via the principal trigeminal nucleus that projects to ____ and then to _____

Answer 43

conscious perception; VPM in the thalamus; somatosensory cortex

Question 44

some TG fibers project to subnucleus oralis which then projects to the ____ to produce a _____ reflex via the anterior digastric muscle

Answer 44

motor trigeminal nucleus; jaw-opening

Question 45

mesencephalic trigeminal nucleus projections can cause ____ via connections to the _____

Answer 45

salivation; brainstem salivary nuclei

Question 46

for warm sensitivity- ____ is least sensitive of intra-oral tissues

Answer 46

buccal mucosa