Trigeminal System (6/30/15)

Question 1

What is Chemesthesis?

Answer 1

Trigeminal fibers can be activated by some chemical stimuli including spices.

Question 2

What is Stereognosis?

Answer 2

the 3-dimensionality of objects in the mouth.

Question 3

What is flavor?

Answer 3

taste, olfaction and texture.

Question 4

Describe the 3 main branches of the Trigeminal nerve…

Answer 4

• Ophthalmic = sensory only
• Maxillary = sensory only
• Mandibular = sensory and motor!

*There are 16 major nerve branches and 53 named branches.

Question 5

The cell bodies of the trigeminal nerve located in the ______.

Answer 5

Trigeminal ganglion (gassenrian/semilunar)

Question 6

After entering the brain at the level of the pons the fibers bifurcate into _____ and _______ branches.

Answer 6

Ascending and descending branches.

Question 7

Ascending branches end in the ____ and function primarily as ______.

Answer 7

Principal nucleus

Light touch.

Question 8

Descending branches end in the ______ and has 3 divisions called____, _____ and _____.

Answer 8

Spinal trigeminal nucleus
Nucleus Oralis = light touch
Nucleus interpolaris = temp perception
Nucleus Caudalis = pain perception

Question 9

The somatopic representation of the head and neck is organized within the _____, ______ and _______.

Answer 9

Sub nucleus of the brainstem, the thalamus and in the parietal lobe.

Question 10

The face is represented in the _______ primary somatosensory cortex.

Answer 10

Lateral

Question 11

How are peripheral nerves classified?

Answer 11

Based on size, conduction velocity, threshold and modality (what they respond to)

Question 12

A- Beta (Muscle type? Threshold? Modality?)

Answer 12

Muscle type = 1 and 2
Threshold = Low
Modality = Touch and Proprioceptive

Question 13

A- Delta ( Muscle Type? Threshold? Modality?)

Answer 13

Muscle type = 3
Threshold = high
Modality = Touch, Temp, Chemesthesis and Sharp pain

Question 14

C-Fiber (Muscle Type? Threshold? Modality?)

Answer 14

Muscle Type = 4
Threshold = Highest
Modality = Temp, Chemesthesis and Dull/burning pain

Question 15

What are the 4 types of mechanoreceptors?

Answer 15

Rapid adapting mechanoreceptors
Slow adapting Mechanoreceptors
* small and large receptive fields for each

Question 16

How does transduction occur for Mechanoreceptors?

Answer 16

deformation or stretch of the axon membrane that opens Na channels, thereby depolarizing the axon and causing AP’s.

Question 17

Mechanical transduction can also occur through _______ .

Answer 17

Transient Receptor Potential Channels (Piezzo 1 and 2)

Question 18

Miessner corpuscle?

Answer 18

RA Light touch/spatial discrimination

Question 19

Merkel Receptor?

Answer 19

SA I Pressure

Question 20

Ruffini Corpuscle?

Answer 20

SA II Skin stretch

Question 21

Pacinian Corpuscle?

Answer 21

RA II Vibration

Question 22

The Response properties of mechanoreceptors are influenced by what 3 sources?

Answer 22

1. The degree of mylenation
2. Location of the receptor (Superficial or deep)
3. The structure of the ending (Encapsulation)

Question 23

Pacinian corpuscles respond to ___ and ____.

Answer 23

Stimuli start and cessation

Question 24

What are Von Frey hairs?

Answer 24

Monofilaments used to measure (in grams) touch thresholds.

Question 25

The closer you get to the midline of the face.....

Answer 25

the lower the threshold for 2 point touch discrimination (it gets better)

Question 26

Oral have different anatomical receptor types than are found in the hand. T or F?

Answer 26

True. There are no RA II (Pacinian) receptors in the face et many RA I, SA I and II.

Question 27

What is Microneurography?

Answer 27

Technique used to record nerve impulses.

Question 28

What are the most common receptors in the tongue (Lingual branch of mandibular nerve)?

Answer 28

Coiled nerve endings (Krause bulbs) look similar to meissners corpuscles in the hand.

Question 29

At the tip of the tongue, the receptive fields are ______.

Answer 29

Small

Question 30

What are some origins of trigeminal dysfunction?

Answer 30

- Oral and facial trauma - Complete dentures with loss of underlying tissue - infectious diseases - dental and surgical procedures, tooth extraction and osteotomy

Question 31

TMJ Receptors help mediate _____.

Answer 31

Interdental sensation

Question 32

What is the innervation of TMJ?

Answer 32

- auriculotemporal | - master and posterior deep temporal branch of trigeminal nerve.

Question 33

Where is the innervation most dense in the TMJ?

Answer 33

Posterior and Lateral position of the capsule.

Question 34

____ teeth are more sensitive.

Answer 34

Anterior

Question 35

What is the innervation of the PDL's?

Answer 35

branches of superior and inferior alveolar nerves. * A very different type of ending is found in the PDL compared to the tongue mostly the UNENCAPSULATED RUFFINI TYPE ENDINGS.

Question 36

______ is relatively superficial in the PDL compared to the _____.

Answer 36

``` Trigeminal Ganglion Mesencephalic nucleus (More innervation at apex) ```

Question 37

When force is directed to the tooth from a _____ direction the response is largest.

Answer 37

distal

Question 38

As a stimulus is applied more rapidly, the response latency is ______.

Answer 38

Shorter.

Question 39

sub nucleus oralis projects to ______ to produce a __________.

Answer 39

Motor trigeminal nucleus to produces a jaw opending reflex via nat. digastric muscle.

Question 40

_______ projections can cause salivary secretions.

Answer 40

Mesencephalic trigeminal nucleus

Question 41

Studies indicate that both the ____ and _____ contribute to the interdental sensitivity.

Answer 41

PDL and TMJ

Question 42

In reguards to temp, there is a ____ variation for warmth and ____ variation for cold.

Answer 42

Wide variation for warmth | Less variation for cold ( usually perceived more intense than warmth)

Question 43

There are ____ subfamilies of Transient Receptor potential channels. comprised of _____ transmembrane domains with a cation channel between ____ and ___ domains.

Answer 43

8 sub families 6 domains between 5th and 6th domains

Question 44

TRPV1

Answer 44

temp >42 (Capsaicin and ethanol)

Question 45

TRPV2

Answer 45

temp >52

Question 46

TRPV3

Answer 46

temp 34-38 (camphor)

Question 47

TRPV4

Answer 47

temp 27-34

Question 48

TRPM8

Answer 48

Temp

Question 49

TRPA1

Answer 49

Temp