Oro-Facial Flashcards
1
Q
What are the factors affecting taste perception?
A
Age Meals Hunger Smoking Obesity Pregnancy Cold/Flu/Allergies Disease Temperature Adaptation
2
Q
What is the main component of umami taste?
A
L-Glutamate
3
Q
What is the main component of bitter tastes?
A
Alkaloids
4
Q
Sensory pathways for taste in the epiglottis and larynx is innervated by what cranial nerve?
A
CN X: Vagus
5
Q
Glossopharyngeal nerve provides taste to what?
A
Posterior 1/3 of tongue and pharynx
6
Q
Where do taste signals terminate in the brain?
A
Gustatory Cortex (Anterior Insulafrontal Operculum)
7
Q
What are the two measurements for taste acuity?
A
Detection and Recognition Threshold
8
Q
T/F Sweet taste is pleasant at low concentrations
A
False
9
Q
What is the life span of sustentacular + taste cells?
A
1-2 weeks
10
Q
What is the implication of taste for obese people?
A
Less taste cells > compromised fat sensing system > delays satiety response > excess food intake
11
Q
What is the difference between ageusia and dysgeusia?
A
Ageusia: total loss of taste
Dysgeusia: partial loss of taste
12
Q
Damage to the chorda tympani will result in unilateral or contralateral loss of taste?
A
Unilateral loss of taste to anterior 2/3rd of the tongue
13
Q
What can’t the Gates Control Theory explain?
A
Phantom Pain
14
Q
T/F: Tonic Receptors are fast adapting
A
F: Slow Adapting
15
Q
What are 5 things chemoreceptors can detect?
A
Taste / Smell / pH (H+) / Plasma O2 / Osmolality
16
Q
What do Teleceptors detect and give 2 examples
A
Teleceptors are sensitive to stimuli originating at a distance. Such nerve endings exist in the eyes and ears.
17
Q
Interoceptors can be found where?
A
Inside the body, in muscles, tendons and joints such as Muscle Spindles or the TMJ
18
Q
Where in the Dorsal Column do neurons cross over?
A
Decusation of Media Leminscus in the medulla oblongata
19
Q
Where do neurons cross over in the Spinothalamic Tract?
A
Within the spinal column where the 1st order neuron exists
20
Q
What sort of sensory input can be found from nerves in the dorsal column?
A
Fine touch + pressure, vibration, position sensations
21
Q
What sort of sensory input can be found from nerves in the spinothalamic tract?
A
Pain, Temperature, Crude Touch/Pressure, Tickle/Itch, Sexual sensations
22
Q
What is meant by Somatic Sensory Projection?
A
Body parts represented in the brain is proportional to it’s importance for that species.
Eg: for humans sensory input from fingers + tongue is paramount for speech and fine motor skills
23
Q
Meissner Corpuscle measure what sensory input?
A
Dynamic Deformation
24
Q
Hair Follicles measure what sensory input?
A
Light Touch
25
Pacinian Corpuscle measure what sensory input?
Vibration
26
Merkel Cell measure what sensory input?
Indentation & Depth
27
Ruffini Corpuscle measure what sensory input?
Stretch
28
C-Fibre LTM measure what sensory input?
Touch
29
Mechano-Nociceptor Polymodal Mechano-Nociceptors measure what sensory input?
Injuring Forces
30
What is meant by Tactile Acuity?
Two points of contact are felt as two distinct points
31
Can Tactile Acuity cross the midline?
No
32
What are some examples of Tactile Acuity
Tongue, Finger Tip, Nose
33
What mucosa in the oral cavity can detect both cold and warm?
```
Dorsum of Tongue (Strong Both)
Ventral Tongue (Moderate Warm/Strong Cold)
Labial Mucosa (Moderate Both)
```
34
What is the role of Periodontal Mechanoreceptors?
Oral Stereognosis and tactile sensitivity to teeth
35
What factors affect Oral Stereognosis Ability (OSA)?
- Form, Size and Surface characteristics of the test piece
- Presentation order of the objects
- Age
- Dental Status (poorer with missing dentition, perio, endo treated teeth)
- Duchenne Muscular Dystrophy
36
Why is Oral Stereognosis important?
For efficient mastication that does not damage hard / soft tissue
37
Stomatodynia is also known as what?
Burning Mouth Syndrome
38
What are endogenous mediators of pain for nociceptors?
Bradykinin, H+, Substance P, Histamine, K+
39
What fibres result in fast pain?
A-Delta Fibres
40
What is double pain sensation?
A-Delta + C Fibres which conduct the impulses at different velocities
41
In an inflammatory response what does bradykinin do in terms of pain?
Activates nociceptors
42
What is Central Sensitisation?
Where the nervous system winds up during a persistent state of high reactivity to pain in order to develop a response to maintain chronic pain. This results in the patient being more sensitive not only to pain but to other sensory input.
43
What is the role of Substance P during the inflammation of dental pulp?
```
Vasodilatory Response
Histamine Release
Increase in blood flow + vascular permeability
Increase in blood pressure
Synthesis of proinflammatory cytokines
Chemotaxis of inflammatory cells
Sensitisation of nociceptors
```
44
What can modulate pain from ascending pain transmitting tracts?
Endogenous Opiates from Inhibitory interneurons in the dorsal horn
45
Are A-Beta fibres part of a pain response?
No.
They are large myelinated fibres involved with touch, pressure and proprioception
46
What are Von Ebner's Glands and where are they found?
Serous salivary secretion glands found on the lateral surface of Circumvallate Papillae
47
If a patient is clinically observed with a lack of Filliform Papillae and a bold red appearance, what could this be a sign of?
Low Iron levels in the blood
48
Where can minor taste organs be found?
Soft + Hard Palate
Pharynx
Larynx
Epiglottis
49
What is the difference between detection and recongition threshold?
Detection Threshold: the ability to distinguish a taste apart from a drop of water
Recognition Threshold: the concentration needed for a solution to be identified as having a certain taste
50
Why does xerostomia result in poor taste
Poor saliva results in insufficient solution to transport
51
What are 3 main reasons for taste disorders?
1. Transport Loss (Xerostomia)
2. Sensory Loss (Injury to receptor cells)
3. Neural Loss ( gustatory afferent nerves + central gustatory pathways)
52
What are 4 key criteria for the detection of olfactory stimuli?
- Must by volatile - sensitive to changing stimulus
- Sufficiently water soluble
- Must be lipid soluble
- Minimum number of odorous particles must be present for a minimum length of time
53
What are the 3 phases of the masticatory cycle?
- Opening Phase (Slow > Fast)
- Closing Phase (Fast > Slow)
- Occlusal Phase
54
What masticatory features would you expect to see in a true carnivore?
- Cylindric TMJ for strong biting hinge movement
- Sharp Teeth
- Fast Muscles
- Dominant Temporalis
55
What masticatory features would you expect to see in a true herbivore?
- Saucer like TMJ for grinding fibrous food
- Flat Teeth
- Slow Muscles
- Dominant Masseter
56
What is the role of the Orbicularis Oris in mastication?
To provide an anterior oral seal around the lips
57
Accessory muscles of mastication Sternohyoid, Sternothyroid, Omohyoid are innervated by what?
C1–C3 Ansa cervicalis
58
A low innervation ratio for a motor unit is indicative of what?
Low levels of control over a muscle
59
What 5 types of receptors are responsible for neural control of neural control of the jaw?
1. Muscle Spindles
2. Tendon Organ Receptors
3. TMJ Receptors
4. Skin / Mucosal Receptors
5. PDL Mechanoreceptors
60
In which muscles of mastication would we expect to see many muscle spindles?
Temporalis, Masseter, Medial Pterygoid Muscle (Jaw Closers) - stretch of muscles is important in maintaining sense of space
61
What are the 2 possible actions of an effector in a reflex arc?
1. Muscle Contraction
| 2. Gland Secretion
62
What would be a trigger for a jaw-opening reflex?
Fishbone wedged in gingiva
63
What would be a trigger for a jaw-closing reflex?
During running/jumping
| Biting on a nut - adjusted less pressure on close
64
What receptors are responsible for jaw-closing reflexes?
Muscle Spindles in jaw-closer muscles (temporalis, medial pterygoid, masseter)
65
What receptors are responsible for jaw-opening reflexes?
High-Threshold mechanoreceptors + nociceptors in PDL, gingiva, oral mucosa, tongue, lips, facial skin, nociceptors in tooth pulp
66
Is Jaw Closing reflex bilateral or unilateral?
Unilateral
67
T/F Periodontal Reflexes only have reflex inhibition to jaw-closer muscles?
False, they have both
1. Reflex inhibition of jaw-closer muscles - on tapping on a tooth, rapid increase in load force (Protective role: eg stone in sandwich)
2. Reflex excitation of jaw-closer muscles - o n weak pressure to tooth
(Help guide food into occlusion, coordinate chewing, crushing of food)
68
With the Peripheral Input + Cortical Input + Central Pattern Generator model for mastication, what is a practical example of when there is a lack of peripheral input?
When a patient is eating whilst under LA - Lack of peripheral feedback generates inefficient and dangerous masticatory strokes possibly leading to soft tissue damage
69
Where in the brain is swallowing controlled?
The swallowing centre in the pons and medulla oblongata
70
What are the 4 phases of swallowing?
1. Preparatory / Masticatory Phase
2. Buccal/Oral Phase
3. Pharyngeal Phase
4. Oesophageal Phase
71
What is the Buccal/Oral Phase of swallowing?
Tongue collects food and pushes it back towards the oropharynx
72
What occurs during the Pharyngeal phase of swallowing?
- Contact of bolus with mechanoreceptors in the pharynx/larynx signals swallowing centre
- Respiration inhibited
- Soft Palate Elevated to seal nasal cavity
- Glottis closes and vocal cords seal entrance to trachea
- Epiglottis tilts backwards to cover glottis
- Larynx is elevated prevent entry of food (involuntary movement)
73
What occurs during the Oesophageal Phase of swallowing?
- Pharyngo-oesophageal sphincter opens when food/liquid passes
- Glottis re-opens and breathing resumes
- Food then propelled by peristalsis motion down oesophagus
74
What are the 4 suprahyoid muscles?
The suprahyoid muscles are four muscles located above the hyoid bone in the neck. They are the digastric, stylohyoid, geniohyoid, and mylohyoid muscles
75
What are the 3 infrahyoid muscles?
Thyrohyoid
Sternohyoid
Omohyoid
76
What are the 2 main roles of the digastric muscles?
- Assists Lateral Pterygoid in jaw opening
| - Regulating the position of the hyoid bone
77
What does the mylohyoid muscle assist in ?
- Regulating the position of the hyoid bone
| - Tongue Movements
78
Which muscle of mastication is most commonly associated with TMD?
Temporalis
79
What movements are associated with the Lateral Pterygoid Muscle?
Jaw Opening
Jaw Protrusion
Contralateral Jaw Movements
80
What are the 2 heads of the Lateral Pterygoid?
Inferior Head of Lateral Pterygoid (IHLP)
| Superior Head of Lateral Pterygoid (SHLP)
81
What are the 2 functions of the Medial Pterygoid Muscle?
Elevates Mandible
| Assists Lateral Pterygoid in moving jaw side-to-side
82
What are the 2 parts of the Masseter Muscle?
Superficial and Deep masseter
83
T/F Superficial masseter is more active than Deep Masseter
F: Deep Masseter is primarily engaged during mastication + intercuspal open/close excursions
84
What Muscle Fibre Types are more suitable for postural tasks?
S-Type (Slow Contracting)
85
What Muscle Fibre Types are more suitable for strong and rapid tasks
F-Types (Fast Contracting)
86
What type of muscles of mastication are designed to produce velocity and displacement?
Jaw Closers
87
What type of muscles of mastication are designed to produce force?
Jaw Openers
88
What is the motion of the temporalis
Elevates and retrudes the mandible at the TMJ
89
What are the motions of the Inferior Head of Lateral Pterygoid (IHLP)?
Jaw Opening
Jaw Protrusion
Contralateral Jaw Movements
90
When is the superficial part of the masseter most active?
During Incisal Clenching
91
T/F: The Superficial Masseter is always more active than the Deep Masseter
False, Deep masseter on both sides is always more
| active than superficial masseter
92
What are the features of S Motor Units?
Slow Contracting
| Fatigue-Resistant
93
What are the features of Fine Motor Units?
Fast Contracting
| Intermediate Fatigable
94
F-Type Motor Units are more suited to what sort of tasks?
Strong and Rapid Bite Tasks
95
S-Type Motor Units are more suited to what sort of tasks?
Postural Tasks
96
Which muscle fibres are the best for twitch speed?
FF
97
Which muscle fibres are the best for twitch strength?
FF
98
Which muscle fibres are the best for resisting fatigue?
S
99
Which muscle fibres have the most motoneurons?
FF
100
Which muscle fibres are activated first?
S
101
Which muscle fibres have the most powerful contractions?
FF
102
What is the significance of hybrid Myosin Heavy Chain fibres?
Jaw muscles do a large variety of motor tasks (biting, mastication, swallowing, speech, singing, yawning) &
require a diversity of forces
103
What are 5 factors affecting the fibre-type composition in jaw muscles
- Age
- Hormones
- Food - hardness
- Adaptation behaviours - dentures, edentulousness
- Craniofacial Morphology (long face, open bite)
104
What are the 5 steps of initiating muscle contraction?
1. ACh released at the neuromuscular junction. Binds to Receptors
2. Action potential reaches T Tubules
3. Sarcoplasmic reticulum releases Ca2+
4. Active site is exposed, Cross-Bridge formation
5. Contraction begins
105
Precise movement is possibly with what sort of motor neuron?
Small Motor Neurons
106
T/F: Larger Motor Neurons are fatigue resistant
False
107
What mechanoreceptors are primarily involved during chewing?
Periodontal Mechanoreceptors (PMRs) generate input to 80% of muscle activity for chewinb
108
What is Fremitus?
Fremitus: a vibration perceptible on palpation; in dentistry, a vibration palpable when the teeth come into contact. This is pathological based on occlusal damage from parafunction or bone resorption
109
What are causes of muscle plasticity in jaw function?
Tooth extractions
Surgical interventions
Orthodontic interventions
110
How does Poliomyelitis affect motor units?
Kills motoneurons in Anterior Ventral Spinal Cord
111
How does Multiple Sclerosis affect motor units?
Demyelination of motor axons
112
How does Myasthenia Gravis affect motor units?
Blockage of ACh receptors
113
How does Muscular Dystrophy affect motor units?
Contraction of muscle fibres inhibited
114
What is an example of reflex inhibition of jaw-closer muscles on a periodontal reflex?
Muscle Inhibition on rapid increase in load force: eg biting down on a stone in a sandwich
115
What are 2 examples of Jaw Closing/Jerk reflexes?
Maintaining rest position whilst running
Biting on a nut - adjusting for decreased resistance
116
Dentinal Hypersensitivity is mostly caused by what sort of fluid movement?
Outward: Air, Drilling, Probing, Osmotic Stimuli (Sucrose: draws water out)
117
What are the 9 components of Neuromatrix pain theory?
```
Afferent Input
Medullary Descending Inhibition
Pain Perception
Pain Behaviour
Psychosocial/Health Status Factors
Attention
CNS Plasticity
Pathologic Input
Endocrine, Immune and Autonomic System Activity
```
118
T/F: If the Gate is Closed in Gates Control Theory, there is pain
False, if gate is closed there is no pain
119
In Gates Control Theory, stimulus from small fibres results in what?
Opens the Gate
120
In Gates Control Theory, stimulus from large fibres results in what?
Closing the Gate: no pain (example: massaging the face during LA to stimulate large fibres)
121
A lesion within the ventral trigeminothalamic tract after the midline will result in what sort of sensation loss?
Contralateral loss of pain and temperature from the head and face
122
A lesion within the spinotrigeminal tract will result in what sort of sensation loss?
Ipsilateral loss of pain and temperature from the head and face
123
What is the tract name for the trigeminal second order axons after they have crossed the midline?
Ventral Trigeminothalamic Tract (Trigeminal Lemniscus)
124
Trigeminal nerve innervates the orofacial area. What structure is the relay station for the nerve fibres carrying pain sensations from the maxillary molar tooth?
Spinal Nucleus of CN V
125
Subnucleus Oralis, Interpolaris, Caudalis can be found where?
Within the spinal nucleus of CN V
126
What can Wide Dynamic Range (WDR) 2nd order neurons respond to?
Respond to noxious/non-noxious stimuli including Light Touch, Temperature, Proprioception
127
Where do the neurons crossover in the Spinothalamic Tract?
2nd order neuron at the spinal cord associated with the initial sensory input
128
How can Central Sensitisation be avoided when doing a 3rd molar extraction?
Use of a long acting analgesic and anti-inflammatory post operatively
129
What 2 things does the release Substance P result in?
1. Inflammation Release (mast cell degranulation, histamine, activation of nociceptors)
2. Plasma Extravasation
130
In a hot pulp, what does a oedema result in?
Additional release of bradykinin and activation of nociceptors
131
What is the role of Calcitonin Gene Related Peptide (CGRP) in a hot pulp?
Results in dilation of peripheral blood vessels and creation of oedema
132
What 4 things can activate nociceptors during injury?
Damaged Cells: K+
Damaged Vessels: Bradykinin
Damaged Endothelial Cells: Serotonin + Platelets
Mast Cells: Histamine
133
What 2 chemical can sensitise noiciceptors?
Damaged Cells: Prostaglandins
| Primary Afferent: Substance P
134
What sites of mechanical stimulation can trigger the gag reflex?
Faucial Pillar
Base of the Tongue
Soft Palate
Posterior Pharyngeal Wall
135
What is the order of relief of pain?
1. Relief to burning pain (C Fibres)
2. Temperature and Prickling Pain (A-delta Fibres)
3. Touch / Pressure sensation (Large A Fibres)
136
Sensitivity of nerve fibres to LA depends on what 3 things?
1. Size of Nerve Fibre: smaller fibres are blocked first
2. State of Myelination: myelinated fibres are blocked first
3. Rate of Firing: rapidly firing neurons are blocked first as they have more affinity for LA
137
What fibres are stimulated with FIRST pain?
A Beta - transmits impulses quickly
138
What sort of fibres are A-Beta Fibres?
Large Myelinated Fibres
139
Patient feels a throbbing type of poorly localised pain after an injury. What fibres are involved with the pain?
C Fibres
140
Unmelinated C Fibres are involved with what sort of pain?
Slow Pain
141
What is Allodynia?
Pain from a stimulus that doesn't usually invoke pain. eg Trigeminal Neuralgia
142
What fibres are involved with fast pain?
A-Delta Fibres
143
What are the characteristics of fast pain?
Sharp Pain
Well Localised
Short Duration
Afferent signals from Thermal + Mechanical Nociceptors
