Brainscape's Knowledge GenomeTM

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


See full index

Physiology > Oral Physiology (7/21/15) > Flashcards

Oral Physiology (7/21/15) Flashcards

1
Q

Describe the Genioglossus muscle…

A

Very fast, high proportion of fast twitch fibers.

- An intrinsic tongue muscle that forms the majority of the body of the tongue.

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

What are the Jaw opener muscles?

A

Digastric

  • Predominalty fast
  • Two heads in series - functional implications

Lateral Pterygoid

  • Actually a protractors (Protraction accompanies opening)
  • Dysfucntion of the Superior head is associated with Ant. displacement of TM disc in TM dysfunction.

Geniohyoid

Mylohyoid

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

What are the Jaw closer muscles?

A

Masseter

  • Two parts: deep and superficial, slow fibers predominate in both parts.
  • Ant. to post. Gradient
  • Bruxing can lead to hypertrophy which may up regulate slow myosin which can cause slower, less powerful contractions (chewing problems)

Temporalis

  • Faster than Masseter (more fast-type myosin)
  • Tendency for compartmentalization (slower anteriorly, faster posteriorly.
  • Usually more powerful in females.
  • Due to Compartmentalization, injury can have differential effects.

Medial Pterygoid

  • Slow myosin predominates
  • same Ant.-to-Post. gradient in myosin expression.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the generally true of all jaw closers?

A

Have greater amounts of sow myosin in deep vs superficial and in anterior vs posterior!

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

What is Kinesthesia?

A

Refers to the sense of movement and position.

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

T or F, Masticatory muscles are under exquisite control.

A

True, this protects the teeth and soft tissues from damage and insures safe/effective chewing.

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

Why is Kinesthesia Important?

A

Because the same set of jaw closing muscles can drive very different motor functions, involving a broad range of precision and force generation (Lion killing gazelle vs carrying it’s cub)

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

What are the main components of a Muscle spindle?

A
  1. External Capsule
  2. Muscle fibers
  3. Efferent Nerve Fibers (10 or more per spindle)
  4. Sensory Fibers
  5. Lymph
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the 3 types of muscle fibers?

A
  1. Nuclear bag intrafusal fibers (2-3/spindle) = sense onset of stretch
  2. Nuclear chain intrafusal fibers (4-6/spindle) = sense sustained stretch
  3. Extrafusal fibers = most fibers in muscle which do the work associated with muscle contractions.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 2 types of Efferent Nerve fibers?

A
  1. Gamma fusimotor fibers (most common)

2. Beta fusimotor fibers (Rare, 1/3 of all spindles)

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

What are the 2 types of sensory nerve endings?

A

1A afferent fibers = “Primary endings”

2 Afferent fibers = “Secondary endings”

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

What is the role of Gamma fusimotor fibers?

A

To Maintain high level of spindle sensitivity in shortened muscles.

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

What happens to Afferent (sensory) activity as muscle shortens?

A

It decreases, this is an important component of kinesthesia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are Muscle spindles?

A

Muscle spindles are receptors that can sense the level of “Stretch or strain” placed on muscle or length of the muscle, and convey that info to the CNS.

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

Can activation of Gamma or Beta (Efferent) fusimotor fibers cause contraction of muscle?

A

No b/c they go to muscle spindles and they are not string enough to contract muscle. Alpha fusimotor fibers cause muscle contraction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does your body prevent injury during rapid/unexpected muscle stretch?

A

Well, Both Bag and chain intrafusal fibers (spindles) respond to rapid stretch, sending a signal to the spinal cord which activates a contraction reflex on extrafusal muscle fibers via the alpha (efferent) motor fiber.

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

What would happen if the internal adjustments in the spindle would not occur after the muscle shortens?

A

Then the muscle would function over range of short lengths where spindles would remain reactive.
However, instead, Gamma neurons cause poor regions of intrafusal fibers to shorten —> stretches equatorial regions —> restoration of sensitivity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are Golgi Tendon Organs (GTO)?

A

Receptors located in the junction between ends of muscle fibers and tendon.

  • Located in tendon and positioned in series with muscle fibers.
  • Generated signals that are proportional to the amount of force generated by extrafusal muscle fibers.
  • have “Tendon Organ Afferent fibers” running from them.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the Mode of action for GTO’s?

A
  1. AP in GTO
  2. Tension in GTO
  3. Stretch applied to GTO
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are free nerve endings in the joints and what are their functions?

A

Free nerve endings are those without specialized endings (Ex. Pacinian corpuscles are specialized) and are often nociceptive (activated by painful stimuli) while others are activated by mechanical stimuli and therefore can provide info concerning joint position.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is Electromyography (EMG)?

A

the recording and analysis of muscle activation by recording non-invasive information about patterns of muscle activators.

*Basis is AP’s along the sarcolemma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does EMG reflect about masticatory events?

A

Very precise timing in events such as chewing, swallowing and speaking.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How can EMG be utilized to address a clinically relevant question: “Is jaw closing muscle function compromised in patients with a unilateral marginal mandiblectomy?”

A
  1. Measure EMG activity of masseter and temporals muscles during different types of chewing.
  2. Compare those results to those from normal individuals.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Does EMG reflect the actual forces generated across the joint?

A

No. Nor should it, since some antagonistic muscles produce a net force of 0 across joint by balancing each other out.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is Mastication?

A

An Extremely complex interaction between motor and sensory components involving specialized masticatory muscles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Control of mastication is provided by _______.

A

The CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the mandibular movements during mastication?

A
  1. Highly rhythmic and specific (Depending on food consistency)
  2. Lowering (jaw opening) = digastric and lateral pterygoid
  3. Elevating (jaw closing) = masseter, temporalis and medial pterygoid.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the difference between masticatory muscles in carnivores vs herbivores?

A 
Carnivours = larger temporalis
Herbivores = larger masseter
29
Q

What are the 4 phases of the chewing cycle?

A

slow opening
fast opening
fast closing
slow closing

30
Q

What are the 3 masticatory phases?

A
  1. Preparatory = tongue, lips, buccinator (highly variable depending on food) * fairly variable
  2. Reduction = food breakdown *Very rhythmic and regular
  3. Pre-swallowing = food bolus formation *Very regular
31
Q

What Structures are involved in Central control of Mastication?

A

The primary sites of control are the Brain stem and the Cerebral Cortex, both afferent and efferent tracts of fibers.

32
Q

What are the 2 Sensory nuclei of Mastication?

A

Trigeminal Sensory Nucleus = cells that innervated face and oral cavity. *project to cerebellar as well as cerebral cortex.

Trigeminal Mesencephalic Nucleus = cell bodies of spindle afferents from jaw closers, mechanoreceptors in periodontal ligaments, gingiva and palate.

33
Q

What are the 3 Motor Nuclei of mastication?

A
  1. Trigeminal motor nucleus = alpha and gamma motor neurons of jaw muscles with high degree of topographic organization.
  2. Hypoglossal motor nucleus = motor neurons of tongue muscles.
  3. Facial motor nucleus = motor neurons of facial muscles, also topographically organized.
34
Q

What is the Role of the Brainstem in Masticatory control?

A

Can function autonomously in the control of mastication = no input from higher centers required. However, normally does receive such input. *probably contains a “pattern generator” or “Neural oscillator” fro mastication.

*Fun fact: motor, sensory and premotor cortex are active during voluntary clenching, but the premotor cortex is not active during gum chewing.

35
Q

Cortical activation associated with chewing are _____.

A

Bilateral

36
Q

Tell me about the Jaw closing reflex….

A
  • Via afferent fibers from muscle spindles
  • Cell bodies in mesencephalic (sensory) nucleus synapse on alpha motor neurons in trigeminal motor nucleus.
  • Monosynaptic = very fast with virtually no modulation from higher centers.
37
Q

Tell me about the Jaw opening Reflex…

A

So basically, a stimulus in the oral cavity excites afferents that terminate in spinal trigeminal tract nucleus cells which synapse on interneurons, which, in turn, synapse on alpha motor neurons in the trigeminal motor nucleus which innervate jaw openers.

*Post synaptic reflex = highly modulated for specific stimulus

38
Q

What is the role of higher centers in Mastication?

A

Modulation of mastication can be entirely voluntary (But is usually not) including jaw-closing (monosynaptic = very little modulation) and jaw opening reflexes.

39
Q

What is the role of afferents in Mastication?

A

Modulation of mastication regarding food consistency.

  • Variable receptors involved with several types of input (hard vs soft food)
  • Input to brain stem and higher centers.
40
Q

What is swallowing? Voluntary, Involuntary?

A

A very complex task that is a reflex AFTER initiation (normally unconscious) *Occurs approx 1,000 per day.

41
Q

What components are involved with swallowing?

A

Large area of brain stem
Six cranial nerves
Receptors
Muscles

42
Q

What are the 4 phases of Swallowing?

A
  1. Preparatory Phase = formation of food bolus. (Same as pre swallowing in mastication phases)
  2. Oral Phase = movement of bolus from oral cavity to pharynx 0.5sec.
  3. Pharyngeal Phase = movement of bolus from oropharynx to esophagus 0.7sec.
  4. Esophageal phase = movement of food along entire esophagus (3 sec for liquids, 9 sec for solids)
43
Q

What is the Glossopalatal sphincter?

A

When, (During the Preparatory phase) the posterior portion of the tongue rises to contact the soft palate which pushes down and forms a temporary sphincter to prevent bolus entering pharynx prematurely.

44
Q

What are the 2 INITAL actions that occur IN SEQUENCE during the oral phase?

A
  1. Lips close, upper and lower incisors move close together = forms oral seal.
  2. Ant. 2/3rds of tongue moves up and pushes bolus towards the pharynx.
45
Q

What are the 3 events that occur SIMULTANEOUSLY during the Oral phase?

A

After INITAL 2 actions: This all happens at once:

  • base of tongue moves downward and forward epic expands the hypo pharynx and opens a chute to the pharynx
  • Palate move up = opens the glossopalatal sphincter
  • Palate contacts post. pharyngeal wall and the side walls of the nasopharynx are opposed = this prevents bolus from entering the nasal cavity.
46
Q

What muscles are involved in the Preparatory and oral phases of swallowing?

A

Mandibular (Masseter, medial pterygoid, temporalis

Facial (labial and buccinator)

47
Q

What is the facultative group of muscles?

A

The ones that are currently actively functioning during the Preparatory and oral phases of swallowing.

48
Q

What 4 actions occur during the Pharyngeal phase of swallowing?

A
  1. Piston-like movement of tongue propels bolus through oropharynx and into hypopharynx.
  2. Pharyngeal constrictors contract several times = move the bolus through the pharynx.
  3. Upper esophageal sphincter ones = allows the bolus to enter the esophagus.
  4. Epiglottis movement from upright to horizontal closes the opening to the larynx. *epiglottis not absolutely needed.
49
Q

What muscles are involved in the Pharyngeal phase of swallowing?

A

Collectively referred to as “Obligate group” of muscles.

  • Mylohyoid (leading complex)
  • geniohyoid (Leading complex)
  • Thyrohyoid
  • Thyroarytenoid
  • middle constrictor
  • cricothryroid
  • inferior constrictor
  • Much more consistent than first 2 phases of swallowing
50
Q

When does the Upper esophageal sphincter relax (open)?

A

When tongue and upper pharynx contract, so it its open before the pressure wave passes through the pharynx. *Closes after food enters esophagus.

51
Q

When does the Lower esophageal sphincter relax (open)?

A

About 3 secs before peristaltic wave hits it and remains open until last swallows are complete.

52
Q

What are the 4 mechanisms that prevents aspiration of food during the pharyngeal phase?

A
  1. Respiration is inhibited
  2. Larynx and iper esophageal sphincter elevate
  3. Intrinsic muscles of glottis move vocal cords towards each other.
  4. Bolus moves through sinuses in pharynx.
53
Q

What type of control is swallowing under?

A

First two phases are voluntary yet subconscious

Last two are involuntary

54
Q

What is “The Swallowing Center”? (3 components here)

A

The Brainstem: 3 components

  1. Sensory Nuclei
    - Nucleus tractus solitarius (NTS)
    - Trigeminal sensory nucleus
  2. Motor Nuclei
    - nucleus ambiguous
    - facial, trigeminal and hypoglossal nuclei
  3. Interneuronal network***
55
Q

What does the Interneuronal network of the brainstem do?

A

Mediates interactions between motor and sensory nuclei. It is not a specific structure, rather spread out in ventral and dorsal regions of the Medulla.

  • Dorsal interneurons = initiation and programming or timing of swallowing.
  • Ventral interneurons = distribute the excitation tot he swallowing motor nuclei.
56
Q

What is the pathway of afferent information during swallowing?

A
  1. originates in the pharynx, larynx and esophagus
  2. sent to NTS
  3. Results in modification of swallow, depending of food consistency.
    * Note: activation of afferent fibers can also lead to inhibition of some motoneurons (Esophageal motoneurons are inhibited during the oral and pharyngeal phase!)
57
Q

Describe Infantile swallowing?

A

Programing of Obligate muscle timing that begins in utero. Very different from facultative muscles that have different patterns of activation before and aft tooth eruption.

58
Q

_______ do not have a prominent role in swallowing before eruption.

A

Jaw closing muscles

59
Q

Before tooth eruption ____________ make up for lack of jaw closer muscle action in swallowing.

A

orbicularis oris, buccinator muscles and tongue thrust

60
Q

What is the difference between Infant and adult suckling?

A 
Infant = both jaw opening and closing muscles have important roles.
adult = driven by inspiratory muscles.
61
Q

What are the 2 stimuli for Emesis (Vomiting)?

A

Physiological stimuli = pain, injury, irritation of gut….

Disease related stimuli = psychological stress, stenosis of pyloric valve…..

62
Q

What are the Phases of vomiting?

A
  1. Pre-ejection = relation of proximal portion of stomach, salvation, licking (Minutes - days)
  2. Ejection = Retching and expulsion phases
    - Retching = glottis is closed and inspiratory muscles contract causing a decrease in intra thoracic pressure and increase in intra-abdominal pressure. 1-2 seconds between each retch
    - Expulsion = Antrum of stomach relaxes, rectus abdomens and external obliques contract, upper esophageal sphincter relaxes. Intra-Thoracic and intra abdominal pressure rises to 100 mm Hg compared to 10 mm Hg
  3. Post expulsion = can now terminate or take another retching ride…
63
Q

What coordinates the vomiting act?

A

A group of nuclei in the medulla.

* Direct stimulation of the NTS in animals causes vomiting.

64
Q

What are the Characteristics of bruxism?

A
  • Forceful tooth clenching and grinding during sleep.
  • sometimes rhythmic chewing and sustained contraction
  • daytime tooth clenching is similar to bruxism in mechanics.
65
Q

What causes bruxism?

A

Associated with certain sleep phases (may have CNS origin) appears to correlate to stress.

66
Q

What are the consequences of bruxism?

A
  • tooth wear
  • pain
  • possible muscle damage
  • headaches
67
Q

Treatment for bruxism?

A
  • Reduce stress

- bite appliance therapy

68
Q

Tell me about Temporomandibular disorders….

A

Not well understood, but 2 major issues: Pain and chewing efficiency.

  • more common in women than men.
  • women report more pain
  • men report more impairment of chewing and jaw opening.
  • TMD tends to increase with age.

Physiology (9 decks)

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