EX1; Oral Musculature Flashcards Preview

AU14 Physiology > EX1; Oral Musculature > Flashcards

Flashcards in EX1; Oral Musculature Deck (73)
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1
Q

This muscle is very fast, has a high proportion of fast-twitch fibers; forms the majority of the body of the tongue

A

genioglossus

2
Q

This muscle is predominantly fast and has two heads in series with functional implications; jaw opener

A

diagastric

3
Q

This is a protractor muscle accompanying opening; dysfunction of superior head is associated with anterior displacement of TM disc

A

lateral pterygoid

4
Q

These are strap like muscles involved in jaw opening

A

geniohyoid

mylohyoid

5
Q

This jaw closing muscle has two parts; deep and superficial and slow fibers predominate on both parts

A

masseter

6
Q

What are the myosin isoforms of the masseter

A

adult slow

embryonic, neonatal, alpha cardiac (latter serves in rhythmic contractions

7
Q

What is the gradient (slow-fast myosin gradient) of the masseter

A

anterior to posterior

8
Q

This may increase in level of slow myosin in which may cause slower, less powerful contractions that could affect chewing, speech, etc.

A

bruxing

9
Q

This jaw closer contains more fast-type than myosin than masseter; with slow anteriorly and fast posteriorly compartmentalization

A

temporalis

10
Q

Due to the compartmentalization in the temporalis, what could this mean for an injury/lesion

A

it may have differential effects

11
Q

This jaw closer has predominately slow myosin and an anterior to posterior gradient

A

medial pterygoid

12
Q

What is the general pattern involving the relative amount of slow myosin among jaw closers

A

greater amounts in deep and in anterior
less in superficial and posterior
(slow deep and anterior)
(fast superficial and posterior)

13
Q

This is the sense of movement and position

A

kinesthesia

14
Q

True or False

Masticatory muscles are under exquisite control

A

True; protects teeth and soft tissues from damage and ensures effective chewing

15
Q

What does the rich sensory information originating from within the masticatory muscles provide

A

feedback to the CNS which provides the neural drive for contraction

16
Q

True or False

There is continuously on-going sensory information from all muscles; of which normally not aware of it

A

True

17
Q

What is the dimensions of a muscle spindle

A

1-3 mm in length

200µm in diameter

18
Q

What are the two intrafusal fibers that make up muscle fibers

A

nuclear bad intrafusal fibers (2-3/spindle)

nuclear chain intrafusal fibers (4-6/spindle)

19
Q

Most fibers in a muscle are what, which do the work (force, limb movement) associated with muscle contractions

A

extrafusal

20
Q

What are the two types of efferent nerve fibers (10 or more/spindle)

A

gamma; fusimotor fibers (most common)

beta; fusimotor fibers (relatively rare, 1/3 of all spindles)

21
Q

What are the two types of sensory nerve fibers

A

Ia afferent fibers; primary endings

II afferent fibers; secondary endings

22
Q

True or False

There is lymph in the muscle spindle

A

True

23
Q

A muscle spindle’s main mode of action is what kind of sensory

A

a length sensor; apply stretch to spindle; tension

24
Q

This type of motor neuron maintains a high level of spindle sensitivity in shortened muscles

A

gamma

25
Q

Afferent activity decreases when

A

as a muscle shortens; an important component of kinesthesia

26
Q

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

A

The muscle would function over a range of short lengths where spindles would remain inactive

27
Q

gamma motor neurons cause polar regions of intrafusal fibers to shorten, causing what

A

stretching equatorial regions restoring sensitivity

28
Q

What is the correlation between the distribution of muscle spindles and of slow type muscle fibers

A

they mirror that of one another

29
Q

These are receptors in skeletal muscles which are located in the junction between the ends of the muscle fibers and the tendon to which a muscle is attached

A

golgi tendon bodies

30
Q

Where is the location of golgi tendon bodies

A

located in the tendon and positioned in-series with muscle fibers

31
Q

What type of signals do the golgi tendon bodies generate

A

signals that are proportional to the amount of force generated by extrafusal muscle fibers (to the CNS)

32
Q

What information is being picked up by the golgi tendon organs at the upper/middle/lower traces

A

upper; action potentials of GTO
middle; tension in GTO
lower; stretch applied to GTO

33
Q

Many of the free nerve endings (those without specialized endings such as pacinian corpuscles) are nociceptive, which means what

A

they are activated by painful stimuli

others are activated by mechanical stimuli and such can provide information concerning joint position to CNS

34
Q

This is a recording and analysis of muscle activations; action potentials along sarcolemma of muscle fibers (extrafusal)

A

EMG; electromyography

35
Q

True or False

An EMG is an invasive gathering of information about patterns of muscle activations

A

False; it is non-invasive

36
Q

EMGs do not necessarily reflect what

A

forces generated across a joint; solely responds to electrical information

37
Q

What type of patterns can be revealed by an EMG

A

very interesting ones; like very precise timing of masticatory events relative to each other

38
Q

True or False
an EMG can be used clinically to compare someone with normal masticatory functions with someone who has had a mandiblectomy

A

True

39
Q

This is an extremely complex interaction between motor and sensory components of highly specialized muscles which is highly rhythmic and specific depending upon food consistency

A

mastication

40
Q

Mastication has rich supplies of afferent information from where

A

muscles, oral cavity, and facial regions

41
Q

Control and coordination is provided by what

A

the CNS

42
Q

What two muscles are involved with lowering the mandible (opening)

A

digastric and lateral pterygoid

43
Q

What three muscles are involved with elevating the mandible (closing

A

masseter, temporalis, and medial pterygoid

44
Q

This type of animal has a large temporal is and jaw closers express masticatory myosin

A

carnivores

45
Q

This type of animal has a large masseter; jaw closers express alpha cardiac myosin, no masticatory myosin

A

herbivores

46
Q

This type of animal has relatively unspecalized mandibular features and a variable diet

A

omnivores

47
Q

What are the four phases of the chewing cycle

A

slow opening
fast opening
fast closing
slow closing

48
Q

What are the three masticatory phases

A

preparatory
reduction
pre-swallowing

49
Q

This masticatory phase is for transport; tongue, lips, buccinator; highly variable depending on food and consistency

A

preparory

50
Q

This masticatory phase is food breakdown

A

reduction

51
Q

This masticatory phase is food bolus formation

A

pre-swallowing

52
Q

There is little EMG activity during which masticatory stage

A

preparatory

53
Q

When is the altering EMG activities during mastication

A

in openers and closers

54
Q

Which phases of mastication are regular?

A
reduction (regular and rhythmic)
pre swallowing (regular)
55
Q

Each masticatory phase is dependent upon what

A

food consistency

56
Q

What are the two primary control sites of the brain

A

brain stem and cerebral cortex

57
Q

What three structures do the brain and cerebral cortex involve in the control of mastication

A

nuclei
afferent tracts of fibers
efferent tracts of fibers

58
Q

What are the two sensory nuclei associated with control of mastication

A

trigeminal sensory

trigeminal mesencephalic

59
Q

This sensory nucleus cells innervate the face and oral cavity; project to cerebellar, as well as cerebral cortex

A

trigeminal sensory

60
Q

This sensory nucleus cell bodes of spindle afferents from jaw closers, mechanoreceptors in periodontal ligaments, gingiva, and palate

A

trigeminal mesencephalic

61
Q

What are the three motor nuclei associated with control of mastication

A

trigeminal motor
hypoglossal motor
facial motor

62
Q

This motor nucleus contains neurons of the facial muscles; topographically organized

A

facial motor nucleus

63
Q

This motor nucleus contains motor neurons of tongue muscles

A

hypoglossal motor nucleus

64
Q

This motor nucleus contains ɑ and Ɣ motor neurons of jaw muscles; high degree of topographic organization

A

trigeminal motor nucleus

65
Q

This can function autonomously in the control of mastication, no input from higher centers required however normally does receive such input

A

brain stem

66
Q

What does the brainstem “probably” contain

A

a pattern generator or neural oscillator for mastication

67
Q

This reflex is monosynaptic; very fast with virtually no modulation from higher centers

A

jaw closing reflex

68
Q

The cell bodies in the mesencephatic (sensory) nucleus synapses on what

A

the ɑ motor neurons in trigeminal motor nucleus

69
Q

The jaw closing reflex uses these fibers from muscle spindles

A

afferent fibers

70
Q

In the jaw opening reflex the stimulus in the oral cavity excites afferents that terminate the spinal trigeminal tract nucleus cells which synapse on interneurons which in turn synapse where

A

the ɑ motor neurons in trigeminal motor nucleus which innervate jaw openers

71
Q

This is polysynaptic reflex; highly modulated for specific stimulus

A

jaw opening reflex

72
Q

True or False

Mastication can be entirely voluntary; including that of jaw-closing and jaw-opening reflexes

A

True; but it is usually not

73
Q

True or False
There are variable afferent receptors involved with the several types of input of food consistency; like hard vs soft, chewy vs cripsy

A

True