EX1; Oral Musculature Flashcards Preview

AU14 Physiology > EX1; Oral Musculature > Flashcards

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

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

genioglossus

2

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

diagastric

3

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

lateral pterygoid

4

These are strap like muscles involved in jaw opening

geniohyoid
mylohyoid

5

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

masseter

6

What are the myosin isoforms of the masseter

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

7

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

anterior to posterior

8

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

bruxing

9

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

temporalis

10

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

it may have differential effects

11

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

medial pterygoid

12

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

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

13

This is the sense of movement and position

kinesthesia

14

True or False
Masticatory muscles are under exquisite control

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

15

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

feedback to the CNS which provides the neural drive for contraction

16

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

True

17

What is the dimensions of a muscle spindle

1-3 mm in length
200µm in diameter

18

What are the two intrafusal fibers that make up muscle fibers

nuclear bad intrafusal fibers (2-3/spindle)
nuclear chain intrafusal fibers (4-6/spindle)

19

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

extrafusal

20

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

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

21

What are the two types of sensory nerve fibers

Ia afferent fibers; primary endings
II afferent fibers; secondary endings

22

True or False
There is lymph in the muscle spindle

True

23

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

a length sensor; apply stretch to spindle; tension

24

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

gamma

25

Afferent activity decreases when

as a muscle shortens; an important component of kinesthesia

26

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

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

27

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

stretching equatorial regions restoring sensitivity

28

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

they mirror that of one another

29

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

golgi tendon bodies

30

Where is the location of golgi tendon bodies

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

31

What type of signals do the golgi tendon bodies generate

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

32

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

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

33

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

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

34

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

EMG; electromyography

35

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

False; it is non-invasive

36

EMGs do not necessarily reflect what

forces generated across a joint; solely responds to electrical information

37

What type of patterns can be revealed by an EMG

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

38

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

True

39

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

mastication

40

Mastication has rich supplies of afferent information from where

muscles, oral cavity, and facial regions

41

Control and coordination is provided by what

the CNS

42

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

digastric and lateral pterygoid

43

What three muscles are involved with elevating the mandible (closing

masseter, temporalis, and medial pterygoid

44

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

carnivores

45

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

herbivores

46

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

omnivores

47

What are the four phases of the chewing cycle

slow opening
fast opening
fast closing
slow closing

48

What are the three masticatory phases

preparatory
reduction
pre-swallowing

49

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

preparory

50

This masticatory phase is food breakdown

reduction

51

This masticatory phase is food bolus formation

pre-swallowing

52

There is little EMG activity during which masticatory stage

preparatory

53

When is the altering EMG activities during mastication

in openers and closers

54

Which phases of mastication are regular?

reduction (regular and rhythmic)
pre swallowing (regular)

55

Each masticatory phase is dependent upon what

food consistency

56

What are the two primary control sites of the brain

brain stem and cerebral cortex

57

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

nuclei
afferent tracts of fibers
efferent tracts of fibers

58

What are the two sensory nuclei associated with control of mastication

trigeminal sensory
trigeminal mesencephalic

59

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

trigeminal sensory

60

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

trigeminal mesencephalic

61

What are the three motor nuclei associated with control of mastication

trigeminal motor
hypoglossal motor
facial motor

62

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

facial motor nucleus

63

This motor nucleus contains motor neurons of tongue muscles

hypoglossal motor nucleus

64

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

trigeminal motor nucleus

65

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

brain stem

66

What does the brainstem "probably" contain

a pattern generator or neural oscillator for mastication

67

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

jaw closing reflex

68

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

the ɑ motor neurons in trigeminal motor nucleus

69

The jaw closing reflex uses these fibers from muscle spindles

afferent fibers

70

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

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

71

This is polysynaptic reflex; highly modulated for specific stimulus

jaw opening reflex

72

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

True; but it is usually not

73

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

True