Quiz 2

Question 1

Masseter

Answer 1

Superficial to mandible
elevates mandible
some protrusion
Creates muscular sling with medial pterygoid

Question 2

Temporalis

Answer 2

3 Portions:
Anterior - elevates mandible
Middle - elevates  and retrudes (opposite of protrude) mandible
Posterior - retrudes mandible
Runs under zygomatic arch

Question 3

Medial Pterygoid

Answer 3

Creates muscular sling with masseter, sits deep to mandible
elevates and protrudes mandible
Unilateral contraction: mediotrusive movement (lateral and to opposite side)

Question 4

Lateral Pterygoid

Answer 4

Inferior and Superior Body/Belly
Primary protruder of mandible
Contracts upon CLOSING, not opening

Question 5

Inferior Lateral Pterygoid

Answer 5

Bilateral Contraction: protrusion

Unilateral Contraction: lateral movement to opposite side

Question 6

Digastric

Answer 6

One muscle with a Posterior and Anterior belly separated by a tendon (Intermediate Tendon)
Both sit below mandible and attach to hyoid bone
Not considered a true muscle of mastication

Question 7

Digastric Muscle Function - Fixed Hyoid

Answer 7

Mandible is depressed and brought backwards.

Fixed Hyoid happens via supra & infrahyoid muscles

Question 8

Digastric Muscle Function - Fixed Mandible

Answer 8

Fixed mandible via digastric, infra and suprahyoid muscles which raises the hyoid bone = SWALLOWING

Question 9

Digastric Muscle Function - Fixed Mandible

Answer 9

Fixed mandible via digastric, infra and suprahyoid muscles which raises the hyoid bone = SWALLOWING

Question 10

Suprahyoid Muscles

Answer 10

muscles that span from mandible to hyoid

Question 11

Infrahyoid Muscles

Answer 11

Muscles that span from hyoid to clavicle and sternum

Question 12

Exteroceptors

Answer 12

provide info from exterior tissues of the body to inform CNS of conditions in the environment of that receptor

Question 13

Nociceptors

Answer 13

Pain and discomfort

Question 14

Proprioceptors

Answer 14

Position and movement of mandible and associated oral structures

Question 15

Interoceptors

Answer 15

Internal organs and processes like blood flow, digestion, breathing

Question 16

Primary / First Order Neurons

Answer 16

Carry input into dorsal horn. Synapse with second-order / secondary neurons or motor neurons

Question 17

Secondary / Second Order Neurons

Answer 17

Carry information to different levels of the spinal cord

Question 18

Trace Trigeminal Nerve Input

Answer 18

1. Cell bodies of trigeminal n located in the gasserian ganglion (GG)
2. Primary afferent neuron enters brainstem to synapse with the second-order neuron in the trigeminal spinal tract nucleus (STN of V).
3. Second-order neuron to the thalamus for interpretation
4. Thalamus sends information to cortex

Question 19

Spinal Tract Nucleus of Trigeminal Nerve

Answer 19

Located in the brainstem
Broken into 3 parts
1. Subnucleus Oralis (sno) oral pain mechanisms
2. subnucleus interpolaris (sni)
3. subnucleus caudalis (snc) trigeminal nociceptive mechanisms
tooth pulp to all 3

Question 20

Trigeminal Brainstem

Answer 20

1. Spinal Tract Nucleus (sno, sni, snc)
2. Main sensory nucleus of V (SN of V)
3. Motor nucleus of V (MN of V)

Question 21

Reticular Formation

Answer 21

monitors impulses that enter the brain via enhancing impulses or inhibiting impulses.

Question 22

Thalamus

Answer 22

drives cortex to activity and enables communication between cortex and rest of the CNS. Without thalamus the cortex is useless!!
“keyboard” that controls functions and directs signals

Question 23

Hypothalamus

Answer 23

Thirst
Hunger
Body Temperature

Question 24

Limbic Structures

Answer 24

emotional and behavioral activities

Question 25

Cortex

Answer 25

thinking process muscle skills special senses

Question 26

Central Pattern Generator - CPG

Answer 26

pool of neurons that control rhythmic muscle activities such as breathing, walking, chewing. Precise timing of activity between antagonistic muscles for special functions

Question 27

Muscle Engrams

Answer 27

Learned & repeated pattern of chewing that minimizes damage to oral structures.

Question 28

Superior Lateral Pterygoid

Answer 28

remains inactive during opening and active during closing | Especially active during power stroke and when teeth are held together

Question 29

Mastication

Answer 29

``` An efficient chewing pattern that minimizes damage to structure Learned & Repeated (engram) Automatic and practically involuntary 2 phases -opening -closing (crushing & grinding) ```

Question 30

Opening phase

Answer 30

Mandible is depressed and shifts 3-4 mm laterally

Question 31

Closing Phase - Crushing

Answer 31

Majority of closing phase At maximum opening begin to shift medial Buccal cusps of mandibular teeth directly under buccal cusps of maxillary teeth which helps trap food between them.

Question 32

Closing Phase - Grinding

Answer 32

Last bit of closing phase Mandible guided by occlusal surfaces of teeth to IP Cuspal inclines pass across each other= shearing & grinding of Bolus

Question 33

Lateral Movements of Mandible

Answer 33

``` Depend on stage of Mastication -Early= more lateral movement -Late= less lateral movement Depends on food consistency -Hard=more lateral movement -Soft=less lateral movement ```

Question 34

Forces of Mastication

Answer 34

Female average: ~80 lbs Male average: ~120 lbs Greatest: 975 lbs Varies by teeth (first molars > incisors) Varies by prosthetics (dentures 25% force) Varies by pain (tooth/muscle pain reduce force)

Question 35

Swallowing - Deglutition

Answer 35

Coordinated muscular contractions that move bolus to stomach Voluntary, involuntary, and reflex muscular activity Must have a stabilized mandible to allow movement of hyoid - different in adults and infants

Question 36

Duration & Force of Swallowing

Answer 36

Takes 3x as long as tooth contact during mastication | 7.8 lbs more than mastication

Question 37

Somatic Swallow

Answer 37

adult uses teeth for mandibular stability

Question 38

Visceral Swallow

Answer 38

Infant uses tongue forward and between dental arches to stabilize mandible to allow hyoid movement