Muscles of mastication + oral cavity M7 Flashcards
1
Q
what are the four muscles of mastication?
A
- temporalis
- masseter
- medial pterygoid
- lateral pterygoid
2
Q
temporalis - origin
A
temporal fossa
3
Q
temporalis - insertion
A
coronoid process and ramus of mandible
4
Q
temporalis - actions
A
elevates and retracts mandible
5
Q
masseter - origin
A
zygomatic arch
6
Q
masseter - insertion
A
angle and lateral surface of ramus and mandible
7
Q
masseter - actions
A
elevates (and slightly protrudes) mandible
8
Q
medial pterygoid - origin
A
- superficial head = pyramidal process of palatine bone and tuberosity of maxilla
- deep head - medial surface of lateral pterygoid plate of sphenoid bone
9
Q
medial pterygoid - insertion
A
medial surface of ramus of mandible
10
Q
medial pterygoid - actions
A
- bilaterally - elevates and protrudes mandible
- unilaterally ( with lateral pterygoid) - laterally deviates mandible to contralateral side
11
Q
lateral pterygoid - origin
A
- upper head - greater wing of sphenoid bone
- lower head - lateral surface of lateral pterygoid plate of sphenoid bone
12
Q
lateral pterygoid - insertion
A
neck of condylar process of mandible, TMJ capsule and articular disc (that divides cavity into 2)
13
Q
lateral pterygoid - actions
A
- bilateral - protrudes mandible (and assists gravity in depressing mandible)
- unilaterally (with medial pterygoid) - laterally deviates mandible to contralateral side
14
Q
what are the muscles of mastication innervated by?
A
these are all innervated by the mandibular division (motor and sensory functions) of the trigeminal nerve (main sensory nerve of the face)
15
Q
what does the oral region include?
A
- oral cavity
- palate
- teeth
- gun - gingivae
- tongue
- oropharyngeal isthmus (fauces)
16
Q
what is the oral cavity divided into?
A
two parts:
1. oral cavity proper - internal to the teeth and gingivae
2. oral vestibule - between teeth and gingivae and the lips and cheeks
17
Q
what are the functions of the oral cavity?
A
- passage for ingested material: hold/ collect ingested material prior to swallowing + begin digestion
- accessory airway - entrance to respiratory tract (indirectly when breathing through the mouth)
- articulation and resonance for speech
18
Q
what are the boundaries of the oral cavity?
A
- roof - palate
- floor - muscles (tongue isn’t the floor but sits on it)
- walls - anterior (lips), lateral (cheeks), posterior (oropharyngeal isthmus (fauces))
19
Q
mucous membranes (mucosa)
A
- lining of oral cavity - it is continuous with mucosa of oropharynx
- contains mucous glands for lubrication
- called gingivae whe it surrounds the teeth
- gigivae + mucosa of the hard palate and tongue are tougher than the mucosa lining the lips and cheeks - allows for greater withstanding of abrasion from ingested material
20
Q
lips (labia) - oral cavity
A
- from anterior wall of the oral cavity
- opening bw then is called oral fissure - formed by musculofibrous tissue
- orbicularis oris muscle + labial muscles
- skin - external surface
- mucosa - internal surface - anchored to the gingivae by the labial frenula ( singular=frenulum)
21
Q
lips (labia) - what are the functions?
A
- articulation of sound and speech
- smiling and sucking liquids
- holding food
22
Q
oral cavity - cheeks (buccae)
A
- form the lateral walls of the oral cavity
- movable walls of the oral cavity and continuous with the lips
- lined by mucosa
- contains fat pads, muscles, nerves and the duct of the parotid gland
23
Q
cheeks (buccae) - function?
A
allow filling of the oral vestibule
24
Q
two types of palates
A
soft and hard palate
25
soft palate
- posterior muscular portion (uvula hanging from end)
26
cleft palate
- birth defect that occurs when the maxillae don’t fuse in utero
- has implications for speech and swallowing
- often associated with cleft lip (incomplete formation of upper lip)
- cleft palate and lip are collective called 'orofacial clefts' and are classified according to location (uni or bilateral) and sverityy ( complete or incomplete)
27
hard palate
-anterior bony portion which covers w mucosa
- has a midline ridge called palatine raphe
- has irregular folds of connective tissue
called palatine rugae > these extend
from anterior palate to area of first
premolar/ highly sensitive/ assist with
speech and swallowing
- has a bony ridge called the alveolar process (or ridge)
28
alveolar ridge - what is it? why have it?
- thickened part of maxillae (+ mandible for lower jaw)
- containing tooth sockets
- covered with gingivae
- essential for healthy teeth and successful dental implants
- important for articulation of alveolar consonants (eg.d/l/n/s/t/z)
29
parts of the tooth
crown
neck
root
30
what is the crown? - tooth
exposed part of the tooth covered by enamel
31
what is the neck? - tooth
narrow part of the tooth bw crown and root - covered by gingivae root is the part of a tooth that is
32
what is the root? - tooth
the part of a tooth that is embedded in the tooth sockets in the alveolar processes/ridges of the maxillae and mandible.
33
what are the types of teeth?
incisors, canines, premolars
34
what are the incisors?
incisors are for cutting food. 2 incisors
in each quadrant of the mouth.
35
what are the canines for?
tearing/shredding food. 1 canine in each quadrant of the mouth.
36
what are the pre-molars for?
crushing/grinding food. 2 premolars in each quadrant of the mouth
37
what are the molars for?
crush/grind food. 3 molars in each quadrant of the mouth. third molars=wisdom
38
tongue - what are the 2 parts?
- can be divided into 2 parts, separated by a V shaped groove called sulcus terminalis
1. oral part - anterior 2/3
2. phrayngeal part - posterior 1/3
-anchored to the floor by the lingual frenulum
39
orophrayngeal isthmus (fauces)
- form from the posterior wall/ boundary of the oral cavity
- narrow passage bw velum and tongue
- boundary between oral cavity and oropharynx
- bound by pillars of fauces/ faucial pillars
40
what are the pillars of the oropharyngeal isthmus (fauces)?
- palatoglossal arch (anterior faucial pillar)
- palatoglossal muscles = covered in
mucosa
- palatopharyngeal arch (posterior faucial pillar)
- palatopharyngeus muscle covered in
mucosa
41
what are the palatine tonsils?
- aggregations of lymphoid tissues
- first line of defence against foreign substances that are ingested or inhaled
42
what are the salivary glands? what do they do?
- produce approx 1- 1.5 L of saliva per day (mostly water)
- cleans and moistens the oral cavity
- maintains oral hygiene - antibacterial properties and neutralises acids
- start digestion
- mechanical - moistens food for bolus production
- chemical - produces enzymes
- dissolves molecules in food for tasting
43
three pairs of major salivary glands
parotid gland
submandibular gland
sublingual gland
44
parotid salivary gland
- largest salivary gland
- located superficially on the face anterior to the ear
- produces mostly serous secretions
- drains its secretion via the parotid duct (crosses masseter muscle) into the oral vestibule, opposite the upper second molar
45
submandibular gland
- produces most of the total saliva
- located deep and inferior to the body of the mandible
- produces a mixture of serous and mucous secretions
- drains its secretions via submandibular duct into the oral cavity proper (under the tongue)
46
sublingual gland
- smallest of the major salivary glands
- located on the floor of the oral cavity under the tongue
- produces mainly mucous secretions
- drains its secretions via the several sublingual ducts into the oral cavity proper (under tongue)
47
salivary glands - innervation
- innervated by the autonomic nervous system
parasympathetic innervation increases salivation
- facial nerve - CN VII- submandibular and sublingual glands
- glossopharyngeal nerve -CN IX- parotid gland
- fibres are carried to the glands via branches of mandibular nerve - CN V3
sympathetic innervation decreases salivation - via vasoconstriction
- results in thicker saliva that is rich in mucous - dry mouth
48
what four cranial nerves that contribute to sensory innervation of oral cavity?
1. trigeminal nerve - CN V
2. facial nerve - CN VII
3. glossopharyngeal nerve - CN XI
4. vagus nerve - CN X
49
zooming in on the trigeminal nerve.... what parts of the face relate to the maxillary/ mandibular nerve?
- maxillary nerve - palate and upper lip and teeth
- mandibular nerve- lower lip and teeth, buccal mucosa, anterior 2/3 of tongue (general sensations)
50
CNs VII, IX, X Nerves
- facial nerve = taste to anterior 2/3 of tongue
- glossopharyngeal nerve = taste and general sensation to posterior 1/3 of tongue and pillars of fauces
- vagues nerve = taste and general sensation to epiglottis and small area of tongue near epiglottis
51
