pete smith senior lecturer in oral biology /...
TRANSCRIPT
Pete Smith
Senior Lecturer in
Oral Biology / Physiology
1st BDS Teaching Lead
School of Dentistry
www.petesmif.org.uk
Ingestion of a meal
• Mastication
• Salivary glands and salivation
• Deglutition
• Salivary gland pathology
Muscles of Mastication
temporalis
Masseter: arises from the zygomatic process of the maxilla and inserts into the angle and ramus of the mandible
Temporalis: arises from the temporal fossa and inserts onto the coronoid process of the mandible
mandible
hyoid
maxilla
temporal
Muscles for closing the mouth
Muscles of Mastication
temporalis
lateralpterygoid
Digastric: posterior: arises from the mastoid notch; anterior arises from lower border of the mandible. Insert onto the hyoid
Lateral pterygoid: arises from the sphenoid and inserts onto the condyloidprocess of the mandible
Infrahyoid: (4 pairs if muscles) arise from hyoid insert onto clavicle (ish). All of the muscles of
mastication are innervated by the mandibular branch of the trigeminal nerve
mandible
hyoid
maxilla
temporal
Muscles for opening the mouth
Control of Mastication
• Voluntary
• Reflexes: Jaw opening reflex; Jaw-jerk reflex
• Brain stem pattern generator
• Fine tuning via sensory feedback through periodontal ligaments and proprioceptors
• A change in occlusion (e.g. following dentistry) will alter the chewing pattern.
• There are 3 main movements of mastication
Movements of Mastication
The temperomandibular joint (TMJ) allows three movements of mastication:
open/close; protrusion/retraction; lateral
Salivaryglands
submandibularsublingual
parotid
Salivation
SalivaryNuclei
mastication
+VII
IX
tastesmell
anticipation
-
fear
Superior (pons)
Inferior (medulla)
• Tooth maintenance
• Lubrication
• Antibacterial/antifungal
• Digestive
Functions of Saliva
: salivary amylase; lingual lipase
: allows speech, mastication and deglutition
rampant caries
candida infection
• Tooth maintenance
Functions of Saliva
: dilution, clearance and buffering
0 20 40
Time (seconds)
Pla
qu
e p
H
5
5.5
6
6.5
7
Stephan Curve
Critical pH
teeth demineralise
rampant caries
• Lubrication
Functions of Saliva
: salivary glycoproteins are sticky
• Antibacterial/antifungal
Functions of Saliva
: protective barrier; IgA; lysozyme etc.
Saliva and Oral Health
4th Edition
ISBN: 9780956566836
Paperback: £25.00
Saliva and Oral Health
3rd Edition
Many copies available in the library
Much more detail available in:
Salivary Secretion
Parotid
submandibular
sublingual
serous
mucous
mixed
All salivary glands secrete both protein and fluid.The constituency of saliva is determined by the nature of the secreted protein
minor glandsmucous
myoepithelia cell
Striated duct
Excretory duct
Mucous acinus
Serous acinus
Intercalated duct
Serous demilune
endoplasmic reticulum
nucleus
secretory vesicles
apical or lumenal side
basolateral or blood side
noradrenalin
fluidprotein
cyclic
adenosinemonophosphate
cAMP Ca2+
acetylcholine
sympathetic nervous system parasympathetic nervous system
Stimulus-
Secretion
Coupling
b adrenergic receptor
G-protein
adenylate cyclase
CHOH CH NH. .2 2
OH
OH noradrenaline
OH
C
PO4
NH2
cyclic AMP
Protein
Secretion
cAMP stimulates
gene transcription,
glycosylation and
formation of
secretory vesicles
and exocytosis
RR
Polymeric immunoglobulin receptor
PIgR
R
IgA
Transcellular translocation of serum IgA
M3 muscarinic receptor
G-protein
phospholipase C
acetylcholine
inositol 1,4,5 trisphosphate
IP3
N CH CH O CO CH. . . . .2 2 3
CH3
CH3
CH3
Fluid
Secretion
Na+Cl-
K+N CH CH O CO CH. . . . .
2 2 3
CH3
CH3
CH3
Ca2+ release
osm
otic
gra
die
nt
NaCl
receptor
activationIP3
increased
[Ca2+]i
ion channel
activation
fluid & electrolyte
secretion
Deglutition
• Oral/buccal: voluntary: the bolus is pushed to the back of the mouth by the tongue. The teeth are brought together. The soft palate elevates to close the nasal cavity. The larynx rises to close the airways (inspiration is inhibited)
• Pharyngeal: involuntary (reflex): cricopharyngeal sphincter relaxes to open the oesophagus. The epiglottis steers the bolus over the trachea and the peristalsis starts
• Oesophageal: peristalsis; all of the above reverse….
: an autoimmune condition that causes salivary gland dysfunction and atrophy
• What causes xerostomia?
• Drugs
• Disease• Sjogren’s syndrome
Salivary gland pathology
rampant caries
www.petesmif.org.uk
Much more detail available via: