Mouth-Tongue Teeth-Esop Dec 2011-2012 SEM II -Prof Farid
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Transcript of Mouth-Tongue Teeth-Esop Dec 2011-2012 SEM II -Prof Farid
1
Human Structure and Function II
Anatomy of the Digestive system
- Oral cavity, tongue and teeth
Captain Assoc Prof. Dr Farid Bin Che Ghazali,
Health campus , Universiti Sains Malaysia.
Semester II
2011 / 2012
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Digestive System: Mouth, Pharynx, Digestive Tube
Plus: Salivary Glands, Pancreas, Liver
Hollow Passage: Mouth to Anus = Digestive Tract
Regional Specializations
Modifications correlate to functions
Functional component = lining (Mucous Membrane)
3
.
ORAL CAVITY
Vestibule
Boundaries
Anteriorly and laterally - lips and cheeks
Posteriorly and medially - teeth and gums
Contents
Termination of the parotid duct
Oral cavity proper
Boundaries
Anteriorly and laterally - teeth and gums
Superiorly - hard palate
inferiorly - tongue and sublingual structures
Posteriorly - palatoglossal and palatopharyngeal arches
Contents
Teeth and gums ,Tongue
Sublingual structures
Frenulum of the tongue,Submandibular ducts & Sublingual folds
Palatine tonsils
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MOUTH & PHARYNX
Mucosa
Stratified squamous epithelium (not cornified)
Basement membrane = basal attachment
Lamina Propria – vascular papillae
Lymphocytic infiltration – pharynx
Lamina muscularis mucosae – absent
Repaced by elastic network (pharynx)
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Submucosa
Lax layer where present
Attaches: mucosa to muscles & bone
Absent on hard palate (part), gums, dorsum of tongue
Glands
Compound tubulo-alveolar
Regional
Serous, Mucous, mixed Sero-mucous
Location: submucosa
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Superficial tissues attached: deep lying skeletal muscle or bone
Blood vessels, lymphatics, nerves:
coarse plexuses
submucosa
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LIP
Outer surface: skin (thin, cornified)
Hair follicles, sebaceous glands, sweat glands
Inner surface: typical mucous membrane
Submucosa: present, not well defined
Stratified squamous epithelium (thicker than epidermis)
Central Core: Skeletal muscle Orbicularis oris; Mimetic
muscles
Labial glands – rounded groups; Sero-mucous (mucous dominant); submucosal
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Transition Zone – at margin
Thick epithelium: much eleidin
Vascular papillae – tall, indent epithelium
Blood capillaries show through epithelium
Glands: absent (drying of lips)
A, Stratified squamous epithelium,
nonkeratinized; B, Lamina propria; C,
Seromucous salivary gland
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CHEEK
Lip plan continued laterally
Mucosa – short papillae; abundant elastic fibers; no glands
Lamina propria – bound to muscle layer (at intervals)
Submucosa: looser, fat-containing
Mixed (largely mucous) glands – invade muscle (M. buccinator)
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GUM
Mucosa attached to alveolar bone
Epithelium moves inward at margin
Gingival Sulcus (~2 mm.)
Bottom of groove – epithelium attached to tooth
Zone of attachment shifts with age
Epithelium resembles labial mucosa
Lamina Propria: dense, fibrous tissue
Binds gum to cementum & alveolar bone
Gum line: papillae very tall, vascular
Zone attachment: no papillae
Mast cells
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TEETH
Tooth = modified soft papilla, hard covering
Hard exposed surface (enamel) – ectodermal
Concealed portion (dentin) – mesodermal
Unique organ – first set replaced by permanent set
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Ground preparation Demineralised preparation
15 Tooth
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Tooth Structure
Free Crown
1 to 3 Roots
Crown – Root junction = Neck
At gum margin
Root in alveolus
Periodontal membrane –
joins root & alveolar wall
Pulp Chamber
Crown into root
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Tooth wall – 3 specialized substances:
1) Dentine – borders pulp
Collagenous mesh
Calcified ground substance
Harder than bone (72% inorganic)
Uncalcified areas (crown) = interglobular spaces
Adjacent to cementum = Granular layer of Tomes
Dentinal canaliculi – radially striate
1 – 3 μ dia.; to 4 mm. long
Lined with Dentinal Sheath of Neumann
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Dentine, continued Dentinal Fiber of Tomes (in canaliculus) = specialized osteoblast = odontoblast
Calcification obliterates
Incremental Lines of Owen & of Ebner
Layered deposits
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2) Enamel – over crown
Hardest tissue – 97% inorganic salts
Calcium phosphate = 90%
Structural unit = Enamel Prism
Enclosed by Enamel Sheath
Prism = separate cell
Entends: dentine to surface
Diameter = 3 – 6 μ
12 million prisms / molar
Cross banded, beaded (surface)
Transverse: hexagonal (humans appear semicircular); bundled
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3) Cementum – over root
Thin layer
Invests denine of root
Bone cells in lacunae; typical bone matrix
Lamellation: inconstant; irregular
Vessels absent
Old age: Haversian systems
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Dental Pulp (“nerve” of tooth – not really “a nerve”
Fills pulp cavity
Soft, gelatinous
Cells: fusiform; stellate – like mesenchymal cells
Reticular fibers in ground substance
Odontoblasts line cavity
cell processes enter dentinal canaliculus
the Dentinal Fibers of Tomes
Also: nerves & blood vessels
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Periodontal Membrane
= periosteum (between alveolar bone & root
Merges with gum; supports gum
Neck region: forms dentinal ligament
Dense, coarse collagenous fibers; Fibroblasts; Osteoblasts
NO ELASTIC FIBERS
Sharpey’s fibers: membrane to alveolar bone; membrane to cementum
= Suspensory Ligament of Teeth
Prof. Madya Dr. Farid Che Ghazali
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TONGUE
Mouth/Pharynx
Mobile organ
Structural: mass of skeletal muscle with mucous membrane covering
Median sulcus – over deep lingual septum
V separates anterior third from posterior two thirds
angle forward
foramen caecum (apex)
Body (oral); Root (pharyngeal)
Lingual papillae – dorsal surface
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Lingual tonsils – dorsum
The Mucosa:
Stratified Squamous Epth.
Tightly bound
Lamina Propria – compact, unites with muscle
Vertical projections with epithelium = lingual papillae 4 types lingual papillae: Filiform, Fungiform, Vallate, Foliate
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Filiform Papillae
= plush of tongue
Parallel rows
Primary columnar elevation of lamina propria
5 – 30 tall secondary papillae
Epithelium over papillae – end in tapered points
“Cat of Nine Tails”
Hard & scaly (not cornified)
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Fungiform Papillae
Knob-like
Scattered, single, among filiform papillae
Larger & fewer than filiform papillae
Narrow stalk, rounded top
Size: 1.8 mm. high; 1 mm. wide
C.T. core; secondary papillae
1 to several taste buds
Modified fungiform papillae: conical (3 mm. high) - few
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Vallate Papillae
V-shaped row; V separates tongue body & root
7 to 11 papillae
Largest papillae: 0.5 to 1.5 mm. high; 1 to 3 mm. wide
Top – below surface of tongue
Trench around periphery
General surface of tongue
Inverted cone shape
C.T. core; secondary papillae
~200 taste buds lateral surface; trench wall ~50
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Number of taste buds highly variable
Von Ebner’s Glands (serous) – may project into muscle
Tongue surface
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Foliate Papillae
Parallel folds; lateral margin tongue
Body-root junction
Regress in adult rudimentary
Infants: 4 to 8; each side tongue
Taste buds – middle region
Von Ebner’s glands open into bottom of trench
Rabbits: highly developed
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Taste Buds
Taste buds are most numerous in the fungiform,
circumvallate and foliate papillae. In addition,
taste buds are found in the palate, palatoglossal
and palatopharyngeal arches and in the pharynx
and larynx.
In histological sections they appear as ovoid
lightly stained bodies, which extend
perpendicular from the basement membrane to
a little opening formed in the epithelium, the
taste pore. The elongated cells that form the
taste bud can functionally be divided into three
groups: sensory cells, supporting (or
sustentacular) cells, and basal cells. Sensory
cells extend microvilli into the taste pore. These
microvilli contain the receptors for the different
basic taste modalities (sweet, salty, bitter and
acid). Basal cells regenerate the two other cell
types.
(Cell turnover is quite high, and it is thought that
the cells of the taste buds are replaced (on
average) every 10th day).
Prof. Madya Dr. Farid Che Ghazali
34
Lingual Glands
Several sets: Anterior; Glands of Von Ebner; Mucous Glands of the Root
Anterior Glands: under apex of tongue
mixed sero-mucous glands
several ducts/gland group
Glands of Von Ebner: near vallate & foliate papillae
purely serous
4 to 38 ducts (vallate trenches)
Mucous Glands of Root
lymphoid area into body
purely mucous
ducts into pits lingual tonsils
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Muscle
halved incompletely (fibrous lingual septum)
Skeletal muscle – 2 groups
Intrinsic group: M. lingualis, confined to tongue
Extrisic group: arise outside tongue; insert into tongue
hyoglossus, genioglossus, styloglossus, palatoglossus, chondroglossus
Fibers in bundles: all directions, common direction in bundle
Fibers: in loose, fatty areolar C.T.
Insertion: perimysial C.T.
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Blood Vessels:
plexus in lamina propria
capillaries into papillae
Lymphatics:
drain papillae plexus in lamina propria
Nerve Fibers:
Efferent nerve fibers: muscle, glands, blood vessels
Sensory nerve fibers: end freely, general sensibilities; taste buds (= gustatory)
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Palate
Roof of mouth
2 sides: oral, nasal
Oral side: oral type mucosa
Nasal side: respiratory mucosa
Uvula (conical) – at end
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Hard Palate
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Hard Palate:
Oral Side:
Stratified squamous epithelium
tall papillae – densely fibrous lamina propria
Submucosa: except at raphe
Anterior 1/3 fatty
Posterior 2/3 pure mucous glands
Middle layer: maxillary & palate bones
Nasal Side:
Pseudostratified columnar epithelium, ciliated
Mixed sero-mucous glands
deep elastic fibers
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Soft Palate:
Continuation of hard palate
Oral side similar to hard palate
lamina propria infiltrated with lymphocytes
Dense layer elastic fibers between mucosa-submucosa
Middle layer: skeletal muscle
Nasal side similar to hard palate
exception: near free margin: stratified squamous epithelium
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Pharynx
Flattened, conical chamber
Superior & Inferior regions
Superior = respiratory – naso-pharynx
Nasal mucosa
Inferior = oro-pharynx (behind palatine arches); laryngo-pharynx
Tonsilar ring at beginning
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Epithelium:
naso-pharynx: pseudostratified columnar, ciliated; specialized goblet cells
Changes at lower levels to: stratified columnar then stratified squamous
oro- & laryngo-pharynx: soft, stratified squamous
Lamina Propria:
naso-pharynx basement membrane distinct
C.T. papillae
Oro- & laryngo-pharynx: scattered, solitary lymph nodules
deepest layers: thick elastic layer
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Submucosa:
Well developed: naso-pharynx (laterally); near esophagus
Other regions: elastic layer against muscle
Small mucous glands – regions of stratified epithelium
Musclularis:
2 layer (skeletal muscle)
Inner longitudinal; outer oblique/circular
Adventitia:
thin, fibrous (most regions)
other regions: muscles attached to bones of skull
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Pharyngotympanic tube
Auditory tube
Eustachian tube
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Oropharynx
• Digestive function
• Anterior: anterior tonsillar pillar
• Posterior: superior constrictor
• Superior: soft palate
• Inferior: base of tongue, superior epiglottis
• Laterally: palatoglossal and palatopharyngeal arches
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Epiglottis
This is a slightly curved, leaf-
shaped structure, the stalk of the
epiglottis is attached to the deep
aspect of the laryngeal
prominence.
This cartilage overhangs the
ventricle of the larynx.
The epiglottis is connected to
the: Tongue by the median and
lateral glossoepiglottic folds.
Arytenoids cartilages by the
aryepiglottic and false vocal
folds.
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Palatine Tonsil…
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Lingual Tonsil
Lymphatic nodules at arrows
Several lymphoid follicles, which represent a portion of the lingual tonsil, are
present. They protrude slightly above the surface of the posterior tongue. Variable
distribution extending to epiglottis or the palatine tonsil.
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Pharyngeal Tonsil
Respiratory epithelium
Pharyngeal tonsils
resemble those of
the palate but with
ciliated,
pseudostratified
epithelium rather
than stratified
squamous
epithelium lining the
surface and crypts.
51
A, Condylar head; B, Tubercle of temporal bone; C, Articular fossa;
D, Articular disk; E, Upper synovial cavity; F, Lower synovial cavity;
G, Lateral pterygoid muscle; H, Upper portion of posterior disk and
capsule; I, Lower portion of posterior disk and capsule
• The Pharyngeal walls made up of mucosa, submucosa,
pharyngobasilar fascia, constrictor m., buccopharyngeal
fascia
• Lateral walls made up of ant. and post. tonsillar pillars,
tonsillar fossa with the palatine tonsil, lateral phayngeal
wall
• Soft palate made up of palatine aponeurosis, tensor and
levator veli palatini, uvular m, palatoglossus,
palatopharyngeus
Important notes