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Components of the digestive system:
- 1. Digestive tract (alimentary canal): oral cavity, pharynx, esophagus, stomach, small intestine, large intestine
- 2. Accessory digestive organs: teeth, tongue, salivary glands, liver, biliary ducts and gall bladder, pancreas
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Oral Cavity (buccal cavity; 'mouth'):
- oral mucosa ‑ stratified squamous epithelium (nonkeratinized)
- oral cavity proper
- vestibule
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Palate:
- hard palate (bone)
- soft palate (muscle)
- uvula
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Fauces:
- anterior (palatoglossal) arch
- posterior (palatopharyngeal) arch
- palatine tonsil
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Tongue:
- frenulum
- anterior 2/3 (body): mobile
- posterior 1/3: (root): attached to hyoid bone
- taste bud structure
- lingual tonsils
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muscles of the tongue:
- extrinsic: main movements (genioglossus)
- intrinsic: alter shape
- all supplied by hypoglossal (XII) nerve
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papillae of tongue: filiform, fungiform, circumvallate
- filiform (elongated) ‑ stratified squamous epithelium (keratinized)
- fungiform (mushroom‑shaped) ‑ dorsal tastebuds
- circumvallate (dome‑shaped) ‑taste buds in wall of trough
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Salivary Glands:
- minor salivary glands (lips, cheeks, palate)
- major salivary glands:
- parotid:
- parotid (Stensen's) duct
- serous acini
- submandibular:
- submandibular (Wharton's) duct
- serous acini and mucous acini
- sublingual:
- sublingual ducts
- mucous acini
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Teeth:
- deciduous (20): 2 incisors, 1 canine (cuspid) , 2 molars in each half jaw
- permanent (32): 2 incisors, 1 canine (cuspid), 2 premolars (bicuspids), 3 molars in each half jaw
- eruption times (roughly in multiples of 6 ‑ lowers appear before uppers):
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eruption of deciduous teeth:
- first incisor: 6 months
- first molar: 12 months
- all appear by: 24 months
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eruption of permanent teeth:
- first incisor, first molar: 6 years
- second molar: 12 years
- all anterior to second molar by 12 years
- third molar (wisdom): approximately 24 years
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tooth structure:
- alveolus (socket)
- gum
- gingiva
- gingival sulcus
- crown, root and neck
- dentin
- enamel
- pulp cavity
- periodontal ligament
- cementum
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