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47 Cards in this Set
- Front
- Back
- 3rd side (hint)
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through what surface do most substances enter the body?
what are it's 4 functions? |
alimentary mucosa
1. secretion 2. absorption 3. barrier 4. immunologic protection |
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what substances does alimentary mucosa secrete?
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digestive enzymes
HCl mucin antibodies |
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2 divisions of oral cavity and what each contains
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Vestibule
- space between lips, cheeks, and teeth Oral cavity proper - behind teeth, bounded by hard and soft palates, tongue and floor of mouth, oropharynx entrance |
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What are the major salivary glands and their ducts?
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1. Parotid Gland
- largest - excretory duct: parotid (Stensen's duct) opens at parotid papilla opposite 2nd molar tooth 2. Submandibular gland - submandibular duct (Wharton's) opens at sublingual caruncle on each side of lingual frenulum 3. Sublingual gland - several excretory ducts, some enter submandibular duct |
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where are the minor salivary glands located?
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submucosa of oral cavity
empty directly via short ducts |
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What is Waldeyer's ring?
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tonsillar ring of immune protection
consists of 4 lymphatic nodules 1. palatine tonsils - entrance to oropharynx 2. tubal tonsils - lateral nasopharynx 3. pharyngeal tonsil (adenoid) - roof of nasopharynx 4. lingual tonsil - base of tongue |
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3 types of mucosa in oral cavity
- location? |
1. masticatory - gingiva and hard palate
2. lining - lips, cheeks, alveolar mucosal surface, inferior tongue, soft palate 3. specialized |
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Masticatory Mucosa
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stratified squamous epithlium
- keratinized (resembles skin but Lacks Stratum Lucidum) - parakeratinized --- superficial cells don't lose nuclei ---cytoplasm doesn't stain intensely with eosin -- lamina propria-- thick layer of loose CT protects it from shearing and frictional stress - at midline (palatine raphe) mucosa adheres to bone - reticular layer of lamina propria blends with periosteum - no submucosa |
2 types
what's underneath? |
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submucosa of masticatory mucosa
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underneath lamina propria
- fatty zone - anterior - glandular zone - posterior, mucous glands continuous with soft palate - thick collagen extends from mucosa to bone |
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Lining Mucosa
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has fewer and shorter papillea - adjusts to muscle movement
- Nonkeratenized with exceptions (may be parakeratinized in some places and keratinized on border of lip) 1. Stratum Basale - single layer of cells on basal lamina 2. Stratum Spinosum - several cell layers 3. Stratum Superficiale - most superficial (surface) layer cells: keratinocytes Langerhan's cells melanocytes Merkel's cells Lamina Propria: - blood vessels - nerves Distinct Submucosa - larger blood vessels -nerves - lymphatic vessels - collagen -elastic fibers - binds mucosa to muscle - contains minor salivary glands - occasional sebaceaous glands (Fordyce spots) |
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Specialized Mucosa
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contains papillae and taste buds
location: dorsal tongue surface |
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lingual muscles
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extrinsic - one attachment outside
intrinsic - all within tongue bundles run in 3 planes - arranged at right angles adipose tissue found among muscle bundles |
types
arrangement |
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sulcus terminalis
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V-shaped depression
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foramen cecum
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remnant of site from which evagination of pharyngeal floor occurred to form thyroid gland
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4 types of papillae
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1. Filiform
2. Fungiform 3. Circumvallate 4. Foliate |
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Filiform papillae
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- smallest
- most numerous - covered with highly keratenized stratified squamous epithelium - only mechanical role, do not contain taste buds - anterior dorsal tongue surface - tips point backward |
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Fungiform papillae
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- taste buds
- stratified squamous epithelium - dorsal surface of tongue - scattered among filiform papillae, project above - more numerous at tip |
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Circumvallate papillae
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- stratified squamous epithelium
- has taste buds - anterior to sulcus terminalis - only 8-10 in humans - lingual salivary glands empty their secretion into base of motes, flush material out |
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von Ebner's glands
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lingual salivary glands with serous secretion
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Foliate papillae
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- lateral tongue: parallel rows of ridges separated by mucosal clefts
- small serous glands empty into celfts |
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3 cell types in taste buds
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1. Neuroepithelial (sensory) cells
2. Supporting Cells 3. Basal cells |
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Neuroepithelial (sensory) cells
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- most numerous
- extend from basal lamina to taste pore - extend microvilli - at apex connected by tight junctions - at base form synapse with processes of sensory neurons of CN VII, IX, X - 10 day turnover |
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Supporting Cells
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- xtend from basal lamina to taste pore
- microvilli and tight junctions - 10 day turnover - DO NOT synapse with nerve cells |
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Basal cells
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- small cells near basal lamina
- stem cells for neuroepithelial and supporting cells |
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locations of taste buds
types of taste detected |
- papillae (except filiform)
- glossopalatine arch - soft palate - posterior epiglottis - posterior wall of pharynx down to cricoid sweet - tip salty - posterolateral bitter - back acid - back (circumvallate) umami |
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lingual tonsil
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- epithelial crypts invaginate into lingual tonsil - invaded with lymphocytes
- between lymphatic nodules it has characteristics of Lining Epithelium - mucous salivary glands within and extend into muscles at base of tongue |
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Tongue Nerve Supply
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motor: glossopharyngeal IX
vascular and glandular innvervation: sympathetic and parasympathetic nerves which innervate blood vessels and salivary glands ANTERIOR 2/3 - general sensation: V3 (trigeminal - mandibular division) - taste: chorda tympani VII POSTERIOR 1/3 - general sensation: glossopharyngeal IX and vagus X - taste: glossopharyngeal IX and vagus X |
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secretory glands
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- surrounded by moderately dense CT
- septa divide gland into lobes and lobules - septa contain blood vessels and excretory ducts - lymphocytes and plasma cells populate the CT |
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what is an acinus
3 types of acini |
blind sac of secretory cells
1. serous: protein secreting - spherical 2. mucous acini: mucin secreting - tubular 3. mixed acini: serous and mucous cells - caps of serous cells called serous demilunes - artifacts of routine fixation formed by expansion of mucinogen |
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basic secretory unit of salivary gland
what it consists of |
salivon
- acinus - intercalated duct - excretory duct |
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Serous Cells
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- protein secreting
- pyramidal shape - rER - free ribosomes - prominent Golgi - numerous spherical secretory granules in apical cytoplasm - near apex joined by junctional complexes |
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Mucous Cells
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- mucin secreting
- cyclic activity - mucous stored in mucinogen granules in apical cytoplasm (lost in prep, looks empty) - apical junctional complex |
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Myoepithelial Cells
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- contractile cells with numerous processes
- move secretory products toward excretory duct - between basal plasma membrane of epithelium and basal lamina - also at proximal portion of duct - sometimes difficult to see in H&E, nucleous small near basement memebrane |
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Salivary Ducts - 3 segments
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1. Intercalated Duct - from acinus, cuboidal epithelial cells
- cells have carbonic anhydrase activity 2. Striated Duct - striations are infoldings of basal plasma membrane of columnar cells 3. Excretory Duct - larger ducts that empty into oral cavity |
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ducts in serous glands
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-well developed intercalated and striated ducts
- modify serous secretion by absorption of components and secretion of additional components |
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ducts in mucous glands
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-poorly developed intercalated ducts
-no striated ducts - secretion is not modified |
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Intercalated ducts
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- cuboidal epithelial cells
- cells have carbonic anhydrase activity - secrete bicarbonate - absorb chloride |
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Striated Ducts
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- cuboidal epithelium that becomes columnar
- striations = infoldings with mitochondria within, due to reabsorption of fluid and electrolytes - centrally located nucleus - reabsorb Na+ (more) - secrete K+ and HCO3- - secretion becomes hypotonic - if secretion is fast less reabsorption and secretion so saliva is more isotonic to hypertonic |
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Excretory Ducts
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- principal duct that connects to oral cavity
- simple cuboidal epithelium changes to psedustratified columar/ stratified cuboidal to stratified squamous near oral epithelium - travel in interlobular and interlobar CT |
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Parotid Gland
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- completely serous
- largest gland - numerous, long, narrow intercalated ducts - large and conspicuous striated ducts - large amounts of adipose tissue - CN VII passes through - can be damaged by mumps (viral infection of parotid) |
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Submandibular Gland
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- mixed, mostly serous
- duct runs lateral to frenulum of tongue - less extensive intercalated ducts |
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Sublingual Gland
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- mixed, mostly mucus
- smallest glands; in floor of mouth - multiple small sublingual ducts empty into submandibular duct and floor of mouth - short or absent intercalated and striated ducts - secretory units may be more tubular |
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Saliva
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- combined secretion of all major and minor glands
- additional sources of saliva: gingival sulcus, tonsillar crypts, general transudation from epithelial lining - 40x more produced than other digestive secretions (1,200mL per day) - contains: water, proteins, glycoproteins, electrolytes - higher K+ and bicarbonate and lower Na+ concentration |
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Functions of Saliva
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1. moisten oral mucosa
2. moisten dry food for swallowing 3. medium for food materials that stimulate taste buds 4. buffer against bicarbonate ions in oral cavity 5. α-amylate digests carbs and continues to act in esophagus and stomach 6. muramidase = lysozyme controls bacterial flora - lyses muramic acid 7. Ca and P used for mineralizationa and repair of tooth enamel |
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acquired pellicle
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protective coat over teeth formed by salivary proteins
- antibodies and other antbacterial agents - without it -> many dental caries |
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salivary immunoglobulin A (IgA)
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- made by plasma cells in CT surrounding acini of salivary glands
- dimeric and monomeric forms released into CT matrix - salivary gland cells make a secretory glycoprotein which is inserted into plasma membrane and serves as receptor for dimeric IgA |
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secretory IgA complex
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- formed when dimeric IgA binds to receptor
- internalized by receptor-mediated endocytosis - carried through acinar cell to plasma membrane -> released into lumen as secretory IgA (sIgA) |
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