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AMIRAH ZAINAB BINTI MAMAT@MUHAMMAD10-3-41
General architecture of the main salivary glands
• Stroma• Parenchyma • Secretory units(acini)• Myoepithelial cells• Types of Acini • Duct System
Stroma • CT component of salivary
gland that support and convey vascular and nervous supply.
• CT tissue capsule- cover and separate
• CT septa (trabeculae)- arise and divide
• Reticular stroma- infiltrated by lymphocytes and plasma cells
Parenchyma• Secretory units
( Acini)• Acini ( blind sac)• Unit structure formed of group
of secretory cells surrounding a lumen and resting on a basement membrane.
• Acini ( serous/mucous/mixed)• Cells are separated from the
basal lamina by modified epithelial cell( basket cells/ myoepithelial cells)
• Myoepithelial cells • Flattened, branched cells with many
processes that acinus like( basket )• Form hemidesmosomal junctions with
basal lamina and desmosomal junctions with acinar and ductal cells they embrace.
• Contain in their cytoplasm abundant actin and myosin filaments which mediate contraction of these cells and squeeze the acinar secretion into the duct.
• Surround also the cells lining the duct system particularly the intercalated ducts. Myoepithelial cells acquire a spindle shape and lie parallel to the length of the duct.
Types of acini found in salivary glands
• Mucous acini • Serous acini• Mixed acini
Mucous acini
Serous Acini
Mixed Acini
Duct system
• The intralobular ducts • The interlobular ducts• The interlobar ducts• The main duct
Intralobular ducts
• Intercalary ducts• thin walled ducts lined by flat or
low cuboidal cells. • Drain the secretory units directly• Represent first segments of the
intralobularducts• Add bicarbonates and adsorb
chlorides from the serous acinar secretion.
• Very short or absent in mucous glands.
• The secretory striated ducts• Intercalary ducts unite together to pour into
larger segments of the intralobular ducts called the secretory striated ducts.
• Salivary glands appear as relatively large, eosinophilic rounded or oval structures with a wide lumen.
• Lined by cuboidal or low columnar cells with indistinct boundaries.
• Have central rounded nucleai and eoisiniophilic granular cytoplasm.
• The basal cell membrane forms deep infoldings lodging mang regularly arranged mitochondria(striated appearance) denote active ion transport across the basal membrane.
• Pump sodium out of the cells and add water to modify saliva as it passes through them.
The interlobular ducts • As terminal part of the
striated secretory ducts leave the lobules, they unit to form larger ducts with a wider lumen.
• Found within the interlobular connective tissue septa between the lobules
• Lined by tall columnar epithelium.
The interlobar ducts
• larger ducts formed by the union of the interlobular ducts as they continue into the interlobar septa between the lobes.
• Lined by tall columnar epithelium
The main duct• Terminal duct of the salivary
gland, which opens into the oral cavity.
• Formed by union of interlobar ducts
• Lined at its beginning by stratified columnar epithelium which gradually becomes non keratinized stratified squamous epithelium similar to that lining the oral cavity where it opens.
References
• http://www.pathologyoutlines.com/topic/salivaryglandsnormalhistology.html
• http://www.vivo.colostate.edu/hbooks/pathphys/digestion/pregastric/salivary.html
• http://www.vetmed.vt.edu/education/curriculum/vm8054/labs/lab17/examples/exglandstruc-7.htm
• http://quizlet.com/13878953/histology-chapter-11-salivary-glands-textbook-and-power-point-and-xerostomia-flash-cards/
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