OB -Salivary glands II -cellular structure and acing secretory mech L3 Flashcards
What are the constituents of salvia?
- water
- inorganic components
- organic components
Name the sequence of ducts from the acinus to the mouth.
- Acinus
- intercalated duct
- striated duct
- secretory duct
what cells are involved in the production of salvia?
cells compromising the acinus (secretory end piece)
what are the 2 types of cells that produce salvia?
- serous
- mucous
what are the shapes of salvia cells?
Pyramidal shaped cells which are polarised for function
Describe the serous acinar cells.
- Nucleus at basal part of cell
- Basophilic RER
- Granular appearance
where do serous acinar cells discharge their secretions?
into the tubular lumen via intercellular canaliculi running between the cells
Describe mucous acinar crells.
- Pale cytoplasm - mucins lost or not easily stained, so cytoplasm can appear empty in a H & E stained section
- Flattened basal nucleus
- Many large mucin granules
What are the serous demilunes that surround the mucous acinar cells?
-Cresent of serous cells
• Mucous acinus capped by serous cells
• Serous cells discharge via intercellular canaliculi between the mucous cells
What is found on acini and intercalated ducts?
myoepithelial cells
What is the function of myoepithelial cells?
• Contractile elements
• “Squeeze”acinus–may assist
secretion
• Regulate duct lumen diameter (make acinus more rigid to prevent over expansion)
why do intercalated duct have myoepithelial cells?
they are fragile and prevent from damage
Describe intercalated ducts.
- Low cuboidal cells
- Large central nucleus
- Difficult to see in routine wax sections
What is function of intercalated ducts?
Only function is to transport salvia from acinus to striated
Describe striated ducts.
• Not present in sublingual glands • Columnar shaped cells • Active modification of primary saliva • Massive basal membrane folding - suggests cells are very active (high metabolic rate)
Describe secretory ducts.
- Large lumen
- Pseudostratified columnar epithelium (layers of cells)
- Stratified near termination – merges with stratified squamous oral epithelium
what is the function of secretory ducts?
Only function is to transport salvia into the mouth
where is the formation of sn isotonic solution?
acinus
what is the name for the isotonic solution of salvia?
primary salvia
what does the Sodium potassium pump do?
pump puts sodium out the cell and brings potassium in the cell
what is stage 1 of producing primary salvia?
Increase in permeability to K+
encourages potassium to leave cell - one potassium in lumen and some outside the basal membrane
what is stage 2 of producing primary salvia?
K+ in the extracellular fluid activates a Na+ K+ Cl- co-transporter (pumped back into the cell)
What is stage 3 of producing primary salvia?
Cl- moves through the apical membrane into the lumen
what is stage 4 of producing primary salvia?
- The increased concentration of Cl- in the acinar fluid drags Na+ to balance the charge
- water then follows sodium