Salivary Glands Flashcards
what are the functions of saliva
speech, mastication, swallowing, taste, digestion, protection, buffering, antimicrobial action, maintenance of tooth integrity, soft tissue repair
what is taste function in saliva due to
protein gustin that is necessary for growth and maturation of taste buds
what is digestion function in saliva due to
salivary amylase that degrades starch
what is protection function in saliva due to
lubrication protects lining mucosa form noxious stimuli, bacterial toxins, and minor trauma
-washing action to rid mouth of non-adherent bacteria
-clears sugars from mouth
what does the buffering function of saliva do
prevents potential pathological bacteria from colonizing the mouth
- buffering of microbial acids
-sialin: protein that raises pH of dental plaque after exposure to fermentable carbohydrates to even things out
what is the antimicrobial action of saliva due to
lysozyme: hydrolyzes bacterial cell walls
lactoferrin: binds free iron and thereby deprives bacteria of an essential nutrient
salivary IgA: causes bacterial clumping (agglutination)
how does the maintenance of tooth integrity function in saliva work
calcium and phosphate ions facilitate mineralization of tooth surface
how does soft tissue repair function occur in saliva
via epithelial growth factor and clotting factors
what are ectomesenchymal cells
undifferentiated cells that cause invagination of oral eptihelial cells
what do ectomesenchymal cells do
dictate differentiation of oral epithelium which in turn proliferates and grows into the underlying mesenchyme
what do the epithelial buds of ectomesenchymal cells form
-alveoli that develop into acinar cells (form serous, mucous, or sero-mucous product)
-epithelial cords that develop into salivary ducts
what do serous alveoli contain? mucous?
serous: water based
mucous: contain protein mucin
what are the 5 stages of salivary gland development
- induction of oral epithelium by underlying ectomesenchyme
- growth of the epithelial cord
-initiation of epithelial cord branching
- repetitive branching and lobule formation
- canalization of the presumptive ducts
- cytodifferentiation of the ducts at the tips to become acinar cells, myoepithelial cells, and ductal cells
salivary gland development is done with the help of what??
FGF and EGF
what happens in the development process of salivary glands
FGF and EGF act on terminal bulb that can differentiate into either acinar cells, myoepithelial cells and/or duct cells
what is the process timeline in the development process of salivary glands
- 6th week of development: parotid and submandibular gland
- 8th week of development: sublingual gland
- 10th week of development: minor salivary glands
where are myoepithelial cells found and what do they do
envelope acinar cells
- they are smooth muscle contractile cells that help with secretory process. contract and squeeze mucous contents into the gut
where are ductal cells located
intercalated duct -> striated duct -> collecting duct
describe the appearance of glands
lobular in appearance and contain septa that form borders of lobules
what is the order of ducts starting with the acinus
intercellular canaliculus -> intercalated duct -> striated duct -> excretory duct
-> terminal excretory duct
where are intercellular canaliculi located and what happens in them
- in between acinar cells. contain villi
- water passes freely throughout the membrane and proteins are secreted and exchanged in granule forms
what are intercalated ducts lined with and what is its function
lined with cuboidal cells
- unknown function- may have backup function, stem cells to replace acinar cells
where are striated ducts located and what is their function
-location: where EGF is secreted to help with differentiation of terminal bulb cells
-function: have microvilli involved in electrolyte resorption. Na and Cl resorbed and K and bicarbonate secreted into duct
describe the excretory duct
smooth duct with flat cells and no villi
