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
what are the 3 major salivary glands
parotid, submandibular and sublingual glands
where does the parotid gland exit
stensons duct near 1st and 2nd maxillary molars
what type of gland is the parotid gland and how much unstimulated salivary flow is it responsible for
pure serous gland
- 20%
when does enlarged parotid gland occur
sjogrens syndrome, bulimia nervosa, anorexia nervous, benign and malignant neoplasia
what is the histological appearance of the parotid gland
contains dark acinar, due to serous granules containing proteins
where does the submandibular gland exit at
at whartons duct just under the tongue
what type of gland int he submandibular gland and what portion of unstimulated salivary flow is it responsible for
-mixed serous gland
-60%
which glands contain serous deminlunes
submandibular and sublingual gland
where does sublingual gland exit
bartholin’s duct, posterior to whartons duct near sublingual caruncle
what type of gland is the sublingual gland and what portion of unstimulated salivary flow is it responsible for
mixed mucoserous gland
- 10%
what percentage of unstimulated salivary flow are minor salivary glands responsible for
10%
what type of glands are minor salivary glands
mostly mucous
what is von ebners gland and what do they do
pure serous gland associated with circumvallate papillae. once they are stimulated they send out secretions to wash away food from taste buds
what type of gland is blandin-nuhn gland and where is it located
mucoserous gland located on ventral surface at tip of tongue
what type of gland is Weber’s gland and where is it located
mucous gland associated with pharyngeal tonsils
what type of gland is carmalt’s gland and where is it located
mucous gland found in the mandibular retromolar area
what is an endocrine gland and does it have a duct system
-product secreted into blood and affects other cells
- no duct system
what is an exocrine gland and does it have a duct system
-secrete product onto a surface
-usually has a duct
what do merocrine glands do and where are they located
-little to no damage to secreting cells
-salivary glands
what do apocrine glands do and where are they located
-partial injury to secreting cells as secrete product
-mammary and sweat glands
what do halocrine glands do and where are they located
total destruction of secreting cells as they secrete product
-sebaceous glands
what are fordyce granules
- represent ectopic sebaceous glands
-not pathologic
what is nicotine stomatitis and what is it caused by
-reaction to heat- inflammed and ulcerated salivary glands
- smokers
what is a salivary gland mucocele caused by
result of trauma from biting down that severs the duct resulting in extravasation of mucin into the surrounding soft tissues
where is the most common site of occurrence of the salivary gland mucocele
lips, tip of ventral surface of the tongue, soft palate. in line with the occlusal plane
what is a salivary gland mucocele characterized by
an accumulation of mucin containing numerous foamy histiocytes that cause inflammation response surrounded by granulation tissue
what is a ranula and what other structure does it involve
-mucocele that occurs in the floor of the mouth
- often involves the sublingual salivary gland
- can increase or decrease in size during feeding times
what is sjogrens sydrome, incidence, and symptoms
-chronic, systemic autoimmune disease
- 80-90% of cases occur in middle aged to older females
-clinical signs: xerostomia, xerophthalmia, keratoconjunctivitis sicca, parotid gland swelling due to lack of lymphocytic plasma cell infiltrate
what is a mixed tumor/pleomorphic adenoma and incidence of gland tumors
-benign tumor that accounts for 53-77% of parotid gland tumors, 44-68% of submandibular gland tumors, and 38-43% of minor salivary gland tumors
what is the histological appearance of a pleomorphic adenoma
well circumscribed and encapsulated tissue is derived from mixture of ductal and myoepithelial cells
what is a mucoepidermoid carcinoma
- one of the most common salivary gland malignancies
- most commonly involved the parotid gland
- involves pain or facial nerve palsy
what is the histological appearance of a mucoepidermoid carcinoma
composed of a mixture of mucous producing cells and squamous epidermoid cells. abundant cellular pleomorphism and a tendency to form cystic areas within the tumor cell mass
