Week 11 - Salivary Glands Flashcards
What are the function of saliva?
speech, mastication, swallowing, taste, digestion, protection, buffering, antimicrobial action, maintenance of tooth integrity, soft tissue repair
What protein is involved in taste?
gustin that is necessary for growth and maturation of taste buds
What is digestion due to?
salivary amylase that functions in degrading starch
What does protection do?
lubrication protects lining mucosa from noxious stimuli, bacterial toxins, and minor trauma
How does lubrication with protection work?
- Washing action to rid mouth of non-adherent bacteria
- Clears sugars from mouth
What is the function of buffering?
prevents potential pathologic bacteria from colonizing the mouth, most require a specific pH
What exactly gets buffered?
Buffering of microbial acids (bicarbonate and phosphate ions)
What does sialin protein do?
protein that raises pH of dental plaque after exposure to fermentable carbohydrates to even things out
What are things involved in antimicrobial action?
Lysozyme
Lactoferrin
Salivary IgA
What is the function of lysozyme?
Hydrolyzes bacterial cell walls
What is the function of lactoferrin?
binds free iron and thereby deprives bacteria of an essential nutrient
What is the function of salivary IgA?
causes bacterial clumping (agglutination)
What is the maintenance of tooth integrity?
calcium and phosphate ions facilitate mineralization of tooth surface
How is there soft tissue repair?
via Epithelial growth factor and clotting factors
What are ectomesenchymal cells?
undifferentiated cells that cause invagination of oral epithelial cells
What do ectomesenchymal cells dictate?
differentiation of oral epithelium which, in turn, proliferates and grows into the underlying mesenchyme
The epithelial buds undergo histo-differentiation and morpho-differentiation to form assemblies of:
- Alveoli that develop into acinar cells (form serous, mucous or sero-mucous product)
- Serous: water based
- Mucous: contains protein mucin
- Sero-mucous: combination
- Epithelial cords that develop into salivary ducts
What are the stages of salivary gland development?
- Induction of oral epithelium by underlying ectomesenchyme (initial invagination of cells)
- Growth of the epithelial cord (eventually becomes duct)
- Initiation of epithelial cord branching
- Repetitive branching and lobule formation
- Canalization of the presumptive ducts (apoptosis occurs to make ducts hollow)
- Cytodifferentiation of the ducts at the tips to become acinar cells, myoepithelial cells (small muscle cells), and ductal cells
What does Cytodifferentiation of the ducts at the tips done with the help of?
FGF (fibroblast growth factor) and EGE (epidermal growth factor)
What is the development process of salivary glands? what do they differentiate into?
FGF and EGF act on terminal bulb cells (undifferentiated cells) that can differentiate into
1. Acinar cells
2. Myoepithelial cells
3. Duct cells
What is the process timeline of the development process?
6th week of development for parotid and submandibular gland
8th week of development for sublingual gland
10th week of devepopment for minor salivary glands
What are myoepithelial cells?
envelope acinar cells. They are smooth muscle contractile cells that help with secretory process. Contract and squeeze mucous contents into the gut
What are ductal cells?
Intercalated duct (tends to have myoepithelial cells present) -> striated duct -> collecting duct (take salivary fluids to destination)
Describe the appearance of glands
lobular in appearance and contain septa that form borders of lobules
What is the hierarchy of ducts
Intercellular canaliculus
Intercalated duct
Striated duct
Excretory duct (aka collecting duct)
Terminal excretory duct
What are intracellular canaliculus?
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 cuboidal cells. Unknown function
May have backup function, stem cells to replace acinar cells
What are striated ducts?
Striated duct Have microvilli involved in electrolyte resorption
Na and Cl: resorbed
K and bicarbonate: secreted into duct
Location where EGF is secreted to help with differentiation of terminal bulb cells
What are excretory duct/collecting ducts?
Smooth duct with flat cells and no villi
What are the three major salivary glands?
consist of parotid, submandibular, and sublingual glands
Where does parotid gland exit out of?
Stenson’s duct
Where is the parotid gland near?
1st and 2nd max molars
What does the parotid gland secrete?
Purely serous
What is the parotid gland responsible for?
20% of unstimulated salivary flow
What does salivary gland enlargement occur?
parotitis (mumps) Sjögrens syndrome, bulimia nervosa, anorexia nervosa, benign and malignant neoplasia
What is the parotid gland histologically?
contains dark acinar, due to serous granules continuing proteins
Where does the submandibular gland exit out of?
Wharton’s duct
Where is the wharton’s duct?
Just under tongue (sublingual caruncle)
What does the submandibular gland secrete?
Mixed serous gland (predominately serous with some mucous contributions)
What is the submandibular gland responsible for?
60% of unstimulated salivary flow
What does the submandibular gland contain?
serous demilunes (half-moon shape of serous cells, providing serous contributions to the mucous acinus)
What does the sublingual gland exit out of?
Bartholin’s duct
Where is bartholin’s duct located?
posterior to Wharton’s duct near sublingual caruncle
What does the sublingual gland secrete?
Mixed mucoserous gland (predominanrly mucous secreting with some serous contributions)
What is the sublingual gland responsible for?
10% of unstimulated salivary flow
What does the sublingual gland contain?
Serous demilunes
What do minor salivary glands account for?
10% of unstimulated salivary flow
What do most minor salivary glands secrete?
Mucous
What happens if minor salivary glands get plugged?
Can get severed
What are von ebner’s glands?
pure serous gland associated with circumvallate papillae. Once they are stimulated, they send out secretions to wash away food from taste buds (clears out crypts of taste buds so they can continue to taste food)
What are blandin-nuhn glands?
mucoserous glands located on ventral surface at tip of tongue
What are weber’s glands?
mucous glands associated with the pharyngeal tonsils
What are carmalt’s glands?
mucous glands found in the mandibular retromolar area
What do endocrine glands secrete?
Product secreted into blood and affects other cells
No duct system (directly into blood)
What do exocrine glands secrete?
Secrete product onto a surface
Usually has a duct
What are merocrine glands?
Little to no damage to secreting cells (salivary glands)
What are apocrine glands?
Partial injury to secreting cells as secrete product (mammary/sweat glands)
What are halocrine glands?
Total destruction of secreting cells as they secrete product (sebaceous glands)
What are fordyce granules?
Not a pathologic lesion, considered normal anatomy
Represent ectopic sebaceous glands
Fordyce granules
What is nicotine stomatitis?
Due to smokers (pipe smokers usually due to increased heat)
May be reaction to heat. Inflamed and ulcerated salivary glands. Results when patients stop smoking
Nicotine stomatitis
What is salivary gland mucocele a result of?
The result of trauma that severs the duct resulting in extravasation of mucin into the surrounding soft tissues
What is the most common site of occurrence of a salivary gland mucocele?
lips, tip of ventral surface of the tongue, soft palate
- In line with occlusal plane, usually due from trauma (biting down on lip) that severs the duct
What are salivary gland mucoceles characterized by?
accumulation of mucin containing numerous foamy histiocytes (macrophage precursor, resident immune cells) that cause inflammation response surrounded by granulation tissue
Salivary gland mucocele
What is ranula?
Mucocele that occurs in the floor of the mouth
What do ranula’s most often involve?
the sublingual salivary gland. Can increase or decrease in size during feeding times (usually increased)
Ranula
What is sjogren’s syndrome?
Chronic, systemic autoimmune diseases
Who does sjogren’s syndrome occur in?
80-90% of cases occur in middle aged to older females
What are clinical signs of sjogren’s syndrome?
Clinical signs and symptoms xerostomia, xerophthalmia (dryness of eye), keratoconjunctivis sicca (scaring of conjunctiva)
What is sjogren’s syndrome due to?
Parotid gland swelling due to lymphocytic and plasma cell infiltrate/attack
Sjogren’s syndrome
What is mixed tumor (pleomorphic adenoma)?
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 are mixed tumor (pleomorphic adenoma) histologically described as?
well circumscribed and encapsulated, tissue is derived from mixture of ductal and myoepithelial cells (keratinizing squamous cells and mucous producing cells are also present)
Mixed tumor (pleomorphic adenoma)
What is One of the most common salivary gland malignancies?
Mucoepidermoid carcinoma
What gland does mucoepidermoid carcinoma most commonly invovlve?
The parotid gland
What do patient tend to have in Mucoepidermoid carcinoma?
pain or facial nerve palsy (CN VII)
What is seen histologically in 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
Cells of all different shapes and sizes are present
Mucoepidermoid carcinoma
