Salivary Glands Flashcards
Salivary Glands are which subtype of exocrine glands?
Merocrine (They use exocytosis of vesicles and membrane transport of salts and water)
How are Salivary glands structurally laid out?
Compound (Branching) Tubuloacinar
What do Salivary Glands develop from?
Mesenchyme
Parotid and Minor Salivary glands arise from what?
Ectoderm
Submandibular and sublingual arise from what?
Endoderm
What does the Parenchymal tissue (secretory) of salivary glands arise from?
Oral epithelium (ectoderm) or endoderm
What does Stromal tissue (septa and capsule) of salivary glands arise from?
Mesenchyme of mesodermal or neural crest origin
Which salivary glands are first to begin development?
Parotid (6th week) from the crease between maxillary and mandibular swellings.
Which gland is second to begin development?
Submandibular gland (end of 6th/beginning 7th) from sulcus surrounding sublingual folds
Which gland is last to begin development?
Sublingual gland (8th week) from sulcus surrounding sublingual folds (lateral to the submandibular buds)
When do minor salivary glands begin to develop?
Around 12 weeks from both ectoderm and endoderm
Myoepithelial cells arise from what? and when?
Neural Crest around 24-25 weeks to surround acini
What two things is unique about the parotid?
1-Has intraglandular lymph nodes
2-Epithelial buds brand and extend around the facial nerve
What are the 6 stages of salivary gland development?
1-Bud formation
2-Formation and Growth of Epithelial Cords
3-Inititiation of branching in terminal parts of the cord
4-Branching and lobule formation
5-Canalization of presumptive ducts
6-Cytodifferentiation
What happens during Stage 1?
- Mesenchyme induces proliferation in epithelium
- Bud forms
- Bud separates from mesenchyme by basal lamina
What happens during stage 2 ?
- Solid cord forms
- Basal lamina maintained between cord and mesenchyme
What happens during stage 3?
- Proliferation of epithelial cord
- Branching inato terminal bulbs (presumptive acini)
- Formation of first cleft
What happens during stage 4?
- Branching continues at terminal portions to form tree-like system
- CT differentiates around branches
- Formation of lobules
What happens during Stage 5?
- Canalization of epithelial cord
- Lumins appear then branch into ducts
- Tight junctions form between cells
What happens during Stage 6?
- Cytodifferentiation
- formation of functional acini and intercalated ducts
What 3 things can terminal bulb cells differentiate into?
1-Acinar cells
2-Myoepithelial Cells
3- Duct cells
Which collagen type activates branching?
Collagen Type III
Which collagen type(s) maintains and supports branching?
Collagen Types I, IV
What chemical inhibits N-Linked glycosylation?
Tunicamycin (results in decreased epithelial expansion with similar branching amounts)
