SFP: histology of salivary glands and exocrine pancreas Flashcards
Briefly describe exocrine glands
They retain contact with surface epithelium; their ducts lead to body surface or another organ
What kind of exocrine gland is found in the exocrine pancreas?
Acinar
What kind of exocrine glands are found in the salivary glands?
Tubuloacinar
Is saliva acidic or alkaline?
Alkaline
What are the major salivary glands?
Parotid, submandibular, sublingual
Describe serous cells of salivary glands
Protein-secreting cells that have a pyramid shape and apical secretory granules
What kinds of junctions are found between serous cells?
Tight and adherent
Describe mucous cells of salivary glands
Columnar shaped cells with flattened nuclei at the base and apical granules with mucins
What are myoepithelial cells of salivary glands?
They contain actin and myosin and extend contractile processes around associated secretory units/ducts to help propel products through the duct
Where are myoepithelial cells found?
Inside basal lamina surrounding acini, tubules, and proximal ends of the duct system
What is a salivon?
The secretory unit of a salivary gland
What is the difference between intercalated ducts and striated ducts?
Intercalated ducts are incorporated into the gland, while striated ducts are formed by several intercalated ducts
What is the epithelium of intercalated ducts?
Cuboidal
What is the epithelium of striated ducts?
Columnar
Striated and intercalated ducts are both ___
Intralobular
Describe the basic structure of striated ducts
Contain infoldings of basolateral membranes aligned with mitochondria
What is the significance of infoldings in striated ducts?
They increase surface area for reabsorption of sodium ions
Intralobular ducts drain into…
Interlobular ducts (excretory ducts)
Describe excretory ducts
They increase in size and thickness of connective tissue along and along, and may have a variety of epithelium types
What is the epithelium in the main excretory duct of the salivary gland?
Nonkeratinized stratified squamous epithelium
Parotid glands are made of __ acini
Serous; they only secrete serous fluid/proteins!
What do parotid glands release?
Alpha amylase and other protein rich proteins
What do submandibular glands release?
Mucus and proteins; sialomucins, alpha amylase, lysozyme
Submandibular glands are made of __ acini
Pure serous and mixed seromucous
What are serous demilunes?
Crescent shaped groups that serous cells are found in within submandibular glands
Sublingual glands are made of ___ acini
Mucous and serous, but mostly mucous
What do sublingual glands release?
Sialomucins, alpha amylase, lysozyme
What is a histological clue for sublingual glands?
Bundles of skeletal muscle
Describe primary saliva
It is isotonic with blood when produced, but slightly hypotonic when released into the oral cavity
What may regulate electrolyte balance in the saliva?
Aldosterone
How does the PSNS impact saliva?
Leads to copious amounts of watery secretion!
How does the SNS impact saliva?
Inhibits secretion, leading to low amounts of viscous saliva
What is sjogrens syndrome?
Autoimmune disorder that attacks salivary glands and decreases the ability to produce saliva
All the secretion in the pancreas is…
Serous
Briefly describe the glands in the exocrine pancreas
Serous acini but no myoepithelial cells and no striated ducts!
What is special about cells of glands in the pancreas?
They’re polarized! They basal cytoplasm is basophilic from a bunch of rough ER and the apical cytoplasm is eosinophilic from zymogen granules
What digestive enzymes are secreted by the exocrine pancreas?
Proteases, alpha amylase, lipases, nucleases
Proteases from the pancreas are secreted as…
Inactive zymogens
Describe the activation of trypsin
Trypsinogen is released into the duodenum by the pancreas, where it is activated by enteropeptidases to generate trypsin. Trypsin sets off a cascade to activate other inactive zymogens
Describe cholecystokinin
It is made by enteroendocrine cells of the small intestine and stimulates enzyme secretion by pancreatic acinar cells
Describe secretin
It is made by enteroendocrine cells of the small intestine and promotes water and bicarb secretion by duct cells
What mechanism can bypass CCK and secretin?
PSNS activation
What are centroacinar cells?
Cells that are the beginning of intercalated ducts that extend into the acinus in the pancreatic glands
The acinus in the pancreatic glands is drained by…
Intercalated ducts
Describe the movement from acinus to secretion in the pancreas
Acinus, intercalated duct, intralobular ducts, interlobular ducts, main pancreatic duct
How can we distinguish intralobular and interlobular ducts histologically?
Interlobular ducts have a rim of dense connective tissue
