EXAM III Digestive Flashcards
Desribe the general histological organization of the pancreas
Lobulated
Compound
Tubul-alveolar gland
Exocrine and Endocrine secretory function
Contains a Connective Tissue support
No organized capsule, thin layer of CT where septa divides into many lobules
Describe intercalated ducts and their secretion
Lined with low cuboidal cells that contain receptros for secretin
Cells secrete water and bicarbonate ions
Describe the histology of the pancreatic acinus, what is its function?
Pyramidal serous cells w/ a basophilic basal zone with a nucleus and RER
Apical zone w/ zymogen granules
Precursors of pancreatic juice enzymes =
Trypsin, chymotrypsin, amylase, lipase
Specific receptors for CCK
No striated ducts or myoepithelial cells
Release of digestive enzymes from serous acinar cells that are stimulated by CCK
What is the function of acinar?
Releases digestive enzymes from serous acinar cells stimulated by CCK
Trypsin
Chymotrypsin
Amylase
Lipase
What is the function of centroacinar?
Stored in vesicles as zymogen granules
Synthesis & secretion controlled by peptides that are secreted by duodenal enteroendocrine cells
Synthesized as inactive proenzymes on RER of acinar cells
Forms a truncated cuboidal epi w/ lumen of acini
Continuous w/ epi of the intercalated duct
What is the function of ductal epithelial cells?
Releases bicarbonate-rich alkaline fluid in response to secretin
What is the action of secretin and CCK on pancreatic acini?
Secretin - stimulates ductal epithelial cells to release bicarbonate-rich alkaline fluid
CCK - stimulates the release of digestive enzymes from serous acinar cells
What is the synthetic pathway of pancreatic bicarbonate ions?
CO2 diffuses into intercalated ducts from the blood and combines with water to form bicarbonate via CA then HCO3 and H+
Bicarbonate is actively transported to lumen of intercalated duct
Na+ and H+ are exchanged w/ Na+ flowing into duct lumen and H+ flowing into blood
What is the function of alpha cells?
Pancreatic islet cells
Fine cytoplasmic granules
Forms glucagon
What is the function of beta cells?
Pancreatic islet cells
Coarse cytoplasmic granules
Produce insulin
What is the function of delta cells?
Pancreatic islet cells
Secrete somatostatin
Helps control insulin and glucagon levels
What cell types are within the islet of langerhan?
Alpha and Beta cells
Alpha - glucagon; fine granules
Beta - insulin; coarse granules
