Lecture 40 11/27/23 Flashcards
Which functions of hormones/secretions in the duodenum and jejunum are associated with providing time for present food to process?
-decreased appetite
-inhibition of gastric acid secretion
-slowing of gastric emptying
Which functions of hormones/secretions in the duodenum and jejunum are associated with optimizing digestion?
-releasing bicarbonate to neutralize acidic chyme
-stimulating digestive enzyme secretion
-stimulating bile acid secretion
What are the stimuli for secretin production?
-low duodenal pH
-intraduodenal nutrients
What are the actions of secretin?
-inhibit acid secretion
-slow gastric emptying
-stimulate HCO3-rich pancreatic fluid secretion
Which enzyme is involved in sodium-bicarbonate buffering of hydrochloric acid?
carbonic anhydrase
What are the stimuli for cholecystokinin (CCK)?
-intraduodenal nutrients
-H+ ions
What are the actions of CCK?
-inhibit gastric emptying
-increase secretin secretion
-increase pancreatic enzyme secretion
-stimulate pancreatic growth
-cause gall bladder to contract
-relax sphincter of Oddi in the gall bladder
What is the stimulus of gastric inhibitory peptide?
intraduodenal nutrients
What are the actions of gastric inhibitory peptide?
-inhibition of gastric acid secretion
-stimulation of pancreatic insulin release when blood sugar is high (incretin)
What is an incretin?
a substance that increases insulin release
Which type of pancreas makes up the majority of the pancreas?
exocrine
How is the exocrine pancreas arranged?
into acini and ducts
What are the characteristics of pancreatic enzyme secretion?
-secreted by acinar cells
-stimulated by CCK and acetylcholine
What are the characteristics of bicarbonate-rich fluid secretion?
-secreted by ductal cells
-stimulated by secretin
What are zymogens?
the precursor molecules of protein-digesting enzymes
Why are protein-digesting enzymes produced as zymogens first, instead of in their active form?
active form could break down pancreatic tissue
Where are zymogens activated into protein-digesting enzymes?
duodenal lumen
What are the characteristics of trypsinogen?
-activated into trypsin
-activated by enterokinase
-trypsin activates the other protein-digesting enzymes