L7 - Small Intestinal Phase Flashcards
Presence of fat, H+, and hyper osmotic content in duodenum promotes…
inhibition (slowing) of gastric emptying via 1. CCK 2. CNX efferents decrease motility, contract pylorus 3. H+ receptor mediated Myenteric plexus relax gastric smooth muscle
Which of the following make HCO3-? A. Exocrine pancreas B. Biliary ductules C. Duodenal epithelial cells D. All of the above
D. all of the above
The majority of pancreatic volume is exocrine, or endocrine?
Exocrine 90%
Which of the following cells of exocrine pancreas secrete enzymes? A. Acinar cells B. Centroacinar cells C. Ductal cells D. B and C
A. Acinar cells. Centroacinar cells and ductal cells secrete the aqueous component.
Pancreatic exocrine acinar fluid production is regulated by
CCK
Pancreatic exocrine ductal fluid production is regulated by
Secretin
What triggers secretin release from S-cells (in duodenum), to promote ductal bicarbonate secretion in the pancreatic TUBULAR cells?
low pH
Secretin-mediated cAMP directly stimulates which transporter, in pancreatic ductal cells? A. NHE-1 B. NBC-1 C. Bicarb/Cl- antiporter D. CFTR
D. CFTR
CFTR-mediated secretion of Cl- powers the secretion of
HCO3- via the Cl-/HCO3- antiporter on the luminal ductal cell of pancreas. This antiporter is coupled with CFTR.
CFTR “couples with” what transporter, on the luminal side of pancreatic ductal cells?
Cl-/HCO3- antiporter
Name 2 sources of secreted HCO3-, via the Cl-/HCO3- antiporter on luminal side of pancreatic ductal cell.
From within: Carbonic anhydrase From without: Na/Bicarb symporter (NBC-1)
In Cystic fibrosis A. Secretin release by I-cells is impaired B. CFTR is impaired C. Acinar cells don’t release enzymes D. Bicarb secretion is intact
B. CFTR is impaired
CCK is released from what cells?
I-cells in duodenum
I-cells can DIRECTLY interact with which of the following, to promote secretion of CCK? A. Fatty acids & Proteins B. CCK releasing peptide C. Monitor peptide D. All of the above
D. All of the above
What stimulates pancreatic release of monitor peptide?
CN X Enteric nervous system
What digests monitor peptide and CCK-RP?
Trypsin
What competes with monitor peptide and CCK-RP, for Trypsin-digestion?
Protein rich meal. In effect, dietary proteins free up CCK-RP and monitor peptide, which are now available to promote release of CCK from I-cells, so that CCK can stimulate release of digestive enzymes from pancreatic acinar cells for that meal. When you’re NOT eating, you don’t need CCK, and trypsin is free to digest CCK-RP and monitor peptide.
Which does not promote intracellular Ca++ levels in pancreatic acinar cells? A. VIP B. GRP C. CCK D. GRP
A. VIP
What hormone relaxes the Sphincter of Oddi?
CCK
What hormone promotes contraction of gallbladder?
CCK
What is the major constituent of bile?
Bile acid (65%)
How are conjugated bile acids re-absorbe into enterohepatic circulation?
ASBT (apical Na+ dependent bile acide transporter) in terminal ileum
If bile acid is conjugated, then
it cannot passively cross the intestinal epithelial lining
What type of contraction occurs in the esophagus, pharynx, gastric antrum, small/large intestine?
Peristaltic
