Phys: Gallbladder Pancreas Flashcards
What controls the relaxation of the Sphincter of Oddi?
CCK
What forms the Ampulla of Vater?
Pancreatic duct and common bile duct
What cells of the pancreas secrete digestive enzymes?
Acinar cells
What duodenal enzyme activates pancreatic enzymes?
Enteropeptidase
What do centroacinar and duct cells do to the enzymes produced by acinar cells?
Dilute them and make them rich in sodium and bicarbonate!
What is the target of enteropeptidase?
Trypsinogen
What is triggering activation of acinar cells during cephalic and gastric phases?
Parasympathetics via dorsal motor nucleus of vagus…release of acetylcholine on muscarinic receptors of acinus
During what phase is most of the pancreatic enzyme release happening?
Intestinal phase
What cells release CCK?
I cells
H+ ions cause S cells to release what during the ___________phase.
Secretin
Intestinal
What does secretin do?
Activates pancreatic duct cells to secrete bicarbonate
Where are the CCK receptors?
Acinar cells…trigger further fusion of zymogens
What triggers CCK-RP release from pancreas?
Amino acids
Fatty acids
What does CCK increase the release of in the pancreas?
Monitor peptide and pancreatic enzymes
What do pancreatic enzymes do to CCK and Monitor protein?
Digest them! Turning off CCK secretion
What does CCK do to gall bladder?
Contraction
Where does enteropeptidase come from?
Brush border of Duodenum
Hereditary pancreatitis occurs due to a mutation in the trypsinogen PRSS1 gene causes activation of digestive enzymes in the pancreas which can lead to inflammation…..Autosomal dominant or recessive?
Dominant!
Alteration of one allele is enough to change the phenotype
What does the duodenal pH need to be in order to secrete secretin?
(I can’t think of it at the moment) but its acidic :/
Ooooo! Its
Do you predict a patient on a proton pump inhibitor will have increased or decreased duodenal bicarbonate secretion posprandially?
Decreased!
There won’t be an acid signal to induce secretin release
What does secretin do?!
Initiates secretion of bicarbonate solution by pancreatic duct cells!
What second messenger does secretin operate through?
cAMP
What second messenger does CCK operate through?
Ca++
Where was the alkaline tide generated? (organ)
Stomach
What would be a consequence on bicarbonate secretion in a pancreas with cystic fibrosis?
Decreased bicarbonate
**Pancreatic insufficiency–90 % reduction in amount of enzymes reaching intestine
What can alcohol do to acinar cells?
Hyperstimulate them…premature activation of trypsin…this can lead to cell death
Why would you see malabsorption of fat with pancreatitis?
Because we aren’t going to have sufficient colipase and lipase in the duodenum…won’t be able to cleave TAG to have fatty acids packaged into micelles to be absorbed!
What part of the brain is important in regulating energy homeostasis?
Hypothalamus
What cells release GLP-1? *Glucagon-like peptide
L cells
What cells release GIP? *Glucose-dependent insulinotropic peptide
K cells
What does GLP-1 do to levels of insulin and glucagon?
Increases insulin, decreases glucagon
What are the positive regulators of insulin secretion?
GLP-1
Amino acids
CCK
ACh
What are the inhibitors of Insulin secretion?
Somatostatin
NE
What things act as satiety signals to decrease food intake and increase energy expenditure?
Act at hypothalamus
GLP1
CCK
Insulin
Leptin
If someone has low Leptin, what would you expect?
Don’t get satiety signal…always eating! Likely obese
What peptide hormone stimulates appetite? Where is it produced?
Ghrelin
Fundus of stomach
What peptides are involved in the Ghrelin pathway?
Neuropeptide Y
Agouti-related peptide
What cells of the pancreas does gastrin activate during cephalic/gastric phases?
Acinar cells
Name some of the cool stuff our liver does! 5 general categories
Detoxifies drugs & bacteria
Metabolizes carbs, fat, protein
Stores glycogen, fat, V B12, A, K
Synthesizes good stuff for our circulatory system
Makes bile! Enables lipid uptake and excretion of lipophilic molecules
Why is there a lot of Smooth ER in the liver?
Because it makes cholesterol!
Hepatic triad
Portal vein
Hepatic artery
Common bile duct (reverse direction of the other 2)
How does blood leave the liver?
Via central vein…enters IVC
Major workforce cell of liver
Hepatocyte
What type of cells are Kupffer cells?
Macrophage
What enters the Space of Disse?
Sieving by RBCs to allow passage of chylomicron remnants into this space!
What do stellate cells do?
Produce collagen and store lipids like Vitamin A
What causes Jaundice?
Unconjugated bilirubin
Cirrhosis
Hardening of liver due to irreversible deposition of excess collagen
Describe the pathology of liver cirrhosis
Oxidative stress causes Kupffer cells to release cytokines inducing collagen production by stellate cells. Accumulation of collagen increases resistance to blood flow (portal hypertension) and reduced hepatic function (hepatic encephalopathy)
What cells make bile?
Hepatocytes
What is bilirubin conjugated to to promote excretion?
Glucuronic acid (via glucoronidase)
Sx of unconjugated bilirubin build up
Abdominal pain
Pruritis
Jaundice
Yellow pigment in urine
Urobilin
Green color of bile
Conjugated bilirubin
Yellow contributing to jaundice
Unconjugated bilirubin
Brown color in poop
Stercobilin
Amphipathic
Which molecules are amphipathic?
Hydrophobic on one side.
Hydrophilic on the other side.
Helps make it soluble in aqueous environment
*Primary bile acids
What amino acids can bile acids be conjugated to to generate bile salts?
Glycine
Taurine
Reabsorbed bile acids exert a negative feedback on what enzyme so you aren’t synthesizing as many bile acids?
7-alpha hydroxylase
What does bile acid sequestrant (cholestyramine) do to serum cholesterol levels?
Decrease because more cholesterol is being diverted to produce bile acids
Why are glucose and amino acids reabsorbed from bile in the cholangiocytes of the canals of Hering?
To prevent bacteria overgrowth that could lead to deconjugation
What transporter uptakes conjugated bile acids in the lieum?
sodium-dependent bile salt transporter (ASBT) through secondary active transport!
What transporter transports bile acids to portal circulation?
Organic solute transporter (OST)
Cholestasis
Impaired bile secretion…creates a higher risk of forming stones
What hormone reduces gallbladder smooth muscle tone?
Progesterone (makes it more likely for things to precipitate because it can’t contract as good!)
2 types of cholelithiasis
cholesterol (most common)
Pigment stones
Tx for cholesterol stones
increase bile acids–to promote solubilization of cholesterol
Why might you have a bleeding disorder associated with gall stone blockage?
Decreased vitamin K absorption
Explain the CCK regulation stuff
Monitor peptide is released during cephalic and gastric phases from the pancreas
CCK-RP is released from the pancreas in intestinal phase
When monitor peptide and CCK-RP hook up, they cause the release of CCK from I cells into the blood!
CCK increases the release of monitor peptide and other pancreatic enzymes.
Pancreatic enzymes digest luminal nutrients, CCK-RP and monitor peptide to turn of CCK secretion
Who is the master regulator of the duodenal cluster unit?
CCK!!!
What does CCK do to gallbladder, pancreas, stomach, sphincter of oddi, brain?
Gallbladder: contraction Pancreas: increase acinar secretion Stomach: Reduce emptying Sphincter of Oddi: relax Brain: decrease food intake
What happens if someone has a PRSS1 gene mutation?
Hereditary pancreatitis…trypsinogen gene mutation that causes activation of enzymes IN THE PANCREAS rather than the duodenum….serious inflammation
How can alcohol cause pancreatitis?
Can be metabolized into products that cause hyperstimulation of acinar cells –> Intracellular trypsin activation prematurely–>cell death!
Why is pancreatic exocrine activity highest in intestinal phase?
Due to secretion of CCK and secretin!
Where is CCK released from?
Duodenum (I cells)
Why may a baby be jaundiced?
Delayed expression of Glucoronidase!! Can’t conjugate bilirubin to glucoronic acid
What is added to bile in the canals of Herring?
IgA and mucus
What opens the Sphincter of Oddi?
CCK (I know I’ve over done this…but you should know it!)
Cause of cholesterol stones?2
Too much cholesterol
Too little bile
How can ZE syndrome cause steatorrhea?
H+ makes lipase not as active…poop out the fat!
