Fan - Exopancreatic, Intestinal, And Hepatic Secretions Flashcards
What is the process of activating pancreatic zymogens
Trypsinogen is converted to trypsin in the duodenum By a brush border enzyme called enterokinase. Trypsin then converts the pancreatic zymogens into their active forms
What are some examples of pancreatic zymogens enzymes being activated at the wrong time? What would occur?
Pancreatitis would occur.
If there were some sort of trauma to the abdomen, trypsin would be activated by proteases released from the injured pancreatic cells.
Also if there were congenital trypsin inhibitor deficiency.
What is the general pH of pancreatic juice? Why?
High (alkaline), because pancreatic juice has a lot of HCO3- in it, which sops up all of the H+ ions.
What ions are in high concentration in pancreatic juice and which are in low concentrations?
High - HCO3- and Na
Low - Cl- and K+
why are HCO3- and Cl- inversely proportional in the pancreatic juice?
Because they share a cotransporter than brings in Cl- while secreting HCO3- into the lumen.
WHat is the action of secretin on the Pancreatic juice? WHat potentiates this?
Secretin stimulates CFTR to secrete CL- into the lumen. It is potentiated by CCK and Ach enhancing the K+ channel to dump K+ into the serosal side and thus making the cell more negative.
How is. The CFTR channel regulated?
Proton will activate secretin, which will cause adenylate cyclase to convert ATP–>cAMP and then PKA will phosphorylate CFTR to activate it.
How do toxins affect the CFTR channel?
It will cause constitutive activation of adenylyl cyclase so the CFTR channel will always be open.
WHat occurs in the Tip of the intestinal crypt? What happens in the base?
Tip - Na is brought In first and then Chloride follows. Water follows the ions into the intestinal crypt.
Base - Chloride is kicked out first and then Sodium follows, which brings water with it back out into the lumen.
How do we treat the patient who is having diarrhea due to a endotoxin?
There is a glucose/Na transporter called SGLT. If we hyperactivate this transporter then we will have excessive glucose ad sodium reabsorption which will cause Cl- and water to follow. How do we do this? Give them Glucose and Sodium in the same concentrations.
When does most of the primary bile salt synthesis take place? When is it best for a ileal resection patient to have a fatty meal?
AT night time, therefore it is best if they have a fatty meal in the morning because they have their freshly synthesized primary bile acids. Remember, without an ileum, there is no reabsorption of secondary bile acids andd no negative feedback.
Dumping syndrome
When Ingested food passes through the stomach very rapidly. There is a sudden increase in osmotic pressure generated by digestive enzymes pulling water into the GI lumen. There is also fermentation of these nutrients by the colonic bacteria. Patient will have a loss of blood volume to the GI tract so they will be tachycardic and weak. Patient will have watery, painless diarrhea with gas. Common in gastric bypass patients.
