Littleton Part III Flashcards
Acid secretion is influenced by what?
pH, food buffering, and gastric emptying
What happens to food buffers during food ingestion and after eating?
During ingestion there is peak in food buffers in the stomach and hours after eating it decreases
What happens to the rate of hydrogen secretion during ingestion and after?
during ingestion it does not increase.
1 hour after ingestion it increases and then maxes out after 2 hours due to the release of somatostatin. Somatostatin causes it to decrease.
Don’t forget rate of H+ secretion is done by the parietal cells
What happens to the concentration of hydrogen ions during ingestion of food and after?
Hydrogen concetration decrease during ingestion of food. After two hours the concentration of Hydrogen ions increases and continues to increases.
When does the stomach have the lowest level of acid?
1-2 hours after a meal
Pancreatic secretions are stimulated by what?
Neural and humoral mechanism
The major stimulus for acini secretion is?
CCK (humoral)
acini cells have receptors for Ach (neural), M3, GRP (neural), and VIP (neural)
Acini cells secrete what?
digestive enzymes
What is the stimulus for pancreatic duct secretion?
Secretin (humoral)
What do pancreatic duct cells secrete?
Na HCO3, H20
Pancreatic duct cells have receptors for?
Ach (neural)
secretin (humoral)
In the duct lumen if you have a high rate of pancreatic juices what are your levels of bicarb and Cl-?
More bicarb
less chloride
In the duct lumen if you have a low rate of pancreatic juices what are your levels of bicarb and Cl-?
More Chloride
less bicarb
Are pancreatic secretions alkaline or acidic during the intestinal phase of the meal?
Alkaline
Secretion of bicarb increases and chloride secretion decreases. This causes a increase in pH.
(potassium unchanged)
Pancreatic acinar cells secrete many different proteins, what are there categories?
Proteases
Amyolytic enzyme
Lipases
Nucleases
and there is a others categories
Examples of proteases secreted by pancreatic acinar cells?
trypsinogen
chymotrypsinogen
proelastase
procarboxypeptidase A
procarboxypeptidase B
Examples of amyolytic enzymes?
amylase
Examples of lipases?
lipase
lipase-related proteins
prophospholipase A1, A2
nonspecific esterase
Examples of nucleases?
deoxyribonucleases
ribonucleases
What are the enzymes listed in the others catagories for enzymes secreted by the pancreatic acinar cells?
procolipase
trypsin inhibitors
monitor peptide
Contraction of the gallbladder and sphincter of oddi relaxation by both neural and humoral pathways is stimulated by what?
CCK
CCK is released by the small intestine -> vagal afferent seignal to DVC -> vagal efferent signal sent to gall bladder (acts on Ach) and sphincter of Oddi (act on VIP/NO)
In some people the common bile duct fuses with main pancreatic duct instead of sphincter of oddi. If you get a gallstone what can this lead to?
It prevents pancrease from releasing enzymes
Pancreatic polypeptide is a feedback modulator of _____ ________ to the pancrease
Vagal efferents
