Secretions Flashcards
salivary glands secrete what two products that are important for digestion?
amylase and lipase
what do ductal cells in the salivary glands take out of the mucous? what dot hey put in?
Na/Cl out
bicarb K+ in
if the mucous flows slowly through the ducts…does more or less NaCl go out?
more goes out with slow
more stays in with fast
what two stimuli increase secretion of mucous from salivary glands?
para and sympathetic
where are G cells located in the stomach? two locations
antrum and pylorus
what do G cells mainly secrete?
gastrin
where are D cells located in the stomach?
near G cells
what do G cells secrete? what is the function of this molecule?
somatostatin
it inhibits gastrin production from G cells
what are enterchromaffin cells…what do they secrete and what is the function of this molecule?
secrete histamine that promotes acid secretion
what three molecules increase acid release in stomach?
gastrin
histamine
ACh
how is acid pumped into the stomach
?
K/H+ antiport
how is H+ made in parietal cells?
carbonic anhydrase converts carbonic acid into H and HCO3
how does food affect the pH of the stomach?
raised the pH because it buffers the stomach acid
during the interdigestive phase…is the stomach pH low or high? why?
it is low…because the parietal cells are secreting basal level and there is no food to buffer the acid
what inhibits the stomach pH from getting way too low during interdigestive phases?
somatostatin release from delta cells in the stomach
what is the cephalic phase of gastric secretion? what nerve mediates this?
smell food…mediate by vagus nerve
what are the three targets of the vagus nerve during the cephalic phase in the stomach? and what do they cause release of at each location?
parietal cell-H+
GRP (G cell)-gastrin
chief cell-pepsinogen
if you use a muscarinic blocker during the cephalic phase…does the stomach acid still increase?
yes because the GRP is still stimulated…but the parietal cell and chief cell are not
in the gastric phase of gastric secretion…what three things does the vagus target and what does it cause to be released?
parietal cell-H+
GRP (G cell)-gastrin
chief cell-pepsinogen
in the gastric phase of gastric secretion…what does th enteric system cause? is this a short or long arc refelex?
short arc reflex using Ach to cause G cell to release gastrin
in the gastric phase of gastric secretion…what do peptides/amino acids stimulate?
G cells
in the intestinal phase of gastric secretion…what do partially digested proteins cause in the stomach?
activation of G cells and increased gastrin
what molecule stimulates pancreatic secretions?
CCk
what molecule potentiates pancreatic secretions?
ACh
in the pancreatic duct cells…what molecule stimulates them?
secretin
in the pancreatic duct cells…what molecule is held onto and what molecule is pumped into secretion?
Cl is held onto and bicarb is pumped out
what is CCKs effect on the stomach
delay gastric emptying
what is CCKs effect on the sphincter of oddi?
relax it
what is CCKs effect on pancreas?
increase enzyme secretion and gallbladder contraction
what two things stimulate CCK release from the SI?
amino acids and fatty acid
what two things stimulate secretin release from the SI?
low pH and fatty acids
what is secretins effect on the stomach? what molecule does it stimulate to achieve this?
it decreases the stomach acid production by increasing the amount of somatostatin
what is secretins effect on the pancreas/liver?
increases the release of bicarb from both
what are the main things that are secreted into chyme in the SI by the SI?
electrolytes and water
explain how the SI secretes water and electrolytes into the chyme…what are the main electrolytes
Cl is pumped through using cAMP and cholera toxins to induce its action…then Na and H20 follow Cl but follow it paracellularly
where does Cl move through to get into the lumen? what about Na and H2O
Cl moves through luminal surface of luminal cell
Na and H2O move paracellularly
what two molecules stimulate release of water and electrolytes in the SI?
ACh and VIP
name the five regulatory factor secretions of the SI
secretin CCK VIP GIP Gastrin motilin
