3-stomach Flashcards
is the stomach essential for life
no, but yes for a good quality of life
what are the regions of the stomach
fundus, body, antrum
what is the fundus
top of stomach
what is the body of stomach
middle of stomach
what is the antrum
bottom of stomach
what does pepsinogen do
converted to pepsin, helps digest proteins
what do chief cells secrete
pepsinogen
where are chief cells
all regions of stomach
what is released by G cells
gastrin
where are gastric glands
antrum
how does gastrin work
stimulates HCl production by parietal cell and GI motility
what do ECL cells release
histamine
where are ECL cells
all stomach areas, more so in the antrum
what do d cells release
somatostatin
what does somatostatin do
negative regulator of HCl secretion
where are d cells
everywhere in stomach, more in antrum
what does intrinsic factor do
critical for B12 absorption in the ileum
where is HCl produced
fundus and body
where is mucous, pepsinogen and HCl released
fundus and body
where is mucous, pepsinogen and gastrin released
antrum
what is the fundus and body made from
thin layer of smooth muscle
what is the antum made of
thick smooth much
what does histamine do
stimulates HCl production
what do parietal cells do
secrete HCl and IF
what are canaliculus and where found
in parietal cell, they increase surface area to maximize secretion
which direction does the K+/H+ pump in parietal cell
H+ into lumen, K+ into cell, actively
how is carbonic anhydrase made in stomach
formed from H2O and CO2
what does H2CO3 dissociate into parietal cells
H+ (for secreion) and HCO3- (exchanged with cl-)
what kind of transport is the Cl-/HCO3- exchanger parietal cells
2 active
which direction does the Cl-/HCO3- exchanger go parietal cells
HCO3- out Cl- in
what happens to Cl- in the parietal cell
comes in from Cl-/HCO3- exchanger
leaves in leak channel
what happens to K+ in parietal cells
comes in from K/H+ pump
leaves in leak channel
what happens to HCO3- in parietal cells
leaves into blood, causes alkaline tide
what happens do H+ in parietal cells
leaves into lumen, makes it acidic
what is the cephalic phase of gastric secretion
excitatory, through vagus
what is the gastric phase of gastric secretion
major excitatory phase, gastrin
what is the intestinal phase of gastric secretion
inhibitory when fat, acid, hypertonic digestion products are in duodenum
what does ACh do to D cells
inhibit release of somatostatin
what does somatostatin do to parietal cells
inhibit H+ release
what does somatostatin do to ECL cells
inhibit histamine release
what does somatostatin do to G cells
inhibit gastrin release
what does ACh do to G cells
activate gastrin release
what does peptides do to G cells
activate gastrin release
what does H+ do to D cells
activate somatostatin release
what does H+ do to G cells
inhibit gastrin release
what does gastrin do to ECL cells
activate histamine release
what does ACh do to ECL cells
activate histamine release
where is the pyloric sphincter
at bottom/antrum
what do stomach pacemaker cells do
presets the frequency of contractions
what closes off in vomiting
glottis
what is damaged in ulcers
mucosa (top)
