GI phys 2
Medicine Module 3 with Edmonson at Medical College of Georgia
About this deck
By: R. C.
Created: 2011-01-05
Size: 30 flashcards
Views: 2
Created: 2011-01-05
Size: 30 flashcards
Views: 2
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stomach
storage reservoir
intrinsic factor secretion
chemical and enzymatic digestion of proteins, others
kill bacteria
slow release of chyme into SI
intrinsic factor secretion
chemical and enzymatic digestion of proteins, others
kill bacteria
slow release of chyme into SI
gastric
fundus and body of stomach
HCl, pepsinogen, IF, mucus, renin/chymosin
HCl, pepsinogen, IF, mucus, renin/chymosin
pyloric
antrum of stomach
gastrin, mucus, small amts pepsinogen
gastrin, mucus, small amts pepsinogen
gastric
3 cell types
mucus neck cells
chief cells: pepsinogen, renin
parietal: HCl, intrinsic factor
mucus neck cells
chief cells: pepsinogen, renin
parietal: HCl, intrinsic factor
gastric acid
kill germs
convert pepsinogen to pepsin
begin protein digestion with pepsin
pepsin functions at pH 1.8-3.5
convert pepsinogen to pepsin
begin protein digestion with pepsin
pepsin functions at pH 1.8-3.5
gastric juice
HCL converts pepsinogen to pepsin
pepsin: protein digestion
mucus: protective coating for stomach
intrinsic factor: binds b12 for absorption in ileum
pepsin: protein digestion
mucus: protective coating for stomach
intrinsic factor: binds b12 for absorption in ileum
mucous neck cells
maintain surface of stomach near pH 7
soluble mucus: vagal stimulation
surface: secrete viscous mucus, released in response to chemical or physical irritation
intrinsic factor - parietal cells-binds b12
soluble mucus: vagal stimulation
surface: secrete viscous mucus, released in response to chemical or physical irritation
intrinsic factor - parietal cells-binds b12
proximal 80% stomach
HCL and requires energy in the form of ATP
intrinsic factor
stomach: dietary b12 bound by IF in gastric juice
ileum: IF-b12 complex is absorbed, IF binds to its receptor
without IF, 1/50th of b12 is absorbed
very important for maturation of RBCs
ileum: IF-b12 complex is absorbed, IF binds to its receptor
without IF, 1/50th of b12 is absorbed
very important for maturation of RBCs
gastric secretion
chief cells: secrete pepsinogen, conversion at pH <5, at pH 2 is instantaneous
pepsinogen
inactive secreted form of pepsin
proteolytic enzyme
reversibly inactivated at pH>5, irreversible at pH>7-8
vagal stimulation via ACh and direct response to gastric acid stimulate secretion
proteolytic enzyme
reversibly inactivated at pH>5, irreversible at pH>7-8
vagal stimulation via ACh and direct response to gastric acid stimulate secretion
rennin
proteolytic enzyme: causes milk to curdle in stomach
maximal first few days after birth, replaced by secretion of pepsin as major gastric protease
secreted as inactive proenzyme (prochymosin), activated w acid
maximal first few days after birth, replaced by secretion of pepsin as major gastric protease
secreted as inactive proenzyme (prochymosin), activated w acid
pyloric glands
g cells secrete gastrin
mucus neck cells secrete mucus for lubrication and protection
oxyntic/parietal cell: h/k atpase
mucus neck cells secrete mucus for lubrication and protection
oxyntic/parietal cell: h/k atpase
+ regulation of gastrin
gastrin releasing peptide: stimulates gastrin release from g cells
small peptides and aas: directly stimulate gastrin release from g cells
small peptides and aas: directly stimulate gastrin release from g cells
- regulation of gastrin
somatostatin: inhibits release from g cells
antrum acidification: pH <3 inhibits release
antrum acidification: pH <3 inhibits release
histamine regulation
gastrin and ACh stimulate histamine release from ECL cells
specialized endocrine cell in gastric mucosa
proliferation of ECL cells in hypergastrinemic states: gastrin-secreting tumors
specialized endocrine cell in gastric mucosa
proliferation of ECL cells in hypergastrinemic states: gastrin-secreting tumors
ECL regulation
gastrin and ACH regulate histamine from ECL
Parietal regulation
HCL secretion regulated by histamine, gastrin, and ACh
cephalic
HCL and pepsinogen
seeing, smelling, anticipating food. brain tells stomach to prepare for meal
20% of acid response
mechano/chemo r's, central pathway/thought, hypoglycemia
Blocked by vagotomy
afferent: vagus to brain
efferent: vagus to stomach
parietal cells secrete HCL
chief cells secrete pepsinogen
seeing, smelling, anticipating food. brain tells stomach to prepare for meal
20% of acid response
mechano/chemo r's, central pathway/thought, hypoglycemia
Blocked by vagotomy
afferent: vagus to brain
efferent: vagus to stomach
parietal cells secrete HCL
chief cells secrete pepsinogen
gastric
when meal enters stomach: 70% of acid response to meal
stimuli: increased pH, distension (local and vagovagal), peptides, aas, ca, alcohol/wine, caffeine, coffee
afferent: enteric and vagus to brain
efferent: enteric and vagus to stomach
parietal: hcl secretion
chief: pepsinogen
g cells: gastrin secretion
stimuli: increased pH, distension (local and vagovagal), peptides, aas, ca, alcohol/wine, caffeine, coffee
afferent: enteric and vagus to brain
efferent: enteric and vagus to stomach
parietal: hcl secretion
chief: pepsinogen
g cells: gastrin secretion
intestinal
chyme pH >3
stimulus: chyme in duodenum-mechanor's and chemo r's, enteric nerves, result in secretion of some gastric juice from stomach
stimulus: chyme in duodenum-mechanor's and chemo r's, enteric nerves, result in secretion of some gastric juice from stomach
brunner's glands
first part of duodenum
mucus: protects duodenum from chyme
crypts of lieberkuhn: in SI, serous: watery fluid similar to extracellular fluid
mucus: protects duodenum from chyme
crypts of lieberkuhn: in SI, serous: watery fluid similar to extracellular fluid
LI
crypts of lieberkuhn but no villi or enzymes
alkaline mucus
mucus secretion increased by PNS stimulation
protection of wall against excoriation, hold fecal matter together, protect intestinal wall from bacteria
alkaline mucus
mucus secretion increased by PNS stimulation
protection of wall against excoriation, hold fecal matter together, protect intestinal wall from bacteria
biliary system
liver, gallbladder, bile duct, duodenum, ileum, portal circulation
need bile salts to make insoluble lipids more hydrophilic with OH
emulsification of fat globule by bile salt
need bile salts to make insoluble lipids more hydrophilic with OH
emulsification of fat globule by bile salt
pancreas
chyme floods into SI
acid neutralized to prevent damage to duodenal mucosa
proteins, fats, starch broken down
digestive enzymes for all food types
hco3 for neutralizing acid chyme
aqueous: h2o and hco3, by cells lining pancreatic ducts
enzymes, lipase, amylase
endocrine: insulin, glucagon
exocrine: digestion
acid neutralized to prevent damage to duodenal mucosa
proteins, fats, starch broken down
digestive enzymes for all food types
hco3 for neutralizing acid chyme
aqueous: h2o and hco3, by cells lining pancreatic ducts
enzymes, lipase, amylase
endocrine: insulin, glucagon
exocrine: digestion
pancreatic enzymes
stored in zymogen granules
proteolytic: protein to aas
pancreatic lipase: fat to FAs
amylase: CHO to disaccharides
controlled by CCK
inactive, activated when they reach SI
proteolytic: protein to aas
pancreatic lipase: fat to FAs
amylase: CHO to disaccharides
controlled by CCK
inactive, activated when they reach SI
regulation of pancreas
H and fats increase secretin in SI
fats and aas increase CCK in SI
secretin increases fluid and hco3
CCK increases enzyme secretion
nerve increases enzyme secretion
fats and aas increase CCK in SI
secretin increases fluid and hco3
CCK increases enzyme secretion
nerve increases enzyme secretion
hco3
neutralizes acid chyme
creates optimal pH 7-8 for digestive enzymes
amylase, lipase, proteases
na, cl, k, hco3
creates optimal pH 7-8 for digestive enzymes
amylase, lipase, proteases
na, cl, k, hco3
acid entering duodenum
regulates fluid and hco3 secretion
secretin - acid
secretin - acid
fat and protein entering duodenum
regulates secretion of enzymes
ACh - vagovagal reflexes
CCK - fat and protein
ACh - vagovagal reflexes
CCK - fat and protein
About this deck
By: R. C.
Created: 2011-01-05
Size: 30 flashcards
Views: 2
Created: 2011-01-05
Size: 30 flashcards
Views: 2
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“Simply amazing. The flash cards are smooth, there are many different types of studying tools, and there is a great search engine. I praise you on the awesomeness.”
Dennis
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