gastrointestinal hormones

Question 1

what blood flow is gastrin secreted into ?

Answer 1

portal vein blood

Question 2

what are the two gastrin molecules ?

Answer 2

little gastrin
big gastrin

Question 3

where are the g cells ?

Answer 3

mucosal layer of the antrum

Question 4

where are parietal cells found ?

Answer 4

in the body of the stomach

Question 5

what are the three functions of gastrin ?

Answer 5

stimulation of parietal cells to secrete hydrogen
increase gastric motility
growth of gastric mucosa

Question 6

what are the stimuli of gastrin release ?

Answer 6

stomach distention
alkalinization
amino acids ( phenylalanine , tryptophan )
vagal stimulation through GRP

Question 7

what is gastrin inhibited by ?

Answer 7

low pH, somatostatin

Question 8

what is a gastrinoma ?

Answer 8

causes the zollinger ellison syndroome
occurs in the duodenum and in the pancreas
excessive acid secretion
hypertrophy and hyperplasia of the stomach mucosa

Question 9

what are the symptoms of a gastrinoma ?

Answer 9

abdominal pain that increases with food
chronic diarrhea - steatorrhea
ulcers in the distal duodenum
GERD

Question 10

what is special about the ulcers in zollinger ellison syndrome ?

Answer 10

refractory to PPI therapy
in the distal duodenum

Question 11

how is gastrinoma diagnosed ?

Answer 11

fasting levels of gastrin levels
secretin test

Question 12

what is secretin ?

Answer 12

hormone released by the duodenum in response to too much acid
1- inhibits gastrin release
2- stimulates bicarb secretion

Question 13

how does a secretin test work in a patient with a gastrinoma ?

Answer 13

normally secretin would decrease gastrin levels
but in a gastrinoma the secretin will increase gastrin levels due to abnormal G cells

Question 14

what are the treatment options for gastrinoma ?

Answer 14

high dose of PPI
octeotride ( somatostatin analogue)
surgical excision

Question 15

what is pernicious anemia and what are the associated findings ?

Answer 15

associated with autoimmune gastritis due to destruction of the parietal cells and hence a loss of intrinsic factor leading to B12 deficiency
g cell hyperplasia
megalobalstic anemia
high levels of gastrin

Question 16

what are the effects of cholecystokinin ?

Answer 16

gall bladder contraction
allows for release of pancreatic enzymes
decreases gastric emptying
allows for relaxation of the sphincter of oddi

Question 17

what cell is responsible for the release of cholecystokinin ?

Answer 17

I cells

Question 18

how dos cholecystokinin allow for the release of pancreatic enzymes ?

Answer 18

CCK receptors on the vagus nerve
releases Ach which works on the pancreas

Question 19

what are the stimuli for cholecystokinin ?

Answer 19

fatty acids and monoglycerides
amino acids and proteins

Question 20

when is CCk used for diagnostic purposes ?

Answer 20

in a HIDA scan , to test and evaluate RUQ pain

Question 21

what cells release secretin ?

Answer 21

s cells of the duodenum

Question 22

what is the action of secretin ?

Answer 22

1- increases pancreatic HCO3 secretion from pancreatic ductal cells
2- decreases acid secretion by inhibiting gastrin
3- increases bile secretion
promotes pancreatic flow

Question 23

what is the action of somatostatin ?

Answer 23

decreases kol 7aga

Question 24

what are the major stimuli for somatostatin ?

Answer 24

increasing acid production - low pH

Question 25

what is octeotride and what is the main use for it ?

Answer 25

somatostatin analogue used for bleeding varicies

Question 26

what are the other uses for octeotride ?

Answer 26

carcinoid tumor acromegaly gastrinoma/glucagonoma

Question 27

what is the function of GIP ?

Answer 27

glucose dependent insulinotropic peptide stimulates insulin release from the pancreas decreases hydrogen ion release

Question 28

what cells release GIP ?

Answer 28

k cells

Question 29

what is the only hormone that is release by all types of foods ?

Answer 29

GIP from k cells

Question 30

why is oral glucose metabolized faster than IV glucose ?

Answer 30

GIP IV glucose does not trigger GIP

Question 31

what is vasoactive intestinal peptide and where is it synthesized ?

Answer 31

synthesized by parasympathetic ganglia causes relaxation of the LES ,and mainly smooth muscles increases intestinal water and electrolytes secretion raises pH - inhibit gastric H

Question 32

what are the symptoms of VIPoma ?

Answer 32

rare tumor of the islet cells watery diarrhea hypokalemia achlorydia

Question 33

what is special about the diarrhea associated with VIPoma ?

Answer 33

tea coloured odorless watery diarrhea resembles cholera

Question 34

other name for VIPoma ?

Answer 34

pancreatic cholera syndrome WDHA syndrome

Question 35

what is the typical case associated with VIPoma ?

Answer 35

adult long standing watery diarrhea no response to diet change

Question 36

what is the treatment for VIPoma ?

Answer 36

fluid/electrolyte replacement octreotide

Question 37

where is motilin secreted from and what is its function ?

Answer 37

promotes motility in the fasting state released by kolo

Question 38

when are the highest levels of motilin found ?

Answer 38

in between meals when you are not eating

Question 39

what drug is used to treat gastroparesis ?

Answer 39

erythromycin - as it binds to motilin receptors

Question 40

what are the digestive phases ?

Answer 40

cephalic phase - just thinking about food - allows for vagus stimulation gastric phase - consume food intestinal phase