Peptidergic regulation of the GIT

Question 1

Define endocrine, paracrine and neurocrine

Answer 1

endocrine - cells release hormone into the blood for far target
paracrine - messenger into ecf for neighbouring effect - immediate
neuroncrine - sensory - inter - motor - neurotransmitter released for acute effect

Question 2

what is the source, stimulus, pathway and target of gastrin in the stomach

Answer 2

Released from g cells
stimulated by neural input, aa or peptides in the stomach
endocrine pathway
targets ecl and parietal cells

Question 3

what is the source, stimulus, pathway and target of CCK

Answer 3

released from I cells in the duodenum
stimulated by ffa and some aa
paracrine and endocrine
targets vagal afferents and pancreatic acing cells

Question 4

what is the source, stimulus, pathway and target of secretin

Answer 4

S cells in the duodenum
stimulated bu acid in then small intestine
endocrine and paracrine
vagal afferent and pancreatic duct cells

Question 5

what is the source, stimulus, pathway and target of motilin

Answer 5

Intestine
neural input or fasting
paracine
upper GI motility

Question 6

what is the source, stimulus, pathway and target of Gastric inhibitory peptide (GIP)

Answer 6

k cells in the intestine
fatty acids, glucose and aa in the small intestine
endocrine
B cells in the pancreas

Question 7

what is the source, stimulus, pathway and target of GLP-1

Answer 7

L cells in the intestine
carbs and ffa
endocrine and paracrine
endocrine pancreas

Question 8

what is the source, pathway and target of vasoactive intestinal peptide throughout the intestine

Answer 8

nerve terminals
neurocine
secretory cells

Question 9

what are peptides released from and from where

Answer 9

APUD

amine precursor uptake decarboxylation cells on epithelial cells of the git

Question 10

what do mucus neck cells secrete

Answer 10

mucus and bicarbonate

Question 11

what do parietal cells secrete

Answer 11

HCL and intrinsic factor

Question 12

what do ECL cells secrete

Answer 12

histamine

Question 13

what do chief cells secrete

Answer 13

pepsinogen

gastric lipase

Question 14

what do d cells secrete

Answer 14

somatostatin

Question 15

what do g cells secrete

Answer 15

gastrin

Question 16

where are g cells located

Answer 16

in the bottom of crypts in the antrum and duodenum

Question 17

what are the two effects of gastrin

Answer 17

stimulate both ecl and parietal cells

increases mucosal growth

Question 18

what is the cephalic reflex and what kind of mechanism is it

Answer 18

feedforward mechanism

sight or small of food induces vagal input to g cells to simulate gastrin release

Question 19

what happens to gastrin release when food reaches the stomach and why

Answer 19

food hits the stomach and peptides and aa present stimulate more gastrin release

Question 20

what does histamine do

Answer 20

stimulates parietal cells to release more hcl

Question 21

what does a high acid conc in the stomach do to chief cells

Answer 21

triggers chief cells to release pepsinogen which gets metabolised to pepsin which hydrolyses proteins to aa which further releases gastrin

Question 22

describe the negative feedback when acid conc is high in the stomach

Answer 22

low ph stimulates d cells to release somatostatin which inhibits g cells, ecl cells and parietal cells

Question 23

how is gastrin inhibited

Answer 23

d cells
reduced cephalic reflex
reduced neural input

Question 24

what is zollinger ellison syndrome

Answer 24

tumour of the pancreas which stimulates g cells in the stomach to secrete more gastrin

Question 25

what is a gastrinoma

Answer 25

tumour of g cells in the stomach hyper secretion of gastrin

Question 26

how could you test for ellison zollinger syndrome

Answer 26

give them secretin and if theres no change in acid levels then there is a gastronoma or tumour of the pancreas causing stimulation of g cells

Question 27

what are the symptoms of elision zolinger syndrome

Answer 27

peptic ulcer causing bleeding diarrhoea heart burn low potassium and calcium levels

Question 28

how would you treat EZS

Answer 28

remove the tumour via surgery | use proton pump inhibitors

Question 29

what does secretin do in EZS

Answer 29

increase bicarbonate concentration via increases in bile fluids and pancreatic fluids to try and neutralise acid build up

Question 30

what do duodenal I cells do

Answer 30

secrete cck increasing bile production and decreases gastric secretions and motility also increases number of pancreatic cells

Question 31

what does vasoactive inhibitory peptide do (VIP)

Answer 31

released from nerve terminals in the gut causes dilation of smooth muscle increase in salivary gland blood flow increase in intestinal fluid

Question 32

what is verner morrison syndrome and what are the symptoms

Answer 32

excessive secretions low chloride and potassium levels excessive tropic effect of the pancreatic cells

Question 33

what is the treatment of verner morrison syndrome

Answer 33

removal of the tumour from the tail of the pancreas rebalance the electrolytes and fluids octreotide inhibitor