pharmacology

Question 1

What do mucus cells secrete?

Answer 1

mucus and bicarbonate

Question 2

what do parietal cells secrete?

Answer 2

hydrochloric acid

Question 3

what do enterochromaffin cells secrete?

Answer 3

histamine

Question 4

what do G cells secrete?

Answer 4

gastrin

Question 5

What do D cells secrete?

Answer 5

somatostatin

Question 6

What do chief cells secrete?

Answer 6

pepsinogen

Question 7

Role of chloride bicarbonate exchanger?

Answer 7

It transports bicarbonate out of the cell and into the blood and chlorine out of the blood and into the cell.

Question 8

Role of chloride potassium symport?

Answer 8

transports potassium and chloride out of the cell into the lumen

Question 9

What is the role of H+/K+ ATPase (proton pump) ?

Answer 9

transports H+ out of the cell and into the lumen and it transports potassium from the lumen into the cell

Question 10

What is the role of carbonic anhydrase?

Answer 10

Its the enzyme that plays a role in the rection of CO2 + H2O= H2CO3-

Question 11

When is histamine released?

Answer 11

enterochromaffin like cells secrete histamine in response to stimulation by acetylcholine

Question 12

What receptors does histamine bind to?

Answer 12

H2 receptors

Question 13

What does the binding of histamine to H2 receptors trigger?

Answer 13

activation of adenylyl cyclase

Question 14

What does activation of adenylyl cyclase trigger?

Answer 14

an increase in cAMP

Question 15

What does an increase in cAMP trigger?

Answer 15

an increase in the number of proton pumps, increasing gastric acid secretion from parietal cells

Question 16

What is ACh released by?

Answer 16

parasympathetic cholinergic neurons

Question 17

What does ACh bind to?

Answer 17

muscarinic (M3) ACh receptors on parietal cells

Question 18

What happens when ACh binds to the M3 ACh receptors on the parietal cells?

Answer 18

Phospholipase C (PLC) is activated

Question 19

What does phospholipase C do?

Answer 19

It increases intracellular Ca2+ levels

Question 20

What does an increase of intracellular Ca2+ lead to?

Answer 20

a number of signalling pathways which leads to an increase in proton pumps and so an increase in the gastric acid secretion (hydrochloric acid) by the parietal cells

Question 21

What does gastrin bind to?

Answer 21

CCK2 receptors on parietal cells

Question 22

What does the binding of gastrin to CCK2 receptor cells trigger?

Answer 22

activation of phospholipase C

Question 23

Where are enterochromaffin, D and G cells located?

Answer 23

the gastric glands

Question 24

What does somatostatin bind to?

Answer 24

SST2R receptors

Question 25

What does binding of somatostatin to SST2R receptors in parietal cells trigger?

Answer 25

inhibition of adenylyl cyclase

Question 26

What does decrease in adenyly cyclase lead to?

Answer 26

decrease in cAMP, decrease in proton pumps and decrease in gastric acid secretion

Question 27

What does binding of somatostatin to SST2R receptors on enterochromaffin cells lead to ?

Answer 27

reduce histamine release

Question 28

what does reduced histamine release cause?

Answer 28

decrease in activated adenylyl cyclase, so decrease cAMP and decrease in number of proton pumps and so causing a decrease in the gastric acid secreted by parietal cells

Question 29

What are examples of antiacids?

Answer 29

Gaviscon and peptac

Question 30

How to antiacids work?

Answer 30

they reduce the symprotms of excessive gastric acid by buffering HCl, this is done by them binding to the excess hydrogen greating H2CO3 which then becomes CO2 and H2O

Question 31

Describe what effect do NSAIDS have on gastric secretion?

Answer 31

NSAIDS inhibit COX-1 decreasing production of prostaglandins, triggering histamine to be produced from the enterochromaffin cells which promotes HCl secretion from the parietal cells

Question 32

What medication can be given to prevent NSAID induced peptic ulcer?

Answer 32

Misoprostol

Question 33

What is misoprostol similar to?

Answer 33

Prostaglandin E1

Question 34

What are the side effects of misoprostol?

Answer 34

abdominal pain, diarrhoea, may induce labour

Question 35

What are examples of proton pump inhibitors?

Answer 35

Lansoprazole, omeprazole, pantoprazole

Question 36

What effect do PPIs have?

Answer 36

irreversibly inhibit H+/K+ ATPase pump, leading to reduction of HCl secretion

Question 37

When are PPIs used?

Answer 37

for benign gastric ulceration, NSAID gastric ulceration, gastro- oesophageal reflux disease and Zollinger-Ellison syndrome

Question 38

What are the side effects of PPIs?

Answer 38

they reduce the pH in stomach, reducing defecne against infection via the GI tract

Question 39

What are examples of histamine antagonists?

Answer 39

ranitidine, cimetidine, famotidine, and nizatidine

Question 40

What do histamine antagonists do?

Answer 40

Block the H2 receptors, eventually leading to decrease in HCl

Question 41

When are histamine antagonsits used?

Answer 41

benign gastric ulceration and NSAID gastric ulceration