Physiology and Pharmacology - Gastric Gland Secretions Flashcards Preview

1st Year - Gastroenterology > Physiology and Pharmacology - Gastric Gland Secretions > Flashcards

Flashcards in Physiology and Pharmacology - Gastric Gland Secretions Deck (28)
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1
Q

What type of cells are present in the pyloric gland area (antrum)? (2)

A

D cellsG cells

2
Q

What type of cells are present in the oxyntic mucosa in fundus and body of the stomach? (3)

A

Chief cellEnterochromaffin-like cellParietal cells

3
Q

What do D cells secrete?

A

Somatostatin

4
Q

What do G cells secrete?

A

Gastrin

5
Q

What do chief cells secrete?

A

Pepsinogen

6
Q

What do enterochromaffin-like cells secrete?

A

Histamine

7
Q

What do parietal cells secrete?

A

Hydrocholric acidIntrinsic factor

8
Q

What does pepsinogen released from chief cells do?

A

Precursor of pepsin which when activated by HCl becomes pepsin

9
Q

What does histamine released from enterochromaffin-like cells do?

A

Stimulates HCl secretion

10
Q

What does hydrochloric acid secreted from parietal cells do?

A

Activates pepsinogen to pepsinDenatures proteinKills most micro-organisms ingested

11
Q

What does intrinsic factor released from parietal cells do?

A

Binds vitamin B12 allowing adsorption in the terminal ileum

12
Q

What does somatostatin released from D cells do?

A

Inhibits HCl secretion

13
Q

What does gastrin released from G cells do?

A

Stimulates secretion of HCl acid

14
Q

What is the full name of the proton pump?

A

H+/K+ATPase (pumps H+ out and K+ in)

15
Q

Where does the Cl- come from that makes HCl?

A

It is pumped into the cell via the Cl-/HCO3- antiporter and is then pumped into the caniliculis via a Cl- channel

16
Q

What 3 regulatory molecules stimulate HCl secretion?

A

AChHistamine Gastrin

17
Q

What receptor does ACh stimulate acid secretion via?

A

M3

18
Q

How does ACh stimulate secretion of HCl?

A

When M3 is activated, it stimulates the proton pump and hence secretion of H+It also acts on M1 receptors on Enterochromafin like cells causing the release of histamine

19
Q

How does histamine stimulate secretion of HCl?

A

It acts on an H2 receptor on the membrane of parietal cells increasing the activation of the proton pump

20
Q

How does gastrin increase secretion of HCl?

A

It stimulates gastrin receptors which increase activation of the proton pumpGastrin also stimulates ECL cells increasing histamine release

21
Q

What inhibits HCl release? How?

A

Somatostain inhibits the release of gastrin and histamineProstoglandin E2 stimulates prostoglandin receptors on parietal cells inhibiting the action of ACh, gastrin and histamine

22
Q

What is a secretagogue?

A

A substance that causes another substance to be secreted

23
Q

How are proton pumps activated? e.g. by histamine, ACh and gastrin

A

Causes the insertion of the proton pump into the apical membrane - through protein kinases

24
Q

What are the 3 phases of gastric secretion?

A

Cephalic (before food reaches the stomach)Gastric (when food is in the stomach)Intestinal (after food has left the stomach)

25
Q

What happens during the intestinal stage of gastric secretion?

A

Factors originating from the small intestine switch off acid secretion

26
Q

What effects do prostaglandins have locally in the stomach?

A

Reduce acid secretionIncrease mucus and bicarbonate secretionIncrease mucosal blood flow

27
Q

What is a peptic ulcer?

A

An area where the mucosa is exposed to HCl and pepsin

28
Q

What is Zollinger-Ellison syndrome?

A

Rare, gastrin producing tumour

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