Physiology and pharmacology of the stomach

Question 1

What are the 2 regions of the stomach?

Answer 1

• orad stomach (proximal)
• caudad stomach (distal)

Question 2

What contractions occur in the orad caudad stomach?

Answer 2

orad stomach

•tonic contractions, when they occur, are weak due to relatively thin musculature

caudad stomach

•phasic peristaltic contractions progress from midstomach to gastroduodenal junction, propelling contents towards pylorus through which a very small volume of chyme flows into the duodenum

Question 3

What determines escape of chyme through pyloric sphincter?

Answer 3

Strength of antral wave determines escape of chyme through pyloric sphincter

Question 4

For considerations of secretion the mucosa of the stomach is classed as what?

Answer 4

•the oxyntic gland area (proximal)

• the pylorlic gland area (distal)

Question 5

What Secretes HCl (hydrochloric acid) and where is it present?

What are the three important secretagogues that induce acid secretion from the parietal cell?

Answer 5

Secretion of HCl by the Gastric Parietal Cell, Present in gastric glands of the oxyntic mucosa.

The three important secretagogues that induce acid secretion from the parietal cell are ACh, gastrin and histamine

Question 6

What 3 phases control the rate of gastric sectretion?

Answer 6

Cephalic phase

Gastric phase

Intestinal phase

Question 7

What are 2 mucosal strengtheners?

Answer 7

ØBismuth chealate

Sucralfate

Question 8

What is a peptic ulcer?

What can Non-steroidal anti-inflammatory drugs cause and how can it be prevented?

Answer 8

• Peptic ulcer refers to any ulcer in an area where the mucosa is exposed to HCl and pepsin (stomach, duodenum)
• Non-steroidal anti-inflammatory drugs (NSAIDs; e.g. aspirin) reduce prostaglandin formation and may:

1. trigger gastric ulceration
2. cause bleeding

Prevented by a stable PGE1 analogue (i.e. misoprostol, but has adverse effects