Gastro

Question 1

What cells secrete gastrin?

Answer 1

G cells in antrum of stomach

Question 2

What stimulates gastrin secretion from G cells in antrum?

Answer 2

Gastric distension.
Amino acids in the antrum.

Question 3

What does gastrin do?

Answer 3

Acid secretion
Secretion of peptin, gastric acid and intrinsic factor.

Question 4

What cells secrete secretin?

Answer 4

S cells in duodenum/ jejunum/ SI

Question 5

What activates secretin?
What are its actions

Answer 5

Acid in small bowel.

Delays gastric emptying.
Pancreatic bicarbonate secretion.

Question 6

What stimulates secretion of CCK-PZ?

Answer 6

Fat, amino acids and peptides in the small bowel

Question 7

What are the actions of CCK-PZ?

Answer 7

Pancreatic enzyme secretion.
Gallbladder contraction.
Delays gastric emptying

Question 8

What are the actions of gastric inhibitory peptide?

Answer 8

Inhibits gastric acid secretion.
Stimulates insulin secretion.
Reduces mobility

Question 9

Name three gastric hormones that reduce acidity
Where in body are they secreted from

Answer 9

CCK
Secretin
GIP

Duodenum, jejunum, SI

Question 10

What cells secrete somatostatin

Answer 10

D cells in pancreasW

Question 11

What activates somantostatin release

Answer 11

Vagal and adrenergic stimulation

Question 12

What is role of somatostatin

Answer 12

Inhibits gastrin and pancreatic secretion

Question 13

What hormones stimulates release of bile from gallbladder?

Answer 13

CCK

Question 14

4 factors that increase iron absorption?

Answer 14

Increased erythropoesis eg pregnancy
Decreased body iron
Vitamin C
Gastric acid (latter two by converting Fe3+–>Fe2+)

Question 15

4 factors that decrease iron absorption

Answer 15

Gastrectomy
Small bowel disease
Some medications
Low levels of HCl

Question 16

Describe B12 absorption

Answer 16

B12 is ingested, binds to instrinsic factor in the stomach and is absorbed in the terminal ileum

Question 17

Briefly describe the pathophysiology of pernicious anaemia

Answer 17

Autoantibodies against intrinsic factor and gastric parietal cells.
ABs against instrinsic factor block B12 receptors.
ABs against parietal cells reduce acid production, leading to atrophic gastritis and reduced IF production.

Question 18

Only way to test for H. Pylori eradication?

Answer 18

Urea breath test

Question 19

Eradication for H. Pylori? How long for?

Answer 19

PPI
Amoxicillin
Clari/ metro.
If pen allergic, no amox, both clari and metro

1 week

Question 20

In H.Pylori -ve dyspepsia, how long should you prescribe PPI for?

Answer 20

4 weeks

Question 21

Name 4 conditions associated with H. Pylori. Which has strongest association

Answer 21

Peptic ulcers
B cell lymphoma MALT tissue
Atrophic gastritis
Gastric cancer

Question 22

How long need to be off abx and PPI before checking for H. Pylori

Answer 22

4 weeks off abx
2 weeks off PPI

Question 23

Brief pathophysiology of zollinger-ellison syndrome?

Answer 23

Gastrin secreting adenocarcinoma (usually in pancreas or small intestine) leads to multiple GI ulcers.

Question 24

How is zollinger-ellison initially diagnosed

Answer 24

High fasting serum gastrin levels over 3 different days.
Increased secretin can also be useful

Question 25

Management of zollinger-ellison

Answer 25

High dose PPI
Resection if possible
Somatostatin analogue to reduced gastric secretion

Question 26

MOA octerotide. When may it be used?

Answer 26

Somatostatin analogue
Zollinger-ellison, anecdotal evidence for dumping syndrome

Question 27

Pathophysiology of early onset dumping syndrome

Answer 27

Within 1/2 hour of eating
Vagally mediated response to gastric emptying

Question 28

Pathophysiology late onset dumping syndrome

Answer 28

1-3 hours.
Rebound hypoglycaemia following hyperglycaemia caused by carbs in small intenstine

Question 29

What may be found on biopsy of gastric carcinoma

Answer 29

Signet cells

Question 30

True or false- more signet cells= worse prognosis of gastric cancer

Answer 30

True.