Gastro

Question 1

Where is the vomiting centre located in the brain?

Answer 1

Medulla oblongata

Question 2

Give some examples of trigger points that lead to vomiting:

Answer 2

Labyrinth receptors in ear (eg motion sickness)
Over distension of the gut and stomach
Trigger zone in the CNS (e.g. medications)
Touch receptors in throat i.e. gag point

Question 3

Give an example of a medication that can increase gastric emptying and decreases GI transit time?

Answer 3

Erythromycin

Question 4

List the phases of gastric acid secretion:

Answer 4

1) Cephalic phase
2) Gastric phase
3) Intestinal phase

Question 5

How much of the acid is produced during the cephalic phase?

Answer 5

30%

Question 6

What happens during the cephalic phase?

Answer 6

Smell / taste of food
Vagal cholinergic stimulation leads to secretion of HCL and gastric from G cells

Question 7

What cells are gastrin and HCL released from

Answer 7

G cells

Question 8

What occurs during the gastric phase of of acid secretion?

Answer 8

Stomach distension and low H+ ions
Leads to production of gastrin

Question 9

How much acid is produced during the gastric phase?

Answer 9

60%

Question 10

How much acid is produced during the intestinal phase?

Answer 10

10%

Question 11

Where is the foot in the intestinal phase?

Answer 11

The duodenum

Question 12

What happens to gastric acid secretion during the intestinal phase?

Answer 12

It becomes inhibited by CCK and secretin.

Question 13

List some factors which increase production of gastric acid:

Answer 13

Vagal nerve stimulation
Gastrin release
Histamine release

Question 14

What cells in the stomahc release histamine?

Answer 14

Enterchromaffin like cells

Question 15

List some factors which decrease gastric acid secretion:

Answer 15

Somatostatin
Cholecystokinin
Secretein

Question 16

What cells produce cholecystokinin (CCK) and where are they located

Answer 16

I cells of the upper small intestine

Question 17

List some of the actions of CCK?

Answer 17

• Decreases gastric acid secretion
• Contracts gallbladder
• Relaxes sphincter of Oddi
• Decreases gastric emptying
• Induces satiety

Question 18

Where are G cells located

Answer 18

Antrum of the stomach

Question 19

Gastrin increases gastric motility. True or False

Answer 19

True

Question 20

What cells release secretin?

Answer 20

S cells

Question 21

Where are S cells located?

Answer 21

The upper small intestine

Question 22

List some of the actions of secretin:

Answer 22

• Stimulates secretions by the pancreas and intestines
• Inhibits acid and pepsinogen secretion

Question 23

What cells produce somatostatin?

Answer 23

D cells

Question 24

Where are D cells located?

Answer 24

Pancreas and Stomach

Question 25

List the actions of somatostatin:

Answer 25

- Decrease acid and pepsin secretion - Decrease gastric secretion - Decrease pancreatic enzyme secretion - Decrease insulin and glucagon secretion - Inhibits trophic effects of gastrin - Stimulates gastric mucus production

Question 26

What inhibits gastrin secretion?

Answer 26

Low antral pH Somatostatin

Question 27

List the actions of gastrin:

Answer 27

- Increases HCL - Increases IF secretion - Increase gastric motility - Trophi effect on gastric mucose

Question 28

What cell produces gastric acid?

Answer 28

Parietal cells

Question 29

What is the normal pH of the stomach?

Answer 29

2

Question 30

What is responsible for maintaining the pH / acidity of the stomach?

Answer 30

H+ / K+ ATPase pump

Question 31

Where is bicarbonate secreted during gastric acid secretion?

Answer 31

Into the surrounding vessels via the H+K+ ATPase plant.

Question 32

Where do parietal cells secrete sodium and chloride?

Answer 32

into the canaliculus

Question 33

What maintains the pH of the stomach

Answer 33

The H+/K+ ATPase pump

Question 34

Which of the following would inhibit gastric acid secretion: - Nausea - Vagal / parasympathetic stimulation - Calcium - Histamin

Answer 34

Nausea - works via higher cerebral activity and sympathetic innervation

Question 35

Release of which hormone will be directly impacted by a truncal vagotomy?

Answer 35

Gastrin

Question 36

What part of the GI tract is responsible for the majority of water absorption?

Answer 36

Jejunum

Question 37

Where in the gut is iron absorbed most?

Answer 37

Duodenum

Question 38

What do foveolar cells secrete?

Answer 38

Mucus to protect gastric mucosa