Basic Gastric Physiology

Question 1

What are the two regions of the stomach?

Answer 1

Oxyntic Mucosa

Antral Region

Question 2

What cells are contained in the OM?

Answer 2

Parietal Cells
Chief Cells
ECL Cells

Question 3

What do Parietal Cells secrete?

Answer 3

Gastric Juice (HCL) and Intrinsic Factor

Question 4

What does Chief cells secrete?

Answer 4

Pepsinogen

Question 5

What do Enterochromaffin Like Cells secrete? (ECL cells)

Answer 5

Histamine

Question 6

What cells are contained in the Antrum?

Answer 6

G Cells

D Cells

Question 7

What do G cells secrete?

Answer 7

Gastrin

Question 8

What do D cells secrete?

Answer 8

Somatostatin

Question 9

Where are most functional cells found?

Answer 9

Gastric Pits

Question 10

Where are the endocrine cells found?

Answer 10

Bottom of the gastric pits

Question 11

Where are the mucous cells found?

Answer 11

Top of the gastric pits

Question 12

Explain the location of cells in gastric pits?

Answer 12

Endocrine cells are at the bottom and mucous cells are at the top to produce an alkaline layer of mucous to protect the cells from the acidic secretion of the OM

Question 13

The higher the rate of secretion of gastric juices by parietal cells, the more/less acidic it is?

Answer 13

More acidic

Question 14

Describe pernicious anaemia?

Answer 14

This is caused by B12 deficiency. It can be caused by destruction of the OM as this is where the parietal cells that secrete intrinsic factor are located. intrinisc factor binds to B12 and allows it to be absorbed in the distal ileum.

Question 15

What does Gastrin do?

Answer 15

Increases gastric acid secretion and prepares the rest of the stomach for digestion

Question 16

Where is Gastrin secreted from?

Answer 16

G cells of the Antrum

Question 17

What stimulates Gastrin secretion?

Answer 17

ACh released from vagus nerve in response to a food bolus in the stomach
Amino acids and peptides in the stomach

Question 18

What does Histamine do?

Answer 18

Increases acid secretion

Question 19

What receptors does Histamine act on?

Answer 19

H2 receptors of parietal cells

Question 20

What stimulates Histamine secretion?

Answer 20

ACh and Gastrin

Question 21

Where is Histamine secreted from?

Answer 21

Enterochromaffin Like Cells (ELC) in the OM

Question 22

What does Somatostatin do?

Answer 22

Inhibits gastric acid secretion

Question 23

Where is Somatostatin released from?

Answer 23

D cells of the Antrum

Question 24

What is CCK?

Answer 24

Is it a digestive hormone

Question 25

What stimulates CCK?

Answer 25

Stimulated by the presence of food in the stomach or small intestine

Question 26

What does CCK do?

Answer 26

Acts on the gallbladder causing it to secrete bile into the small intestine

Question 27

Describe the role of Secretin and VIP

Answer 27

These are released by the duodenum | They inhibit gastric acid secretion

Question 28

Describe the affect of parasympathetic stimulation on gastric digestion?

Answer 28

Increased motility | Increased secretion

Question 29

Describe the affect of sympathetic stimulation on gastric secretion?

Answer 29

Decreased Motility | Decreased Secretion

Question 30

Gastrin: Produced where? Acts on what? Causes what? Stimulated y what?

Answer 30

``` G Cells Stomach Releases HCl and Pepsin Contracts pyloric region Increased motility - Food Bolus (Vagus nerve) And amino acid/peptide presence in stomach ```

Question 31

CCK: Produced where? Acts on what? Causes what? Stimulated by what?

Answer 31

Small Intestine Gall Bladder Releases Bile - Food bolus in stomach

Question 32

Secretin: Produced where? Acts on what? Causes what? Stimulated by what?

Answer 32

``` Duodenum Acts on pancreas Causes water and bicardbonate secretion (Dilutes HCl) Inhibits gastrin secretion - Low pH ```