Gastric secretion

Question 1

What is secreted in the body of the stomach

Answer 1

Mucous
HCL
Pepsinogen
Intrinsic factor

Question 2

What secretes Mucous in the stomach

Answer 2

Foveolar cells, found in the necks of the gastric pits (Mucous neck cells)

Mucus-secreting cells are the most abundant cell type in the stomach, giving indications of how important mucus is to the functioning stomach.

Question 3

What cell secretes HCL

Answer 3

Parietal cells

Question 4

What cell secretes pepsinogen

Answer 4

Chief cells

Question 5

What cell secretes intrinsic factor

Answer 5

Parietal cells

Question 6

What cell secretes Gastrin

Answer 6

G cells

Question 7

What cells lie in the gastric pit

Answer 7

Surface mucous cells

Question 8

What cells lie in the Gastric gland

Answer 8

Mucous necks cells
Parietal cells
Chief cells

Question 9

What is the pH of the stomach

Answer 9

2

Question 10

What is the pH of blood

Answer 10

7.4

Question 11

How is HCL made in the stomach

Answer 11

Process involving carbonic anhydrase and carbonic acid

Question 12

What pumps H ions out of the apical membrane of the gut cells

Answer 12

A hydrogen/potassium pump (uses lots of ATP)

Question 13

How does bicarbonate exit the enterocyte

Answer 13

Through the baso-lateral membrane via a HCo3 / Chlorine pump.

Question 14

What happens when Hco3 is dumped in blood after meal

Answer 14

Post prandial alkalosis

Question 15

What controls the amount of HCL created by parietal cells (x4)

Answer 15

Gastrin
Histamine
Acetylcholine
Prostaglandins

Question 16

What organs secrete gastrin

Answer 16

Stomach (antrum)
Pancreas
Duodenum

Question 17

What increases the amount of gastrin secretion

Answer 17

peptides, amino acids and gastric distension
vagal stimulation by gastrin releasing peptide
epinephrine and calcium

Question 18

What does gastrin act on?

Answer 18

CCKB gastrin receptors on the basolateral membrane of parietal cells

Question 19

What happens when CCKB gastrin receptors on the basolateral membrane of parietal cells bind gastrin

Answer 19

Calcium is released into the cell which activates protein kinase C and increases activity of the Hydrogen/potassium pump.

Question 20

What causes the release of histamine in the stomach

Answer 20

Gastrin and acetylcholine

Question 21

What releases histamine

Answer 21

Enterochromaffin-likecells

Question 22

What are Enterochromaffin-likecells

Answer 22

A type of neuroendocrinecellfound in thegastricglands of thegastricmucosa beneath the epithelium, in particular in the vicinity of parietalcells, that aid in the production ofgastricacid via the release of histamine.

Question 23

What does histamine act on

Answer 23

The H2 receptors in the stomach

Question 24

What happens when histamine binds to the H2 receptors in the stomach

Answer 24

It activates g protein adenylate cyclase which acts on protein kinase C. This increases action of the H/Cl pump - increases Hydrogen

Question 25

What causes the release of acetylcholine involved in HCL secretion during the cephalic phase

Answer 25

Thinking, seeing, smelling, tasting FOOD

Question 26

What receptor does acetylcholine act on in the stomach to increase acid production?

Answer 26

The M3 receptor on the stomach (via long and short reflexes)

Question 27

What happens when acetylcholine acts on the M3 receptors of the stomach

Answer 27

Increases intracellular calcium which activates protein kinase C - this increases H/CL pump

Question 28

What effect do prostaglandins have on Hydrogen secretion

Answer 28

they inhibit it

Question 29

What receptor does prostaglandins act on

Answer 29

E3 receptors

Question 30

What happens when prostaglandins act on E3 receptors

Answer 30

It activates G inhibitory protein which turns off adenyl cyclase and reduces activity of the h/cl pump

Question 31

Where are prostaglandins found in the stomach

Answer 31

Prostaglandins are found in high concentration in the gastric mucosa and gastric juice.

Question 32

What 3 stimuli cause increased Hydrogen increase during the gastric phase

Answer 32

Distension of Stomach peptides in the lumen Gastrin + Acetylcholine

Question 33

How does distension of stomach increase acid production

Answer 33

It initiates a vagal/enteric reflex, releasing acetyl choline. This causes the parietal cells to release H ions

Question 34

How do peptides in the lumen increase acid production

Answer 34

They activate G cells which releases Gastrin which act on parietal cells

Question 35

How does gastrin and acetyl choline increase acid production together?

Answer 35

They both act on enterochromaffin cells causing them to release histamine which acts on parietal cells

Question 36

What Inhibits gastric acid secretion in the cephalic phase

Answer 36

When you stop eating it decreases vagal activity so Ach and H+ stops getting produced

Question 37

What Inhibits gastric acid secretion in the gastric phase

Answer 37

When the Ph gets reduced to a certain level due to an abundance of stomach acid, gastrin secretion gets reduced from G cells

Question 38

What stimulus reduces gastric acid secretion in the intestinal phase (x2)

Answer 38

Acid in duodenum | Fat/CHO in duodenum

Question 39

How does acid in duodenum inhibit gastric secretion

Answer 39

It triggers the enterogastric reflex and the release of secretin from S cells. The secretin produces bicarbonate, decreases gastrin secretion and stimulation of parietal cells.

Question 40

How does fat/CHO in the duodenum inhibit gastric secretion

Answer 40

It triggers the releases of Gastroinhibitory peptide (GIP) | This decreases gastrin secretion and hence decreases gastrin stimulation of parietal cells

Question 41

What is the collective term for an inactive precursor enzyme

Answer 41

Zymogen

Question 42

What activates pepsinogen

Answer 42

Low pH (<3)

Question 43

What lines the stomach surface

Answer 43

Gastric Mucous

Question 44

What produces gastric mucous in the stomach (x2)

Answer 44

Surface cells | Mucous neck cells

Question 45

What are 2 functions of gastric mucous

Answer 45

Protects against gastric acid corrosion | Protects from mechanical injury