Gastric Secretions

Question 1

What are the functions of gastric secretions?

Answer 1

• Digestion of proteins
• Protection of the stomach lining
• Absorption of VB12
• Protection again food-borne infections
• Helps convert enzymes to active form

Question 2

Role of chief cells

Answer 2

Secrete pepsinogen, precursor of the active pepsin which breaks down proteins

Question 3

Role of parietal cells

Answer 3

Secrete HCl (gastrin acid), decreasing stomach pH and is where intrinsic factor is released

Question 4

Role of ECL cells

Answer 4

Entero-chromaffin like cells which are always close to parietal cells. Secrete histamine which is a trigger for gastric acid release

Question 5

Role of G cells

Answer 5

Release gastrin hormone, which then stimulates the ECL cells and cause acid secretion, cascade effect

Question 6

Role of D cells

Answer 6

Secretes somatostatin which has a negative feedback role

Question 7

Role of mucin neck cells

Answer 7

Secrete mucus to protect stomach lining

Question 8

Role of stem cells

Answer 8

Differentiate into any of the cells within the gastric pit

Question 9

What areas of the stomach are G cell rich?

Answer 9

Antrum and pylorus

Question 10

What is the alkaline tide?

Answer 10

More acid is secreted after eating so more OH- ions are removed into the blood as HCO3- . Acid one way, base the other.

Question 11

What does omeprazole do?

Answer 11

Antacid, blocks the H+/K+ transporter, preventing acid secretion. Sits in the stomach lumen and is activated by a low pH.

Question 12

What does aspirin do to the stomach lining?

Answer 12

PG inhibitor so disrupts the mucus and bicarbonate layer protecting the stomach.

Question 13

What is intrinsic factor secreted from?

Answer 13

Parietal cells

Question 14

Why is intrinsic factor needed?

Answer 14

VB12 absorption, a lack causes pernicious anaemia, which is treated with a cyanocolbalmin injection

Question 15

What are the 3 ways that causes acid to be secreted into the stomach?

Answer 15

• Ach acting directly on the parietal cells causing H+ secretion.
• ACh acting on the G cells that produce gastrin, which acts directly on the cell causing H+ secretion.
• Gastrin production acting on the ECL cells, increasing histamine and acid secretion

Question 16

What does cimetidine do?

Answer 16

Block histamine receptors

Question 17

When is somatostatin released?

Answer 17

After the ingestion of food when stomach pH is low , D cells secrete somatostatin, which is a peptide hormone and has a negative feedback effect on gastrin.

Question 18

Examples of the cephalic reflex regulating acid secretion

Answer 18

• Food in mouth leads to the secretion of HCL
• Anger and tension increases acid secretion
• Fear and depression decreases acid secretion

Question 19

Which is the most dominant regulator of acid secretion in the stomach?

Answer 19

Gastric

Question 20

How does the gastric regulation of acid secretion work?

Answer 20

Stimulated by distension of the stomach (vast-vagal), hyperoncity, alcohol and AAs.
Inhibited by H+

Question 21

How does the intestinal regulation of acid secretion work?

Answer 21

Peptide

Question 22

Where is the oxyntic gland area?

Answer 22

Body and fungus

Question 23

Where is gastrin produced?

Answer 23

Antrum in the G cells

Question 24

How many parietal cells are in the human stomach and what is the concentration of the acid they produce?

Answer 24

1 billion

150-160mEq/L

Question 25

How much gastric juice does the stomach secrete per day?

Answer 25

1-2L