Gastric Secretions Flashcards Preview

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Flashcards in Gastric Secretions Deck (25):
1

What are the functions of gastric secretions?

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

2

Role of chief cells

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

3

Role of parietal cells

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

4

Role of ECL cells

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

5

Role of G cells

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

6

Role of D cells

Secretes somatostatin which has a negative feedback role

7

Role of mucin neck cells

Secrete mucus to protect stomach lining

8

Role of stem cells

Differentiate into any of the cells within the gastric pit

9

What areas of the stomach are G cell rich?

Antrum and pylorus

10

What is the alkaline tide?

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

11

What does omeprazole do?

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

12

What does aspirin do to the stomach lining?

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

13

What is intrinsic factor secreted from?

Parietal cells

14

Why is intrinsic factor needed?

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

15

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

- 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

16

What does cimetidine do?

Block histamine receptors

17

When is somatostatin released?

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.

18

Examples of the cephalic reflex regulating acid secretion

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

19

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

Gastric

20

How does the gastric regulation of acid secretion work?

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

21

How does the intestinal regulation of acid secretion work?

Peptide

22

Where is the oxyntic gland area?

Body and fungus

23

Where is gastrin produced?

Antrum in the G cells

24

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

1 billion
150-160mEq/L

25

How much gastric juice does the stomach secrete per day?

1-2L