Lecture 3

Question 1

What is pepsin?

Answer 1

It is an acidic protein in gastric juice

Question 2

What happens to pepsin when the stomach empties?

Answer 2

It empties through the pylorus and squirts onto the duodenum which is where stomach ulcers are found

Question 3

How can you stimulate acid in the stomach?

Answer 3

By gastrin

Question 4

How many different amino acids of gastrin are there that can stimulate acid secretion?

Answer 4

5 amino acids

Question 5

What can stimulate pepsin secretion?

Answer 5

Insulin

Question 6

What is the major pepsin in man?

Answer 6

Pepsin 3

Question 7

What Pepsin is more likely to degrade mucus?

Answer 7

Pepsin 1 - there is a 2 fold increase in pepsin 1 than pepsin 2 at pH2

Question 8

What happens if the pH is 4 with pepsin?

Answer 8

Pepsin will have a 6-fold inference which is damaging to the mucosa

Question 9

What is the gastric juice in gastric ulcers likely to do?

Answer 9

It can degrade the mucosal barrier

Question 10

What is pepsinogen stable up to?

Answer 10

PH10 and 11

Question 11

When does pepsin start to denature?

Answer 11

PH7 - it is effectively denatured (where it becomes inactive), above pH8 pepsin can’t be recovered it is irreversibly denatured

Question 12

At what pH does a lot of digestion take place in gastric juice?

Answer 12

pH 2

Question 13

What are 5 diseases associated with reflux?

Answer 13

GORD, OME (glue ear), LPR, rhinitis and sinusitis and vocal folds epithelial cell hyperplasia

Question 14

What is a treatment for glue ear?

Answer 14

Put a hole in the ear drum and fit a grommet to suck out the liquid in the ear - contains a lot of mucus

Question 15

What is larangomalacia?

Answer 15

Incomplete development of the larynx in children, collapses and it gets hard to breathe

Question 16

What are the two sphincters for probe monitoring - measuring pH?

Answer 16

Upper Oesophageal sphincter - one probe sits outside, and an oesophageal probe which sites 5 centimetres above the lower oesophageal sphincter

Question 17

What is the oesophageal sphincter also known as?

Answer 17

The cardiac sphincter

Question 18

What is positive pharyngeal reflux event?

Answer 18

A drop below pH 4 at the top of the oesophagus preceded by a precipitous drop at the distal probe

Question 19

Is pH4 damaging?

Answer 19

Yes - even if you were to put a pH of 3.5 on a living tissue it would cause cell death

Question 20

Why would you look at sputum if a patient had reflux?

Answer 20

Because the sputum of the patient should have pepsin present

Question 21

What is measured to measure the sputum sample?

Answer 21

A SLOT BLOT - with a nitrocellulose membrane and a vacuum system

Question 22

Does pepsin increase reflux in a higher pH?

Answer 22

Yes from pH2 to Ph5 there are more reflux events as pH is increased.

Question 23

What is the highest pH that pepsin can work at?

Answer 23

PH6.5 , 50% of activity is at pH 3.5

Question 24

what are two techniques that can be used to measure functional pepsin?

Answer 24

ELISA technique and an activity assay

Question 25

what is the standard diagnosis of reflux?

Answer 25

24 hour double-probe pH monitoring