Lab 1: Presentation 1

Question 1

What does melena mean?

Answer 1

Black stool as a result of an upper GI bleed

Question 2

At what stage of the GI tract if there was a bleed it would be black and why is it black?

Answer 2

A bleed before the jejunum will be black in the stool (melena)

It is black because it has been partially digested

Question 3

What should be done initially when a patient is in heamorrhagic shock?

Answer 3

Give fluids by intervenous injection to increase the blood pressure.

Sample the blood to determine haemoglobin levels (to show if blood needs to be give)

Question 4

What is the normal haemoglobin levels for a female and male?

Answer 4

Female: 110

Male: 130

Question 5

What are the two ways to stop the bleeding for a peptic ulcer?

Answer 5

1. Inject with adrenaline as it is a vasoconstrictor
2. Coagulate the area with a heat probe

Question 6

Answer 6

Question 7

What is the pH of gastric juice?

Answer 7

1.5-3.5

Question 8

What are these?

Answer 8

Gastric pits and Gastric glands

Can be one gastric pit and multiple gastric glands

Question 9

What are the two types of gastric glands that are found in the stomach?

Answer 9

Oxyntic and pyloric glands

Question 10

What region of the stomach are the oxyntic glands found?

Answer 10

The fundus and body of the stomach

Question 11

What region of the stomach are pyloric glands found?

Answer 11

In the pyloric antrum

Question 12

What are the differences between a oxyntic and pyloric gland?

Answer 12

Oxyntic:

Found in the fundus and the body

More parietal cells

High secretion of hydrochloric acid and intrinsic factor

Pyloric:

Found in the pyloric antrum

Less parietal and more G cells

High secretion of gastrin

Question 13

What are the components of gastric juice?

Answer 13

Hydrochloric acid (secreted by parietal cells)

Pepsin (secreted in the form of pepsinogen by chief cells)

Mucin (large glycoprotein, which is a structural component of mucus)

Intrinsic factor (secreted by parietal cells)

Question 14

When the pH begins to fall what gets secreted?

Answer 14

Somatostatin from D cells

Question 15

What cells does the vagus nerve innervate?

Answer 15

ACh (released by the vagus nerve) inhibits D cells, stimulates G cells and parietal cells

Question 16

What receptor does ACh innervate on the parietal cell?

Answer 16

M3 receptor

Question 17

What receptor does the gastrin innervate on the parietal cell?

Answer 17

CCK 2 receptor

Question 18

What cells does the ACh innervate?

Answer 18

Inhibits D cells

Stimualtes parietal cells

Stimulates G cells

Question 19

Name these receptors?

Answer 19

Question 20

Name these cells?

Answer 20

Question 21

What does gastrin do?

Answer 21

Stimulates ECL cells to produce histamine

Stimulates parietal cells to produce acid

Question 22

What does ACh do in the gastric secretion process?

Answer 22

Stimulates G cell to produce gastrin

Stimulates parietal cell to produce acid

Question 23

What does somatostatin do in the gastric secretion process?

Answer 23

Secreted by the D cells

Inhibits parietal cell acid secretion

Inhibits ECL cell histamine secretion

Question 24

What does histamine do in the acid secretion process?

Answer 24

Stimulates parietal cell to produce acid via H2 receptor

Inhibits D cells somatostatin secretion, thus stimulates acid secretion

Question 25

What are the 3 functions of the gastric acid?

Answer 25

Aids digestion- converts pepsinogen to pepsin Absorption of iron, vitamin B12 and calcium Antimicrobial

Question 26

What is the main defence against the gastric acid in the stomach? Why is it such a good defence

Answer 26

The **gastric** **mucus** is the main defence Physical and chemical barrier Chemical: its rich in bicarbonate which neutralises the hydrochloric acid

Question 27

Give examples of too much attack causes that results in peptic ulcer disease?

Answer 27

Zollinger Ellison Syndrome- benign gastric producing tumour *H.pylori* infection

Question 28

Which cyclooxygenase is important in mucus production?

Answer 28

COX-1

Question 29

Why are NSAIDs so dangerous in the stomach?

Answer 29

NSAIDS are non selective inhibitors of COX1 and COX2 COX1 is important for the production of mucus, hence NSAIDs are dangerous and it lowers this protective barrier from the gastric acid

Question 30

Give examples of too little defense causes that results in peptic ulcer disease?

Answer 30

Non steroidal anti-inflammatory drugs aka NSAIDs "*Stress"* ulceration *H.pylori* infection

Question 31

How does the *H.pylori* result in peptic ulcer disease? Is it too much attack or too little defense? Why?

Answer 31

Both attack and defense _Attack_: Blocks D cells, limiting in the inhibition of parietal cells and it secretes ammonia which neutralises the acid. Triggering more acid production _Defense_: causes chronic inflammation of the lining

Question 32

What are *"stress"* ulceration?

Answer 32

It is when an ulceration results in a patient who is under a lot of physiological stress e.g. surgery.

Question 33

What does a peptic ulcer look like in an endoscope?

Answer 33

Looks similar to a mouth ulcer White circular shape on the lining

Question 34

What are some complications of peptic ulcer disease?

Answer 34

Perforation Bleeding Penetration Gastric outlet blockage

Question 35

What is the main cause of peptic ulcer disease?

Answer 35

*H.pylori*

Question 36

Describe the difference in the outcome of *H.pylori* as a result of geographical design?

Answer 36

_Asia_ *H.pylori* predominately results in **pangastritis** Pangastritis: Atrophy of the parietal cells leading to hypochlorhydria (low levels of acid). Increasing the risk of gastric cancer. Effects the entire stomach lining. _West_ *H.pylori* predominately results in **antral** **predominant** **gastritis** Antral predominant gastritis: Excessive acid production but does not cause atrophy. Found in the antrum.

Question 37

What is the main cause of duodenal ulcers?

Answer 37

Usually are a result of acid hypersection from the stomach. The acid moves into the duodenum when chyme travels through.

Question 38

How does *H.pylori* live in the stomach?

Answer 38

It metabolises urea via urease, into ammonia. Ammonia is an alkaline which is secreted around the *H.pylori* creating a buffer zone , as the ammonia neutralises the acid.

Question 39

What are the 5 ways to detect *Helicobacter pylori* ?

Answer 39

Serological (blood) test Stool test Urea breathe test Barium swallow Biopsy urease test

Question 40

What are the pros and cons of the blood test to detect *Helicobacter pylori*?

Answer 40

The test detects IgG antibodies 85% sensitive Can only be used once

Question 41

Describe the urea breathe test for detecting *Helicobacter pylori?*

Answer 41

Patient ingests ¹³C-Urea (isotope 13 for Carbon) If *H. pylori* is present they will convert the ¹³C-urea into ¹³CO₂ and ammonia Test the levels of ¹³CO₂

Question 42

Describe how the barium swallow test can be used to detect *H.pylori?*

Answer 42

Ingests barium If a peptic ulcer is present, it will be filled with barium Can be seen on an X-ray

Question 43

Describe the biopsy urease test (also known as rapid urease test) to detect *Helicobacter* *pylori?*

Answer 43

A biopsy is taken The biopsy is added to a substrate that contains urea and phenol red (hence the red colour) If *H.pylori* is present, it will convert the urea into ammonia, and this will increase the pH. This causes a colour change from red to yellow- positive indication of *H.pylori*

Question 44

What colour is the rapid urease test initially and after a positive result?

Answer 44

Initially it is yellow Positive result, red

Question 45

What are the 4 treatments for peptic ulcer disease?

Answer 45

1. Eradication therapy- antibiotics 2. Medication 3. Lifestyle changes 4. Surgical treatment

Question 46

Describe the medications available to test peptic ulcer disease?

Answer 46

H2 receptor antagonist Proton pump inhibitors

Question 47

Give an example of a H2 receptor antagonist?

Answer 47

Ranitidine

Question 48

Give an example of a proton pump inhibitor?

Answer 48

Omeprazole

Question 49

Describe the way H2 receptor antagonist works in reducing acid secretion?

Answer 49

Competitive and reversibility bind to the H2 receptor on the parietal cells Histamine released by the ECL cell bind to the H2 receptor. Hence the H2 receptor antagonist reduces the histamine effect Reduces acid secretion

Question 50

What are some cons of the H2 receptor antagonist?

Answer 50

Interacts with other drugs "Drug holidays" are required- this is when you have to take breaks when taking a medication because you become tolerant

Question 51

Describe the mechanism of action for proton pump inhibitors?

Answer 51

Taken orally Absorbed in the small intestine It inhibits the potassium/hydrogen ion pump located on the apical membrane of the parietal cell

Question 52

What are some cons of the proton pump inhibitors?

Answer 52

Slight increase in the risk of food poison Rebound acid hypersecretion- when PPI are stopped, there is an increase in acid secretion (higher than it was prior to PPI)