Lecture 1

Question 1

What does the cardiac sphincter do?

Answer 1

Controls the movement of fluid

Question 2

What is the pylorus?

Answer 2

A sphincter which is better than the cardiac sphincter and can empty out its material into the duodenum

Question 3

Describe the muscular anatomy of the stomach

Answer 3

Muscle increases from the top to the bottom, there is more muscle in the antrum than in the fundus

Question 4

What is the body of the stomach also called?

Answer 4

The corpus which is Latin for body

Question 5

What are the layers of the stomach wall?

Answer 5

Mucosa, submucosa, muscularis externa and the serosa

Question 6

What produces mucus in the stomach?

Answer 6

Epithelial cells NOT goblet cells

Question 7

When are goblet cells found in the stomach?

Answer 7

The only time goblet cells are found in the stomach is in a pre cancerous stage e.g. gastric metapalasia

Question 8

What is the lamina propria?

Answer 8

A type of connective tissue found under the thin layer of tissues covering a mucous membrane

Question 9

What type of cells are found in the gastric glands?

Answer 9

Mucus secreting neck cells, parietal cells, chief cells and endocrine cells

Question 10

Where do mucus cells migrate to?

Answer 10

They migrate to form the epithelium of the surface of the stomach and they secrete mucus

Question 11

What are gastric pits?

Answer 11

They are indentations in the stomach which are entrances to the tubular shaped gastric glands

Question 12

How often if the epithelium lining of the stomach replaced?

Answer 12

Every 72-96 hours

Question 13

How long is the acid secreting cell life span?

Answer 13

150-200 days

Question 14

What are known to survive longer than epithelial cells?

Answer 14

Glands

Question 15

What do parietal cells secrete?

Answer 15

They secrete an extrinsic factor (VITAMIN B12)

Question 16

What do Enterochromafin secrete?

Answer 16

Serotonin

Question 17

What do Enterochromafin like cell secrete?

Answer 17

Histamine

Question 18

What do D cells secrete?

Answer 18

Somatostatin

Question 19

What do cells in the antrum secrete?

Answer 19

They don’t secrete acid but they do secrete pepsinogen and contain other endocrine cells called G cells which secrete gastrin

Question 20

What is the first line of defence in the stomach?

Answer 20

Mucus is the first line of defence against gastric juice - which is secreted by epithelial cells

Question 21

What cells line the oesophagus?

Answer 21

Stratified squamous cells

Question 22

Describe the gastric mucus layer

Answer 22

It is a bilateral which protects the stomach from gastric juices, consisting of 2 layers of

Question 23

What are the two layers in the gastric mucus bilayer?

Answer 23

A shear compliment layer and a shear resistance layer

Question 24

What happens to the shear compliant layer when force is applied?

Answer 24

It becomes a viscous liquid - lubricant

Question 25

What happens to the shear resistance layer when force is applied?

Answer 25

It remains intact

Question 26

How many microns thick is the resistant layer?

Answer 26

150 microns

Question 27

How thick is the compliant layer?

Answer 27

It has a variable thickness

Question 28

What maintains the mucus layer?

Answer 28

Secretion and degradation are important in maintaining the balance - a dynamic balance is important in maintaining the thickness of the mucus layer

Question 29

What is the composition of gastric juice?

Answer 29

Mucus, lipases, pepsins, intrinsic factor, water, ions and salivary amylase

Question 30

Where is acid produced in the stomach?

Answer 30

It is only produced in the fundus and corpus of the stomach so lipase is only activated here

Question 31

What is the optimal pH for lipase?

Answer 31

pH7

Question 32

What can be used to stimulate acid secretion?

Answer 32

Histamine and gastrin

Question 33

What pumps are used for acid secretion?

Answer 33

H+/K+, they are trafficked into the membrane during acid secretion and require ATP

Question 34

What is tubulocisternae?

Answer 34

When there is a stimulus for acid secretion, they move along to the membrane and secrete acid

Question 35

What are tubulocisternae supposed by?

Answer 35

An actin scaffold

Question 36

What happens to the actin scaffold when there is a stimulus to stop acid secretion?

Answer 36

The actin scaffold is dissolved

Question 37

What is a treatment for a gastric ulcer?

Answer 37

H2 antagonist - which are the receptors that have been stimulated to secrete acid

Question 38

What is another treatment for gastric ulcers?

Answer 38

Proton pump inhibitors e.g. omeprazole which inhibit the function of the proton pumps

Question 39

What happens in acid secretion?

Answer 39

Carbonic anhydride dissociates into H+ and bicarbonate. Bicarbonate is transferred out cross the basolateral enxyme.

Question 40

What is the proton pump used for in acid secretion?

Answer 40

Transferring K+ coming in and H+ coming out

Question 41

What is an active ingredient?

Answer 41

Sulfenimide - it has a spare SH group so it can form disuphide bridges with cystine

Question 42

What is bad about people who are taking proton pump inhibitors?

Answer 42

If you are told to stop taking them usu will have a huge acid secretion and that can cause damage so you have to keep taking the tablets