The Stomach

Question 1

what are the 3 regions of the stomach?

Answer 1

the cardia, fundus and antrum

Question 2

what do parietal cells do

Answer 2

produce HCl

Question 3

what stimulates parietal cells

Answer 3

gastrin, histamine and ACh (from the vagus nerve)

Question 4

what receptors does gastrin act n to activate parietal cells

Answer 4

CCK receptors

Question 5

what receptors does histamine act on to activate parietal cells

Answer 5

H2 receptors

Question 6

what receptors does Ach act on to activate parietal cells

Answer 6

Mcr receptors

Question 7

what is the alkaline tide

Answer 7

during H+ production in the parietal cells, bicarb is also produced, which moves into the blood vessels draining the stomach making the blood here temporarily more alkaline

Question 8

why do parietal cells require lots of mitochondria

Answer 8

they need lots of energy to use the proton pump against a large concentration gradient

Question 9

what do chief cells do

Answer 9

produce pepsinogen

Question 10

what stimulates chief cells

Answer 10

gastrin via the CCK receptor

vagus nerve Ach via the Mcr receptor

Question 11

what do G cells produce

Answer 11

gastrin

Question 12

what stimulates G cells

Answer 12

vagus nerve secreting ACh

amino acids in the stomach

Question 13

what does gastrin do

Answer 13

activate parietal cells

Question 14

what inhibits gastrin production

Answer 14

somatostatin

Question 15

what do enterochromaffin cells do

Answer 15

secrete histamine

Question 16

what stimulates ECL cells

Answer 16

gastrin via the CCK receptor

vagus Ach via the Mcr receptor

Question 17

what role does histamine have in the stomach

Answer 17

activates parietal cells

Question 17

what do D cells do

Answer 17

secrete somatostatin

Question 18

what does somatostatin inhibit in the stomach

Answer 18

G cells and ECL cells

Question 18

what are the roles of stomach acid

Answer 18

• part of the innate immune system
• chemical digestion
• converts pepsinogen into pepsin

Question 19

what types of cells are mostly found in the cardia of the stomach

Answer 19

mucus secreting cells

Question 22

what types of cells are mostly found in the Antrum of the stomach

Answer 22

G cells and D cells

Question 23

what type of cells are mostly found in the fundus/body of the stomach

Answer 23

mucus secreting cells, parietal cells, chief cells

Question 24

what does the stomach do to help protect itself

Answer 24

• bicarbonate rich mucus secretion
• prostaglandins
• high turnover of epithelia

Question 25

what do prostaglandins do in the stomach

Answer 25

increase blood flow to the stomach - this brings more nutrients to the epithelia

Question 26

what inhibits prostaglandin productions

Answer 26

NSAIDs like aspirin

Question 27

how does alcohol affect the stomach

Answer 27

dissolves the mucus layer

Question 28

what are the 3 phases of digestion in the stomach

Answer 28

cephalic gastric intestinal

Question 29

what happens in the cephalic phase of digestion

Answer 29

the smell and chewing of food stimulates parietal and G cells though the vagus nerve

Question 30

what happens in the gastric phase of digestion

Answer 30

stomach distension activates parietal and G cells (through the vagus nerve) amino acids activate G cells enteric NS causes smooth muscle contractions

Question 31

what happens in the intestinal phase of digestion

Answer 31

chyme in the duodenum stimulates gastrin production before the G cells become inhibited

Question 32

what stimulates D cells

Answer 32

when food leaves the stomach, the pH drops as it is no longer being buffered the lower pH activates the D cells

Question 33

what test can be done to diagnose h-pylori

Answer 33

urease breath test

Question 34

what does the urease enzyme do

Answer 34

converts urea into ammonium

Question 35

how can urease damage the stomach

Answer 35

the ammonium produced is directly toxic to cells

Question 36

how does h-pylori cause damage

Answer 36

- through ammonium production which is toxic | - is cytotoxic to the epithelia itself

Question 37

if h-pylori is found in the Antrum what will it cause

Answer 37

duodenal ulceration

Question 38

if h-pylori is found in the body what will it cause

Answer 38

stomach cancer

Question 39

give an example of a proton pump inhibitor

Answer 39

omeprazole

Question 40

give an example of a H2 antagonist

Answer 40

cimetidine

Question 41

what ways are there to treat stomach problems

Answer 41

proton pump inhibitors H2 antagonists stop NSAIDs antibiotics for H-pylori

Question 42

what is GORD

Answer 42

where the stomach contents moves into the oesophagus

Question 43

what causes GORD

Answer 43

lower oesophageal sphincter problems obesity hiatus hernia (upper stomach into the thorax) delayed stomach emptying (increase intra-gastric pressure)

Question 44

what symptoms are seen in GORD

Answer 44

heart burn cough sore throat dysphasia

Question 45

what is Barrett's oesophagus

Answer 45

where reflux causes metaplasia of the stratified squamous epithelia of the oesophagus to convert into simple columnar - increasing the risk of adenocarcinoma

Question 46

how do you treat GORD

Answer 46

antacids H2 antagonists proton pump inhibitors

Question 47

what is gastritis

Answer 47

inflammation of the lining of the stomach

Question 48

what may cause acute gastritis

Answer 48

heavy NSAID use, alcohol, chemotherapy

Question 49

what may cause chronic gastritis

Answer 49

h-pylori, autoimmune disease attacking parietal cells

Question 50

why may an autoimmune disease against parietal cells cause anaemia

Answer 50

as parietal cells produce intrinsic factor which helps in vitamin B12 absorption - without vitamin B12 you will develop anaemia

Question 51

what type of anaemia is developed from a lack of vitamin B12

Answer 51

pernicious anaemia

Question 52

what is peptic ulcer disease

Answer 52

where the mucosa is eroded down through the muscularis mucosa layer

Question 53

what may cause peptic ulcer disease

Answer 53

NSAIDs, h-pylori, stomach acid

Question 54

what are the symptoms of peptic ulcer disease

Answer 54

epigastric pain, weight loss, bleeding (if a vessel is eroded through)

Question 55

why may you get epigastric pain with peptic ulcers

Answer 55

as the stomach is a foregut structure

Question 56

what is Zollinger-Ellison disease

Answer 56

where theres a gastrin secreting tumour - this causes an up regulation of parietal cells causing increased acid production

Question 57

what can happen to the small intestine as a result of Zollinger Ellison

Answer 57

can lead to holes in the small intestine

Question 58

what can cause stress ulcers

Answer 58

burns, sepsis, trauma, multi organ failure

Question 63

when does acid production increase

Answer 63

when amino acids/peptides are detected in the stomach lumen and when the stomach is distended

Question 64

how will H. pylori appear on a gram stain

Answer 64

gram negative helix shaped bacteria

Question 65

how does the mucus layer help protect the stomach

Answer 65

it is strongly alkali so protects it from the acidic conditions

Question 66

where are the cells of the stomach located

Answer 66

within the gastric pits of the stomach

Question 67

why does the pyloric sphincter strongly control what it lets through

Answer 67

in order to ensure it doesn’t overflow the duodenum with liquid chyme as it is still highly acidic

Question 68

how does receptive relaxation prevent reflux

Answer 68

vagally mediated relaxation allows food to enter stomach without raising gastric pressure