GI pharmacology

Question 1

what do PPIs do

Answer 1

irreversible inhibition by covalent modification of the gastric gland, parietal cell H+/K+ atp ase

Question 2

where is the h+/K+ ATPase present

Answer 2

on the apical canalicular membrane

Question 3

what is the H+/K+ atpase

Answer 3

the final pathway by which gastrin, ach and histamine increase gastric acid production, therefore blocking the h/k ATPase is more effective than h2 antagonists which is a competitive antagonist of H2 receptor and only blocks the action of histamine

Question 4

when are PPIs used

Answer 4

in the treatment of GU, DU and GORD

Question 5

what are some of the side effect to PPIs

Answer 5

are thought to increase the risk of clostridium difficile if used for long term, may disguise gastric cancer, diarrhoea, headache, abdo pain ,nausea and fatigue

Question 6

what does the PPI interact with that can affect the absorption of other drugs

Answer 6

P450

Question 7

what does interaction with P450 do

Answer 7

decrease platelet activity of clopidogrel

increase the effect of phenytoin and warfarin

Question 8

describe the 4 parts to the structure of the internal alimentary canal

Answer 8

most inner layer is the muscosa which is made up of epithelium, lamina propria, a thin layer of looseconnective tissue and the muscularis mucosa-thin layer of smooth muscle
submucosa-loose connective tissue
muscularis externa-circular muscle then longitudinal muscle
serosa or adventitia-outer layer of connective tissue

Question 9

what structures are found in the stomach

Answer 9

gastric pits and at the bottom of the gastric pit are 1-7 gastric glands

Question 10

what is contained within the isthmus of the gastric pit

Answer 10

mostly parietal cells

Question 11

what mutation is present in the HNPCC gene

Answer 11

mutation in DNA mismatch repair gene

Question 12

what cells are present in the neck of the gastric pit

Answer 12

mucous and stem

Question 13

what cells are present in the base of the gastric pit

Answer 13

mostly chief a few parietal and neuroendocrine cells

Question 14

where are parietal cells found

Answer 14

in the isthmus of the gastric pit

Question 15

where are mucous and stem cells found

Answer 15

neck

Question 16

where are chief cells a few parietal and neuroendocrine cells found

Answer 16

base of the gastric pit

Question 17

what layer is increased to form the pyloric sphincter

Answer 17

the inner circular layer is increased to form the pyloric sphincter

Question 18

what does the cardia have

Answer 18

deep gastric pits, that branch into loosely packed tortuous glands

Question 19

what does the body of the stomach have

Answer 19

shallow pits

Question 20

what does the pylorus have

Answer 20

deep gastric pits with branched coiled gastric glands at a higher density than in the cardia

Question 21

what des the small intestine contain

Answer 21

crypts of lieberkuhn

Question 22

what does the duodenum contain and what is so unique about their location

Answer 22

brunners glands in the submucosa, this is unusual as it is the only part of the GI tract with glands in the submucosa

Question 23

where are the plicae circularis located

Answer 23

in the mucosa and submucosa

Question 24

what is located in the mucosa and submucosa of the jejunum

Answer 24

plicae circularis

Question 25

what is contained within the ileum and where

Answer 25

lymphoid follicles called payers patches in the submucosa and often extending into the lamina propria

Question 26

what are enterocytes made of

Answer 26

tall columnar epithelium cells with a brush border

Question 27

what do goblet cells produce and what does this cause

Answer 27

goblet cells produce mucin and this protects the epithelium and lubricates the passagage of material

Question 28

what are the two types of cell in the large intestine

Answer 28

absorptive cells which remove salts and thereby water and goblet cells which serete mucus to lubricate the colon

Question 29

describe some features of the appendix

Answer 29

a blind ending hollow extension of the caecum less crypts than in the colon circular arrangement of lymphoid tissue in submucosa and often lamina propria lymphoid tissue declines with age

Question 30

what is there between the rectum and anal canal

Answer 30

a distinct junction between the mucosa of the rectum and stratified squamous epithelium of anal canal 2-3 cm long canal is then continuous with stratified squamous epithelium of the surrounging skin

Question 31

where is auerbachs myenteric plexus

Answer 31

in between the longitudinal and circular muscle layer

Question 32

where is meissners submucosal plexus

Answer 32

in the submucosa

Question 33

name the 2 parts of the ENS

Answer 33

auerbachs myenteric plexus and meissners submucosal plexus

Question 34

what si the first line investiagation for biliary colic

Answer 34

ultrasound

Question 35

what is the first line investigation for diverticulitis

Answer 35

CT

Question 36

what is the first line investigation for pancreatitis

Answer 36

ultrasouns to exclue gallstones or biliary obstruction and then CT to evaluate complications eg necrosis

Question 37

what is first line investigation for appendicitis

Answer 37

ultrasound

Question 38

what is the first line investigation for a distended abdomen

Answer 38

depends what you think the cause is fluid-ultra sound bowel source-AXR

Question 39

what si the first line investigation for a distended abdomen thought to be caused by bowel

Answer 39

AXR

Question 40

first line investigation for distended abdomen caused by fluid

Answer 40

ultrasound

Question 41

if suspect perforation what investigation do you do

Answer 41

erect CXR

Question 42

what is the first line investigation for jaundice

Answer 42

ultrasound

Question 43

if a post hepatic cause of jaundice was identified on ultrasound what would be the next investigation

Answer 43

ERCP/MRCP

Question 44

if an intrahepatic cause of jaundice was found on ultrasound what investigation would you do next

Answer 44

CT

Question 45

if cirrhosis was seen on ultrasound what investigation would you do next

Answer 45

Biopsy (guided by ultrasound)

Question 46

when are fluoroscopic contrast studies used

Answer 46

if small bowel disease is suspected with strictures wall thickening, fistulation

Question 47

how does plummer vinson present

Answer 47

patient being investigated for anaemia and then complains of dysphagia

Question 48

what can long term oesophageal reflux cause that is benign

Answer 48

a stricture