Which cells of the GIT release secretin?
What is a normal ratio of villus height to crypt depth?
What degree of amplification is achieved in the small intestine by the microvilli?
What effect does caesarian section have on microbiota?
Restricts microbiota diversity
What caues pancreatic release of alpha amylase?
Where is the final stage of peptide digestion?
At the brush border and in the enterocyte
Which germ layer does the wall of the gut come from?
What do the names of proton pump imhibitors end with?
Which drugs were used to treat peptic ulcers before PPIs were invented?
What is magnesium hydroxide used to treat?
Where is the vomit centre?
dorsolateral reticular formation in floor of 4th ventricle in medulla oblongata
Which receptors should be targetted for treatment of nausea associated with motion sickness?
Muscarinic and H1
What do we call the macrophages on the inner walls of hepatic sinusoids?
Some people who are overfed will not put on weight...why not?
They increase NEAT non-exercise activity thermogenesis eg fidgeting
How is acute viral hepatitis differentiated from chronic hepatitis?
Acute infection shows elevated IgM
Chronic infection shows to IgG
What percentage of regular IVDUs are HCV positive?
What are the most common viral causes of chronic hepatitis?
HBV and HBC
How is chronic hepaptitis staged?
Degree of fibrosis
What is the most common type of steatosis?
How does the vagus nerve directly stimulate acid release in the stomach?
Vagal preganglionic cell ACh --> AChNR on post ganglionic --> releases ACh --> AChMR on Parietal cells --> HCl
What percentage of diarrhoea is due to bacteria in developed countries?
Where does human papiloma virus like to infect?
Basal keratinocytes of transformational zone of cervix
What is the hallmark pathological feature of acute and chronic viral hepatitis?
What must be produced to cause haemolytic-uremic syndrome?
Shiga toxin aka verotoxin
Which intestinal lumenal transporter is inactivated during diarrhoea?
What type of muscle is in the esophageal wall?
Skeletal muscle proximally and smooth muscle distally
In which parts of the GIT are stem cells present?
What do Brunner's glands in the GIT do?
Secrete an alkaline mucous (mucous and bicarbonate) to neutralise acid from stomach
What do G cells of the GIT release?
What do we call delayed gastric emptying?
What is the definition of chronic gastritis?
Stomach inflammation sustained for > 3 months
What is the role of M cells in the GIT?
Located over lymphoid aggregates and let antigens and microbes into gut for access to adaptive immune system
What happens to dietary fibre?
Metabolised by bacteria in proximal colon to produce short chain fatty acids, which are then absorbed in distal small bowel and proximal colon
What percentage of live births have a birth defect?
In the portal lobule model of the liver, what is at the centre?
Which hepatitis viruses have a vaccine?
A, B and D
How is HAV excreted?
What colour is bilirubin?
How is bilirubin trasnported in the blood?
Bound to albumin
Which bacteria uses Tir to gain entry to the host cell?
Enteropathogenic E. coli
What is the leading cause of liver transplant?
Infrequent or normal frequency, but much more watery with larger volumes would suggest what type of diarrhoea?
Diarrhoea of small intestine
Which state of Australia has the highest rates of hepatitis A?
What is choledocholithiasis?
blockage of the bile duct
Where do hepatic sinusoids drain?
What do parietal cells of the stomach produce?
HCl and intrinsic factor
What % of people with long-standing GORD develop Barrett's oesophagus?
How is hepatitis E virus transmitted?
How can antibiotics cause diarrhoea?
Broad spectrum antibiotics can alter gut microbiota and cause overgrowth of Clostridium difficile
Which cells secrete HCl in the stomach?
A new drug is on the market, it is called braprazole. What type of drug is it likely to be?
Proton pump inhibitor
What is an omphalocele?
Failure of hernaited gut to retract into coelom before it closes over
Name two D2 antagonists used to treat nausea
What is kernicterus?
Bilirubin-induced brain dysfunction
What is a councilman body?
How is acute hepatitis defined in terms of blood tests?
Raised ALT < 6 months
What gives urine its yellow colour?
Which two toxins does enterotoxic E. coli use?
Heat labile toxin (LT) and head sensitive toxin (ST)
What will the sight, smell and taste of food trigger?
Salivation, gastric acid secretion, pepsin secretion and relaxation of gastric corpus and fundus
What do we call a finger-like extension of the mucosa of the GIT?
What defines Marsh type 2 coeliac disease?
What drug is a systemic antacid?
What does the submucosa contain?
Dense, irregular connective tissue with nerves, small ganglia and blood vessels
How much can the stomach increase in size when full of food?
What catalyses biliverdin --> bilirubin?
Which genes are implicated in coeliac disease?
HLA-DQ2 and HLA-DQ8
What is the degree of leptin synthesis proportional to?
Size of fat storage
Which zone of the acinar model is most vulnerbale to paracetemol toxicity?
What is the main form of cell death in chronic hepatitis?
In regulation of eating, the arcuate nucleus of the hypothalamus projects to which other hypothalamic areas?
What is the main immediate treatment goal in diarrhoea and how is this achieved?
Replace fluids and electrolytes with oral rehydration
What type of epithelium is in the esophagus?
Stratified squamous, non-keratinizing
How does alpha amylase work?
Breaks alpha 1,4 linkages between glucose molecules
What happens to fatty acids and monoglycerides inside enterocytes?
They are formed into triglycerides in the smooth endoplasmic reticulum, then packaged into chylomicrons and secreted into lymphatics
What liver pathology is seen in alcoholic hepatitis?
Mallory bodies and hepatocyte swelling
How much does 1 standard rink raise BAC by?
How is glucose absorbed by enterocytes?
SGLT1 Sodium-dependent glucose trasnporter 1
What is the lifespan of a hepatocyte?
What defines Marsh type 1 coeliac disease?
Increased lymphocyte:enterocyte ratio (>30/100)
What is the normal ratio of T cells to enterocytes in the duodenum?
Which part of polypeptides do trypsin, elastase and chymotrypsins act on?
Interior bonds of peptides
Whih hepatitis viruses are most easily transmitted through contaminated food?
A and E
Where is alcohol absorbed?
30% in stomach
70% in gut
What stimulates G cells to release gastrin?
Which cells make bile?
Where does the last part of carbohydrate digestion occur?
Disaccharidases and isomaltases at the brush border of mucosal enterocytes
In the classic lobule model of the liver, what is at the centre?
What hormone do enterochromaffin cells release?
Which enzyme conjugates bilirubin?
What does low hemopexin indicate?
What percentage of the liver's blood supply is from the portal vein?
Where are Peyer's patches found?
What does the allantois give rise to?
BLadder and urogenital tract
What is the main function of the muscularis mucosae layer of the GIT wall?
Mixing lumenal contents
How is fructose absorbed by enterocytes?
What would happen to a person without leptin receptors?
They would eat more and become obese
What is the average incubation period for HEV?
What percentage of the liver's oxygen supply is from the portal vein?
What type of epithelium is present in the gall bladder?
What do chief cells of the stomach produce?
Proteases eg pepsinogen
Broad spectrum antibiotics can cause overgrowth of what in the gut?
What does sessile mean?
A polyp that is not attached via a stalk
Where does fat digestion begin?
In the mouth with a lingual lipase
What is intrinsic factor essential for?
Absorption of VitB12
Where are monosaccharides absorbed?
Tips of villi in duodenum and jejunum
What does a rising IgG titre indicate in a viral hepatitis?
What % of gastric ulcers are due to Helicobacter pylori?
What percentage of energy is expended on basal metabolism?
What is fatty liver known as?
What are the side effects of magnesium hydroxide?
In dysentery caused by entamoeba histolytica, what will be noted in a stool sample sent for lab investigation?
Fewer bacteria, because ameoba eat bacteria
In which layer of the GIT are scattered immune cells found?
What is growth hormone release inhibitor better known as?
Diffuse nodules of regenerating hepatocytes surrounded by bands of fibrosis
What pathology is seen in acute viral hepatitis?
Lobular dissaray and apoptosis
What is the average incubation period for HBV?
What divides the functional/physiological right from left lobes of the liver?
Middle hepatic vein
Which cells synthesise leptin?
Where are colonic lymphatics?
In the submucosa
Does fat boy or skinny boy have a higher basal metabolic rate?
What is stage 4 chronic hepaptitis known as?
What are the 3 levels of anatomical structure that increase surface area in the small intestine?
Plica circulare, villi, microvilli
In what part of the stomach is pepsinogen II secreted?
Cose to pylorus
How is hepatitis C virus transmitted?
Percutaneous or permucosal
What is the problem in Crigler-Najjar syndrome?
Deficiency of UDP-glucuronyl transferase causes accumulation of toxic unconjugated bilirubin and kernicterus
What does low haptoglobin indicate?
By what stage of the GIT is digestion pretty much complete?
Half way along jejunum
Which zone of the acinar model is most vulnerable to ischaemia?
What is the most significant pathway for alcohol conversion to acetaldehyde?
What is the gold standard for diagnosis of coeliac disease?
Small bowel biopsy during gluten exposure
When does colon cancer become invasive?
When it breaches muscularis mucosae
What does pepsinogen do?
Hydrolyses bonds between an aromatic amino acid (phenylalanine and tyrosine) and another amino acid
What percentage of diarrhoea is due to viruses in developed countries?
How many mls of water are excreted per day in the faeces?
What do I cells of the GIT release?
What catalyses haem --> biliverdin?
What does pedunculated mean?
A polyp attached by a stalk
What do enterochromaffin cell-like cells release?
What are the pacemaker cells of rhythmic gut movement?
Interstitial cells of Cajal
What defines Marsh type 3 coeliac disease?
Villi are shortened and blunted: villous:crypt ratio is
What is/are the key histological feature/s of the duodenum?
Brunner's glands, fewer goblet cells
What effects does distension of the stomach have?
Activates stretch receptors --> vago-vagal reflexes --> acid and pepsin secretion Stretch --> hypothalamus --> decrease appetite
How does diarrhoea cause death in the delayed phase?
How big is a hepatic sinusoid?
0.7 x 2 mm
What shape are enterocytes?
Which receptors should be targetted for treatment of nausea associated with exposure to toxins?
D2 and 5-HT3
What is the most common familial colorectal cancer syndrome?
What type of nausea would a D2 antagonist be used to treat?
Which bacteria typically causes travelle's diarrhoea?
Enterotoxic E. coli (ETEC)
At what time point does hepatitis become chronic?
> 6 months
What are the important receptors for motion sickness/dizziness/vertigo associated nausea?
Muscarinic and H1
Where do HBV and HCV replicate?
In what form does hyperbilirubinaemia in the newborn cause neurotoxicity?
What type of drug is ranitidine?
In a hepatic sinusoid, what is the gap between endothelium and hepatocytes?
Space of Disse
What is the quality of diarrhoea of small intestine?
Infrequent or normal frequency, but much more watery with larger volumes
What's a good antibiotic for anaerobic organisms?
Which nerve mediates peristalsis along the esophagus?
Which parts of the GIT have serosa as their outer layer?
Parts of the gat not attached to anything --> secretes fluid to stop them sticking
How much water does the small intestine absorb per day?
In haemolysis, what is the intermediate product betwen haem and bilirubin?
How is a bile duct discriminated from a portal vein and hepatic artery on microscopy?
Bile duct has columnar epithelium
Which GIT cells secrete intrinsic factor?
Where is vitamin B12 absorbed?
What degree of amplification is achieved in the small intestine by the villi?
What % of gastric ulcers are due to NSAIDs?
What are the important receptors for the chemoreceptor trigger zone?
D2 and 5-HT3
How is hepatitis D virus transmitted?
Percutaneous or permucosal
Frequent stools of low volume would suggest what type of diarrhoea?
Diarrhoea of colon
Which hepatitis is most easily transmitted perinatally?
What is a rare but potential side effect of H2 antagonists?
What colour of soft drink/lolly will be be sweeter, even with the same amount of sugar?
How is entamoeba histolytica transmitted?
What causes damage to hepatocytes in viral hepatitis?
The immune response
What is achalasia?
Failure of smooth muscle of lower esophageal sphincter to relax causing dysphagia
What percentage of oxygenation does blood in the hepatic sinusoids contain?
What is a prebiotic?
A dietary supplement that promotes beneficial bacteria
Between which layers of the GIT wall are the myenteric ganglia?
Between circular layer and longitudinal layer of muscularis externa
Where do hepatitis viruses A and E replicate?
In hepatocytes and in intestinal epithelia
What causes the secretion of pancreatic lipolytic enzymes?
??? --> ROH + H2O + NADP+
RH + NADPH + H+ + O2 -->
What is the prevalence of coeliac disease?
Which enzyme breaks down alpha 1,6 bonds in polysaccharides?
How is giardia intestinalis transmitted?
Which cells in the GIT release somatostatin?
Which glands in the GIT secrete an alkaline mucous (mucous and bicarbonate) to neutralise acid from stomach?
What forms does conjugated bilirubin take?
Bilirubin mono-glucuronide and
Familial adenomatous polyposis is due to a mutation in which gene?
What does secretin trigger?
Secretion of bicarbonate rich solution from pancreas
What is colitis?
Inflammation of the bowel
What liver pathology does paracetemol toxicity cause?
Coagulative necrosis predominantly in zone 3
Which GI cells release gastrin?
Which cells proteases in the stomach?
What are 2 commonly used H1 antagonists for motion sickness?
Which nerve mediates the cephalic phase of digestion?
What is the antonym of mesenchymal?
What are the layers of the GIT?
1 Epithelium 2 Lamina propria 3 Muscularis mucosae 4 Submucosa 5 Muscularis externa - innter circular layer 6 Muscularis externa - longitudinal layer 7 Serosa/adventitia
What does the mesobephric duct become?
The vas deferens
How much water can the colon absorb in a day?
How is hepatitis A virus transmitted?
What % of pancreas is endocrine?
What do S cells of the GIT release?
What % of people infected with HCV will clear the virus?
What is/are the key histological feature/s of the ileum?
Peyer's patches, more goblet cells, shorter villi
What type of epithelium is present in the anal canal?
Stratified squamous, non-keratinised
How is chronic hepatitis graded?
Degree of interface inflammation
Which cells of the GIT release defensins?
How does enteropathogenic E. coli infect enterocytes?
It inserts Tir (translocated intimin receptor) into host cell via type 3 secretion. Tir is then expressed on host cell membrane. EPEC is then able to bind to Tir via intimin.
What will most labs do to investigate a faeces sample from a GI infection?
Microscopy and culture
What is the most effective treatment for recurrent C. difficile pseudomembranous colitis?
What do Harris-Benedict equations estimate?
What is/are the key histological difference/s between small intestine and large intestine?
Small intestine has villi; large intestine does not. Large intestine has more goblet cells
How does diarrhoea cause death in the acute phase?
Fluid and electrolyte imbalance
Through what does bile flow in liver lobules?
Through canaliculi to bile ducts
What are the most common classes of cause of unintentional weight loss?
How are most infections from toxoplasma gondii acquired?
What gives faeces its brown colour?
What inactivates pepsin?
Name 2 proton pump inhibitors
Omeprazole and esomeprazole
What is a probiotic?
A live organism that promotes health when ingested in sufficient quantities
Oral rehydration mixtures typically contain what?
NaCl, KCl, NaHCO3, glucose
What colour is urobilinogen?
What is the chief function of the muscularis externa in the GIT wall?
Movement of contents along gut
What % of the world is HCV positive?
What is ERCP?
Endoscopic retrograde cholangiopancreatography
How much alcohol is in a standard drink?
What effects does early-life exposure to hepatitis viruses have on clinical course?
Less severe acute infection and higher chance of chronic infection
What is the difference between a gastric erosion and acute gastric ulcer?
Erosion is limited to mucosa, whereas an acute ulcer penetrates into the submucosa
What are the 2 most common causes of steatosis?
Alcohol and obesity
Which immunoglobulin is most common in the gut?
What do D cells in the GIT release?
What degree of amplification is achieved in the small intestine by the folds of Kirkring?
Which hormone is released from the stomach in a fasted state and stimulates appetite?
What type of cells infiltrate in interface inflammation of chronic hepatitis?
How much water is excreted in faeces per day?
About 100 ml/day
What do we call the GI control systems that are activated prior to eating?
Cephalic phase of digestion
What are the three classes of anti-diarrhoeal agents?
Anti-motility. Anti-secretory. Binding agents.
What is the average incubation period for HAV?
Which pathogen typically causes antibiotic-associated diarrhoea?
Name 6 examples of when you would treat diarrhoea with antibiotics.
Cholera. Systemic infection. Immunocompromised. Severe shigella infections. Protazoal infections. Pseudomembranous colitis.
What percentage of absorption of products of digestion is done in the small intestine?
Which reflex mediates signals from the upper GIT that regulate upper GIT functions such as swallowing and acid secretions?
Which part of the villus is secretory in the small intestine?
RH + NADPH + H+ + O2 -->
ROH + H2O + NADP+
Are gut bacteria predominantly aerobic or anaerobic?
99.9% are anaerobic
What do we know about clostridium species?
How long does an acute HAV infection typically last?
Which organ is most commonly defective at birth?
Which protein transports conjugated bilirubin into the bile canaliculus?
cMOAT (aka MRP-2)
What is the problem in Dubin-Johnson disorder?
Genetic defect in cMOAT causes accumulation of non-toxic conjugated bilirubin
What is the most common form of hiatus hernia?
What changes to liver architecture may there by after extensive repair?
More fibrous and different lobular structure
What are the effects of gastrin?
Causes parietal cells to release acid
Blood, pus and mucous in faeces
What effect will injection of neuropeptide Y have on eating?
What is endangered with a fracture of the medial epicondyle of the elbow?
Define mesenchymal cells
Cells that lost contact with each other
and move independently and alone
Injecting cocaine and amphetamine regulated transcirpt (CART) will have what effect on eating?
What is the most common genetic mutation that can cause obesity?
Melanocortin 4 receptor
How do proton pump inhibitors work?
Irreversible inhibition of H+/K+ ATP ase
How do prostaglandins protect the mucosa from injury?
Promote HCO3- secretion, inhibit acid secretion, maintain blood flow
What is gastrophoresis?
Delayed gastric emptying
Define coeliac disease
Immunologically mediated disease... in genetically susceptible individuals... driven by gluten... which results in chronic inflammation... of the small bowel mucosa
What blood test is indicative of acute HBV infection?
What is a very common non-human host of giardia intestinalis in Australia?
What % of duodenal ulcers are due to Helicobacter pylori?
What are the most common pathogenic agents in dysentery?
Enteroinvasive E. coli/Shigella Entamoeba histolytica
Which hepatitis viruses tend to cause chronic disease?
HBV and HCV
What effects does CCK cause as a hormone?
Contractions of gall bladder to force bile down into duodenum. Releases digestive enzymes from pancreas. Stimulates satiety centre in hypothalamus
How can you distinguish an artery from its partner vein?
Usually smaller and more tortuous
All derivatives of endoderm are _______
What catalyses acetaldehyde --> acetate
What happens to goblet cell frequency along the course of the GIT?
What are the side effects of sodium bicarbonate?
What is the most commonly used H2 antagonist?
What will be seen in the stool of an invasive diarrhoea?
Blood and pus
Blood, but not pus, in diarrhoea suggests which organism?
Enterohaemorrhagic E. coli
_______ consists of an open chain of four pyrrole rings
What happens with withdrawal of antacids?
Where is alanine transferase located?
Cytoplasm of hepatocytes
What is the most common cause of liver cancer?
What is the gold standard for measuring energy expenditure?
Double labeled water (Deuterium/oxygen 18)
How do antacids work?
Neutralise stomach acid
What activates cholesterol esterase?
What catalyses trypsinogen --> trypsin?
Enterokinase and trypsin
What is the role of smooth ER in hepatocytes?
Fat and steriod metabolism
What effects does somatostain have in the GIT?
Inhibits histamine release from enterochromaffin cell-like cells Inhibits HCl release from parietal cells
Bilirubin consists of an open chain of _______
four pyrrole rings
What do we call a fertilized ovum?
What are the American (more stringent) criteria for Barrett's esophagus?
Evidence of columnar epithelial lining in esophagus; AND
Evidence of goblet cells in esophagus
What is the function of paneth cells?
Secrete anti-microbial peptides (defensins)
What do paneth cells release?
What is the average incubation period for HCV?
Which germ layer does the epithelium of the gut come from?
How is hepatitis B virus transmitted?
Percutaneous or permucosal
Elevated ALT levels in hepatitis indicate what?
What percentage of faeces is bacteria?
Inflammation around the portal tract is known as what?
What would happen to energy intake if all microbiota were removed from a person?
Energy intake would need to increase
Which enzyme activates IL-1?
IL-1 converting enzyme (ICE) aka caspase 1
Which cells of the GIT release cholecystokinin?
What is the pathological hallmark feature of steatohepatitis?
Hepatocellular ballooning degeneration
Where does pinworm live?
Pharmacologically, what are the two most important inputs to the vomit centre?
Chemoreceptor trigger zone (CTZ)
Which protease acts at the carboxy terminals of peptides?
What is koilocytosis?
A ring around nucleus
What is the defining feature of enterohaemorrhagic E. coli?
It produces shigatoxin
Barrett's esophagus infers what relative risk for esophageal adenocarcinoma?
Particularly offensive smelling diarrhoea stool suggest what type of organism?
What is a commonly used antimuscarinic drug for motion sickness?
What is the largest internal organ?
Where do central veins drain to?
Which enteroendocrine cells release serotonin?
What type(s) of collagen are found in the liver?
1 and 3
What type of epithelium is present in the small intestine?
Cilliated simple columnar
What is the pathogen in cholera?
What is the last macronutrient to pass through the pylorus after a meal?
How much alcohol can a person typically clear in 1 hour?
1 standard drink = 0.015% BAC = 10 g alcohol
What stimulates D cells to release somatostatin?
What effects do artificial sweeteners have on GI activity?
Bind to L cell receptors to increase glucose absorption
What is the quality of diarrhoea of colon?
Frequent stools of low volume
How much water does the colon absorb per day?
What are the extra-intestinal complications of entamoeba histolytica?
Liver or brain abscesses
How do goblet cells contribute to immunity?
Secrete mucins, lysozyme and lactoferrin
With sustained alcohol intake, what is induced to high levels and provides an alternative pathway for EtOH metabolism?
CYP2E1 aka MEOS Microsomal Ethanol Oxidising System
What colout is bile?
Dark green to yellowish brown
How much bile can the human liver produce per day?
Close to 1 litre per day
What is family of molecules, composed of a steroid structure with four rings, a five or eight carbon side-chain terminating in a carboxylic acid?
What are the most important bile acids in humans?
Cholic acid, deoxycholic acid, and chenodeoxycholic acid
What percentage of bile salts are reasorbed and were are they reasbosrbed?
95% are reabsorbe din the terminal ileum
Which hormones regulate pancreatic juice secretion?
Secretin and cholecystokinin
Which cells of the pancreas secrete bicarbonate?
Which cells of the pancreas produce digestive enzymes?
What is the predominant component of bile?
Which 3 substances can trigger exocrine secretions from the pancreas?
ACh (from vagus), CCK and secretin
What activates pancreatic lipase?
Nodules of regenerating hepatocytes surrounded by bands of fibrosis tissue
Which hepatitis viruses can cause cirrhosis?
B and C
Which chronic liver diseases can lead to cirrhosis?
All of them
Which cells are stimulated to cause fibrosis in cirrhosis?
What is a potential consequence of splenomegaly in cirrhosis?
What is the most common cause of portal hypertension?
How is portal hypertension defined?
Increase of >8mmHg in the portal vein
Increase of >5mmHg in pressure gradient between portal vein and hepatic vein
What are the 3 cardinal consequences of portal hypertension?
Splenic enlargment. Ascites. Varices at sites of porto-systemic anastamoses
What are the 3 main points of anastomosis between the portal and systemic venous systems?
Esophagus. Rectum. Umbilicus
Which liver enzymes are located in hepatocyte cytoplasm?
AST, ALT, LD
Which liver enzymes are associated with the biliary membrane?
GGT and ALP
Which enzyes are released with hepatocellular damage?
AST and ALT
Is ALT or AST more specific to liver damage?
Where is ALT present?
Cytosol of hepatocytes
Where is AST present?
Cytosol and mitochondria of liver, muscle and blood cells
What is suggested if AST > ALT?
Acute liver damage
What is suggested if ALT > AST?
Chronic or resolving liver damage
Which of AST and ALT has a longer half life?
What does elevated GGT levels suggest?
What is the most common cause of raised liver enzymes?
Pain from an ulcer in the duodenum is made _______ with eating
Pain from an ulcer in the stomach is made _______ with eating