GI Flashcards
Which cells of the GIT release secretin?
S cells
What is a normal ratio of villus height to crypt depth?
4:1
What degree of amplification is achieved in the small intestine by the microvilli?
600
What effect does caesarian section have on microbiota?
Restricts microbiota diversity
What caues pancreatic release of alpha amylase?
Cholecystokinin
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?
Mesoderm
What do the names of proton pump imhibitors end with?
-prazole
Which drugs were used to treat peptic ulcers before PPIs were invented?
H2 antagonists
What is magnesium hydroxide used to treat?
Antacid treatment
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?
Kupfer cells
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?
50-60%
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?
Macrovesicular
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?
18%
Where does human papiloma virus like to infect?
Basal keratinocytes of transformational zone of cervix
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What is the hallmark pathological feature of acute and chronic viral hepatitis?<!--EndFragment-->
Apoptosis
What must be produced to cause haemolytic-uremic syndrome?
Shiga toxin aka verotoxin
Which intestinal lumenal transporter is inactivated during diarrhoea?
Na/Cl co-transporter
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?
All parts
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?
Gastrin
What do we call delayed gastric emptying?
Gastrophoresis
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?
3%
In the portal lobule model of the liver, what is at the centre?
Portal triad
Which hepatitis viruses have a vaccine?
A, B and D
How is HAV excreted?
In faeces
What colour is bilirubin?
Yellow
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?
HCV
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?
Norther Territory
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Where do hepatic sinusoids drain?
Central vein
What do parietal cells of the stomach produce?
HCl and intrinsic factor
What % of people with long-standing GORD develop Barrett’s oesophagus?
5-8%
How is hepatitis E virus transmitted?
Faecal-oral
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?
Parietal cells
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
Metoclopramide (maxolon)
Prochlorperazine (stemetil)
What is kernicterus?
Bilirubin-induced brain dysfunction
What is a councilman body?
Apoptotic hepatocyte
How is acute hepatitis defined in terms of blood tests?
Raised ALT < 6 months
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What gives urine its yellow colour?
Urobilin
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?
Villus
What defines Marsh type 2 coeliac disease?
Crypts enlarge
What drug is a systemic antacid?
Sodium bicarbonate
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?
300-400%
What catalyses biliverdin –> bilirubin?
Biliverdin reductase
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?
Zone 3
What is the main form of cell death in chronic hepatitis?
Apoptosis
In regulation of eating, the arcuate nucleus of the hypothalamus projects to which other hypothalamic areas?
Paraventricular nuc.
Lateral hypothalamus
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?
0.015%
How is glucose absorbed by enterocytes?
SGLT1 Sodium-dependent glucose trasnporter 1
What is the lifespan of a hepatocyte?
150 days
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?
1:4
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?
Amino acids
Which cells make bile?
Hepatocytes
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?
Central vein
What hormone do enterochromaffin cells release?
Serotonin
Which enzyme conjugates bilirubin?
Glucuronyl transferase
What does low hemopexin indicate?
Haemolytic anaemia
What percentage of the liver’s blood supply is from the portal vein?
75%
Where are Peyer’s patches found?
Ileum
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?
GLUT5
What would happen to a person without leptin receptors?
They would eat more and become obese
What is the average incubation period for HEV?
40 days
What percentage of the liver’s oxygen supply is from the portal vein?
50%
What type of epithelium is present in the gall bladder?
Simple columnar
What do chief cells of the stomach produce?
Proteases eg pepsinogen
Broad spectrum antibiotics can cause overgrowth of what in the gut?
Clostridium difficile
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?
Acute infection
What % of gastric ulcers are due to Helicobacter pylori?
70%
What percentage of energy is expended on basal metabolism?
65-75%
What is fatty liver known as?
Steatosis
What are the side effects of magnesium hydroxide?
Diarrhoea
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?
Lamina propria
What is growth hormone release inhibitor better known as?
Ghrelin
Define cirrhosis
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?
60-90 days
What divides the functional/physiological right from left lobes of the liver?
Middle hepatic vein
Which cells synthesise leptin?
Adipocytes
Where are colonic lymphatics?
In the submucosa
Does fat boy or skinny boy have a higher basal metabolic rate?
Fat boy
What is stage 4 chronic hepaptitis known as?
Cirrhosis
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?
Haemolytic anaemia
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?
Zone 3
What is the most significant pathway for alcohol conversion to acetaldehyde?
Alcohol dehydrogenase
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?
40%
How many mls of water are excreted per day in the faeces?
100ml
What do I cells of the GIT release?
Cholecystokinin
What catalyses haem –> biliverdin?
Haem oxygenase
What does pedunculated mean?
A polyp attached by a stalk
What do enterochromaffin cell-like cells release?
Histamine
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?
Malnutrition
