Anatomy of GI bleeding Flashcards Preview

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Flashcards in Anatomy of GI bleeding Deck (24):

What is the function of the large intestine 

  • Defence againt commensal bacteria 
  • Absorption - H2O and electrolytes 
  • Excretion of formed stool 


Describe the anatomy of the colon

  • Caecum, appendix, Ascending, transverse, Descending, Sigmoid
  • Location: inferior to liver and Spleen 
  • From Caecum to sigmoid: intraperitoneal - Secondarily retroperitoneal - intraperitoneal - secondarily retroperitoneal - intraperitoneal 

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What are Paracolic gutter 

  • Spaces between the colon and the abdominal wall 
  • peritoneal recesses on the posterior abdominal wall lateral to the ascending and descending colon respectively. 


Describe the anatomy of the paracolic gutters

  • Left and right paracolic gutters
  • Between lateral edge of the ascending and descening colon 
  • Postential sites for pus collection 

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What are the features of the colon 

  1. Omental appendices
  2. Teniae coli - 3 longitudinal bands of thick SM
  • Runing from the caecum once the come together at the appendix to the distal end of the sigmoid colon

    3.    Haustra - Sacculations cause by the contractions to teniae coli 

  • Gives rise to the segmented appearance on colon 

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How does the colon look like one radiological appearance 

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describe the anatomy of the caecum and the appendix

  • location = both in right iliac fossa 
  • postion of appendix is variable - but most commonly rectrocaecal 
  • Appendiceal orifice - posteriomedial wall of caecum - Mcbuney's point on anterior abdominal wall 

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What is the Mcburney's point and wheres its location 

  • Where the appendiceal orifice is found
  • 1/3rd of the way between Right Asis to umbilicus
  • Maximum tenderness when appendicitis 

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What is the anatomy of the sigmoid colon 

  • Location - Left iliac fossa 
  • Has a long mesentery - Sigmoid mesocolon - significant degree of movement 
  • Disadvantage of long mesentery - Risk of Twisting around itself - Sigmoid volvulus 
  • Results in bowel obstruction
  • Bowel at risk of infarction 

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What is the anatomy of the abdominal aorta 

  • Midline Retroperitoneal structure 
  • lies to left of IVC 
  • 3 Midline branches - celiac trunk, SMA and IMA
  • Lateral branches- renal, gonads and body wall 
  • Common illiac bifurcation - internal and external 

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What are all the levels of the abdominal aorta bifurcation 

  • SMA - L1 
  • IMA - L3 
  • Celiac trunk - T12 
  • Common illiac bifurcation - L4 

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What are all the branches of the SMA

  • Inferior pancreaticodoudenal
  • Middle colic artery 
  • Right colic artery
  • ileocolic artery
  • Appendicular 
  • Jejunal and ileal arteries 

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Describe the anatomy of Jejunal and ileal arteries 

There both have a wasa rectae and arterial arcades 

  • Jejunum has longer vasa rectae and larger but  fewer arcades
  • Ileum has a shorter wasa resctae and small and many arcades

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What are the branches of the IMA 

  • Left Colic artery 
  • Sidmoid arteries
  • Superior rectal arteries 

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what is the marginal artery of drummond 

Arterial anatomoses between the Branches of the superior mesenteric artery and inferior mesenteric artery - obstruction in these vessels can help prevent intestinal ischaemia 

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what do the IMA and SMA look like on imaging 

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What is the blood supply to the rectum and anal cana;

  • Rectum - Superior rectal artery - branch of IMA
  • Below pectinate line = internal illiac 


Describe the 2 veous system in the body 

  • Hepatic portal venous system - Drains venous blood from absorptive parts of GI tract into liver for cleaning
  • Systemic venous system - Drains all other parts of organs and tissue into SVC or IVC 

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What is the heptic porta vein made up on 

Spleenic vein (foregut) and Superior mesenteric vein (Midgut Structures) 

  • Inferior mesenteric vein (hindgut) drains into the spleenic vein 

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Where are the important portal-system anastomosis

  • Skin around umbilicus - Connect para-umbilical veins and Epigastric veins 
  • Rectum/anal canal - Inferior into iliac veins superior into IMV
  • Distal end of Eosophagus - inferior part drains into Hepatic portal vein and Superior part drains into azygous vein

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Venous drainage from the rectum and anal canal 

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What is Portal hypertension

  • Hypertension of the HPV - due to Cirrhosis or Tumour compressing HPV 
  • Leads to reversal of blood flow 
  • Larger volume of blood to these areas can cause them to become varicosed 

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Clinical presentation of portal hypertension 

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What can the source of Haematemesis be 

  • peptic ulcer in wall of stomach 
  • Oesophageal varices