Anatomy of GI tract bleeding Flashcards
Is the caecum intraperitoneal or retroperitoneal?
intraperitoneal
so quite mobile
Is the ascending colon intraperitoneal or retroperitoneal?
secondary retroperitoneal
Is the transverse colon intraperitoneal or retroperitoneal?
intraperitoneal
- highly movable, has its own mesentery
Is the descending colon intraperitoneal or retroperitoneal?
secondary retroperitoneal
Is the sigmoid colon intraperitoneal or retroperitoneal?
intraperitoneal
- has its own mesentery
Where are the pancreatic gutters found?
between lateral edge of ascending and descending colon, and abdominal wall
One on the right and left
What can commonly collect in pancreatic gutters?
pus
What are three distinguishing features of the colon?
Omental appendices
Teniae coli
Haustra
What is the role of the teniae coli? What are they?
Facilitate the movement of faeces through the intestine
3 distinct longitudinal bands of thickened smooth muscle, running from caecum to distal end of sigmoid colon
Come together at the appendix
Which two flextures are part of the large instestine?
splenic - higher up
hepatic
What are ommental appendices?
small, fatty projections
What is the most common position of the appendix?
retrocaecal
Where do the Caecum and appendix lie?
right illiac fossa
What connects the ileum and the caecum?
Ileocaecal orifice
What connects the caecum and the appendix?
Appendiceal orifice
Where does the sigmoid colon lie?
left iliac fossa
What is it called when the sigmoid colon twists around itself?
Sigmoid volvulus
- due to its very flexible mesentery
- results in bowel obstruction
- congeital or acquired
What occurs at L4?
aorta bifurcates into the common iliac artery
where the top of the iliac crest
What are the 3 midline branches of the abdominal aorta?
Celiac trunk (foregut organs)
Superior mesenteric artery (midgut organs)
Inferior mesenteric artery (hindgut organs)
What is the difference between the ileum and jejunums vasculature?
Jejunum
- Longer vasa rectae
- Larger and fewer arcades
Ileum
- Shorter vasa rectae
- Smaller and many arcades
What is the marginal artery of drummond?
arterial anastomoses between the branches of the SMA and the IMA
What is the blood supply to the rectum and anal canal?
Superior rectal artery, a branch of IMA
What supplies the rest of the GI tract? (apart from the rectum and anal canal)
internal iliac artery
What is the funciton of the hepatic venous system?
Drains venous blood from absorptive parts of the GI tract & associated organs to the liver for ‘cleaning’
What happens when portal veins are blocked?
portal hypertension
What drains foregut structures to the hepatic portal vein?
splenic vein
What drains midgut structures to the hepatic portal vein?
Superior mesenteric vein
What drains hindgut structures to the hepatic portal vein?
Inferior mesenteric vein
What are the 3 clinically important sites of venous anastomosis between the systemic and the portal venous systems?
The skin around the umbilicus
Distal end of oesophagus
Rectum/Anal canal
Describe the astamoses for the skin around the umbilicus?
Connection between para-umbilical veins and small epigastric veins
Para-umbilical veins to hepatic portal vein along the round ligament of liver
Epigastric veins drain to caval system
Describe the astamoses for the distal end of the oesophagus?
Inferior part drains to the hepatic portal vein
Superior part drains to the azygous vein
Describe the astamoses for the rectum/anal canal?
Rectum and superior anal canal drains to inferior mesenteric vein
Inferior part of GI tract drains to the internal iliac veins
What is portal hypertension? What causes it?
Elevation of blood pressure in the portal system
Can be caused by;
Liver pathology (cirrhosis)
Tumour compressing HPV
What are the clinical signs of portal hypertension?
Oesophageal varices
Caput medusa
Rectal varices
What is haematemesis?
vomiting up blood
