The colon Flashcards
which parts of the colon are
1) mobile
2) immobile
1) mobile
- ceacum (intraperitoneal) = quite mobile
- transverse colon = very mobile
- sigmoid colon = quite mobile
what are paracolic gutters
They are spaces between the colon and the abdominal wall. They are potential sites of pus collection
what are taeniae coli
3 distinct longitudinal bands of smooth muscle, running from caecum to distil end of sigmoid colon
where does the caecum and appendix normally lie
Both lie in the right iliac fossa
where does the sigmoid colon lie
lies in the left iliac fossa
what does the pancreas lie posterior to
stomach
what does the pancreas have
- head (with uncinate process)
- neck
- body
- tail
what type of a structure is the abdominal aorta
midline retroperitneal structure and anterior to the vertebral bodies
what are the 3 midline branches
- celiac truck = foregut organs
- superior mesenteric artery = midgut organs
- inferior mesenteric artery = hindgut
what are the branches of the superior mesenteric artery
- inferior pancreaticoduodenal
- middle colic
- right colic
- ileocolic
- appendicular
- jejunal and ileal
what are the branches of the inferior mesenteric artery
- left colic
- sigmoid colic
- superior rectal
what is the relevance of the arterial anastomoses between the superior mesenteric artery and the inferior mesenteric artery
Forms predominantly one artery called the marginal artery of Drummond. Collateral blood supply means structures towards the end of the colon can still get blood supply
what is haematemesis
vomiting blood
what are the 2 main venous systems of the body
- hepatic portal venous system - drains venous blood from absorptive parts of the GI tract and associated organs to the liver for cleaning
- systemic venous system - drains venous blood from all other organs and tissues into the superior or inferior vena cava
where does the inferior mesenteric vein drain blood
Drains blood from the hindgut structures to the splenic vein
where does the superior mesenteric vein drain blood
Drains blood from the midgut structures to hepatic portal vein
where does the splenic vein drain blood
Drains blood from foregut structures to hepatic portal vein
where does the hepatic portal vein drain blood
Drains blood from foregut, midgut and hindgut structures to the liver for first pass metabolism (cleaned)
where does the inferior vena cava (retroperitoneal) drain blood
Drains cleaned blood from the hepatic veins into the right atrium
what is the function of portal systemic anastomoses
at these sites the presence of small collateral veins means blood can flow both ways
where are the 3 portal systemic anastomoses
- distil end of oesophagus
- skin around umbilicus
- rectum/anal canal
what are clinical presentations of portal hypertension
- oesophageal varices
- “caput medusae”
- rectal varices
what are the 2 main types of idiopathic inflammatory bowel disease
Crohn’s disease and Ulcerative Colitis
what is Crohn’s disease
Chronic inflammatory and ulcerating condition of the GI tract that can affect anywhere from the mouth to the anus.
Most common in the terminal ileum and colon
what are the sites for Crohns
- 2/3 have small bowel involvement only
- 1/6 have colonic/anal disease only
- 1/6 have both
how does Crohns disease present
- abdominal pain
- small bowel obstruction
- diarrhoea
- bleeding PR
- anaemia
- weight loss
what is seen microscopically in Crohns disease
- chronic active colitis with granuloma formation
- increased chronic inflammatory cells in the lamia propria and crypt branching with granulomas
- large non-caseating granulomas
- patchy chronic active colitis
inflammation involves all layers of the wall