Pathology of Colon Flashcards
what is the role of the small bowel
absorptive role
what is the role of the large bowel
absorptive and secretory role
what is the small intestine divided into?
duodenum, jejunum and ileum
what is the large intestine divided into?
Caecum
Ascending colon-retroperitoneal
Transverse colon
Descending colon-retroperitoneal
Sigmoid –originates pelvic brim
Rectum-15cm, distal 7cm
extraperitonealsmall intestine histology
Mucosa: innumerable villi 3 cell types Goblet cells Columnar absorptive cells Endocrine cells Crypts: stem, goblet, endocrine and Paneth Lamina propria, muscularis mucosa, submucosa, Muscularis propria and subserosa Renewed every 4-6 days
large intestine histology
Flat –no villi
Tubular crypts
Surface-columnar absorptive cells
Crypts-goblet cells, endocrine cells, stem cells turnover 3-8 days
what does dysfunction of the intestinal immune system cause?
chronic disease
life threatening acute conditions
what is the small and large bowel peristalsis mediated by?
intrinsic (myenteric plexus) and extrinsic (autonomic innervation) neural control
where is the meisseners plexus located?
base of the submucosa
where is the auerbach plexus located?
between the inner circular and outer longitudinal layers of the muscuularis propria
what causes inflammatory bowel disease?
Ulcerative colitis Crohn’s disease Ischaemic colitis Radiation colitis Appendicitis
what is idiopathic inflammatory bowel disease?
Chronic inflammatory conditions resulting from inappropriate and persistent activation of the mucosal immune system driven by the presence of normal intraluminal flora
what are the two main diseases of idiopathic inflammatory bowel disease?
crohns disease
ulcerative colitis
where does crohns disease effect you
any part of the GIT from the mouth to the anus
where does ulcerative colitis effect you?
limited to the colon
what is aetiology of inflammatory bowel disease?
Strong immune response against normal flora with defects in the epithelial barrier function in genetically susceptible individuals
what antibody to people with IBD posses?
pANCA
who is more liley to get ulcerative colitis
male, 20-30 and 70-80 years
UC pathology
Large bowel only Continuous pattern of inflammation. Rectum to proximal Pseudopolyps Ulceration Serosal surface minimal or no inflammation
complications of UC?
Haemorrhage
Perforation
Toxic dilatation
who is more likely to get crohns disease?
females, 20-30 and 60-70
CD pathology
Granular serosa / dull grey
Wrapping mesenteric fat
Mesentry- thickened, oedematous and fibrotic
Wall thick, oedematous
Narrowing of lumen
Sharp demarcation of disease segments from adjacent normal tissue “skip lesions”
Ulceration- “cobblestone”
UC histology
no granulomas
CD histology
non-caseating granulomas
