Lecture 13-Large Intestine Flashcards
True or false: the LI has villi
FALSE
What are the three distinct bands in the external longitudinal muscle of the LI called?
Teniae coli
What are haustra?
Sacculations caused by the contraction of teniae coli (like a drawstring)
What are the functions of the LI?
- removes water from indigestible contents
- turns chyme into semi-solid
- produces vitamin K
- acts as a temporary store until defecation
- water absorption in ascending and part of transverse colon
- rest of transverse and descending colon for temporary storage
How does water absorption occur in the colon?
- facilitated by ENaC
- induced by aldosterone
What is the gastro-colic reflex?
Rapid peristalsis in the distal colon into the rectum
How does Crohn’s disease present?
- affects anywhere in GI tract, mainly ileum
- transmural (through wall)
- skip lesions
- weight loss
- loose stools
- RLQ pain
- joint pain
- mild perianal inflammation/ulceration
- low grade fever
- mildly anaemic
How does Ulcerative Colitis (UC) present?
- confined to colon
- continuous pattern
- confined to mucosa
- weight loss
- blood stools with mucus
- mild lower abdominal pain
- painful red eye
- no perianal disease
What are some extra-intestinal problems that can occur in inflammatory bowel disease?
- MSK pain
- skin - psoriasis, erythema
- liver/biliary tree problems
- eye problems
How can Crohn’s disease and UC be investigated?
- bloods
- CT/MRI
- barium enema
- colonoscopy
- stool culture (UC)
What are some gross changes that occur in Crohn’s?
- hyperaemia (red, angry vessels)
- mucosal oedema
- deep ulcers
- inflammation deeper than mucosa -> fistula
- cobblestone appearance
What are some gross changes that occur in UC?
- inflammatory infiltrate of lamina propria
- crypt abscesses
- pseudopolyps (regenerating mucosa)
- loss of haustra
Which IBD presents with granulomas microscopically?
Crohn’s
What is the medical approach to treating IBD?
- aminosalicyclates for flares and remission
- corticosteroids for flares only
- immunomodulators for fistulae/maintenance of remission
Why is surgery not the best treatment for Crohn’s?
Can lead to adhesions -> abdominal pain
