Small and large intestines Flashcards
What kind of epithelium are in the large intestine?
Columnar epithelium
What are the functions of the large intestine?
Removes water from all indigestible gut contents which turns chyme into a semi solid Produces vitamins Acts as temporary storage until defecation occurs
Is the large intestine shorter and wider than the small intestine?
Yes
Why is large intestine more flat?
Don’t need the large surface area as not absorbing as much
How does large intestine remove water?
Facilitated by ENaC and induced by aldosterone open channels getting sodium into the cell so gradient
How do things move from colon to rectum?
Peristalsis first in a liquid state and then in a solid state Mass movement Empties stool from sigmoid colon into the rectum Sphincters relax and rectum contracts Disposing its contents
What is the mechanism of defecation?
The rectum is innervated by nerves that initiate the reflex contractions External anal sphincter and internal anal sphincter Internal- sympathetic nerve excites, parasympathetic nerve inhibits Relaxes when being distended External- skeletal muscle so innervated by pudendal nerve this is maintained in a state of contraction At a pressure of 18mmHg the need to defecate occurs and is voluntary through straining, at 55mmHg it is uncontrollable
What does the most water absorption large of small intestine?
Small intestine- may be large intestines main function but doesn’t mean it absorbs more- just the last part
What are the causes of intestinal inflammation and infection?
Inflammatory bowel disease Chrohns disease Ulcerative colitis Group of conditions characterized by idiopathic inflammation of the GI tract Affects function of gut
What is the clinical presntation of crohns disease?
lots of stools, non bloody, weight loss, right lower quadrant pain, some joint pain, smoker, tender mass, mild perianal inflammation, low grade fever, mildly anaemic
Where does crowns disease affect?
Affects anywhere in the GI tract, Ileum involved in most cases Ileum involved in most cases Transmural and skip lesions
Where does crohns disease affect?
Affects anywhere in the GI tract, Ileum involved in most cases Ileum involved in most cases Transmural and skip lesions
What is the clinical presentations of ulcerative colitis?
Bloody stools, mucus in stools, weight loss, mild lower abdominal pain/cramping, painful eye, mild tender abdomen, no perianal disease, normal temp
Where does ulcerative colitis affect?
Begins in the rectum Can extend to involve entire colon Continuous pattern Mucosal inflammation
What is used to investigate Crohns?
Bloods will have anaemia CT and MRI will have bowel wall thickening obstruction and extramural problems may do barium enema which may see fistulae or strictures colonoscopy
What is used to investigate ulcerative colitis?
Bloods will have anaemia and serum markers stool culture plan abdomen radiographs barium enema in mild cases colonoscopy
What is the gross pathology of crohns?
hyperamia mucosal oedema discrete superficial ulcers deeper ulcers transmural inflammation- thickening of bowel wall and narrowing lumen cobblestone appearance fistulae
What is the microscopic pathology of crohns?
Granulomas
What is the pathology of ulcerative colitis?
Chronic inflammatory infiltrate lamina propria crypt abscesses goblet cells Pseudopolyps Loss of haustra crypt abscesses
What does Crohns disease usually have that Ulcerative colitis doesn’t have?
Transmurral inflammation- deeper and goes through the wall Granulomas Fibrosis Skip lesions Ulcers Cobblestone appearance Narrowing Perianal disease Fistula
What does Ulcerative colitis have that crohns disease does not?
Crypt abscesses Continuous Friable mucosa Rectal involvement gross bleeding can become cancer
What is the treatment for inflammatory bowel disease?
Aminosalicycyclates For flares and remission Corticosteroids For flares Immunomodulators Fistulas/maintenance of remission
What inflammatory bowel disease is curable?
Ulcerative colitis
What are the main points of the Crohns disease?
Transmural Skip lesions Strictures and fistulas
