Pathoma: Colon (1) Flashcards
The disease that presents with defective peristalsis and relaxation of the rectum is associated with what congenital disorder?
Down syndrome (the disease described is Hirschsprung’s)
True or false: you need Meissner’s plexus for peristalsis.
False. Meissner’s plexus (also called the submucosal plexus) is involved in secretion of mucus and regulation of blood flow. Auerbach’s plexus in the muscularis propria controls peristalsis.
Why is a suction biopsy necessary for a diagnosis of Hirschsprung’s?
Because in a normal biopsy you only get the mucosa. You need to suction to suck up deeper layers and see if there are enteric ganglia present.
Which layers get pushed out in diverticula?
Mucosa and submucosa push through the muscularis propria
The most common location for diverticula is __________.
the sigmoid (typically where vasa recta pass through the muscularis propria)
Three things can result from diverticula: ________________.
- hematochezia
- fistula (between the bladder or anything)
- diverticulitis
What is angiodysplasia?
An acquired malformation of the mucosal and submucosal capillary bed; induced by stress; often occurs on the right side and can lead to hematochezia
_____________ leads to dilation of thin-walled blood vessels throughout the GI tract.
Hereditary hemorrhagic telangiectasia
The most common cause of ischemic colitis is _____________.
atherosclerosis of the superior mesenteric artery
______________ pain improves with defecation.
Irritable bowel syndrome
Polyps are raised ______________.
colonic mucosa
The most common type of colonic polyp has a ___________ appearance on microscopy and usually arises in the ____________ colon. What malignant potential does it have?
serrated; left; none (this is hyperplastic polyp)
______________ polyps are premalignant.
Adenomatous
APC mutation by itself does not induce malignant transformation. However, combined with _________ mutations, a polyp will form. Lastly, ___________ and __________ mutations can lead to malignancy.
KRAS; p53; increased COX
Why is aspirin protective against colon cancer?
Cyclooxygenase production is usually necessary in the most common adenoma-carcinoma sequence, so inhibiting COX with aspirin (irreversibly) slows progression.
