36 - GI System IV Flashcards
(95 cards)
What is colonic diverticula?
A “pouching out” of mucosa and submucosa that is found in the large intestine at a site of weakness between tinea coli
Why would we only see colonic diverticula in the large intestine and not in the rectum?
Because the rectum has a complete and continuous muscularis externae (no sites of weakness)
What areas of the large intestine are even more susceptible to colonic diverticula?
Sites where blood vessels and nerves penetrate
Is a colonic diverticula a true diverticula or a false diverticula? Why?
A false diverticula because a true diverticula would include all layers of the wall whereas a colonic diverticula only involves the mucosa and submucosa
What portion of the intestines do we commonly see polyps?
Large intestine
What procedure allows us to see polyps of the GI tract?
Colonoscopy procedure via a colonoscope
Are polyps usually removed when they are found or are they usually left?
Usually removed
Why do polyps develop in the first place?
Due to the hyperproliferation of cells
What are the two types of polyps we see?
- Tubular adenoma
- Villous adenoma
Note that sometimes we see a mix between the two types
Which type of polyp is more invasive?
Villous adenoma
Is the size of the polyp clinically relevant?
Yes - the larger the polyp, the more likely it is to be invasive
Which statement regarding lymphatic vessels in the lamina propria of the large intestine is true?
a. Is well endowed with lymphatic vessels
b. Is poorly developed
c. Is better developed in the presence of inflammatory bowel disease
a. Is well endowed with lymphatic vessels = FALSE
b. Is poorly developed = TRUE
c. Is better developed in the presence of inflammatory bowel disease = TRUE
Why is there an increased density of lymphatic vessels in inflammatory bowel disease?
This is a compensatory response to the inflammatory edema that exists
What are some tissue modifications that you will see in inflammatory bowel disease?
- The architecture of the wall will be modified
- Lamina propria will be full of dark blue inflammatory cells
- The lamina propria will contain an increase density of lymphatic vessels
What are the two major forms of inflammatory bowel disease?
- Ulcerative Colitis
- Crohn’s Disease
Where is ulcerative colitis typically found?
Confined to the large intestine
Where is Crohn’s disease typically found?
Anywhere along the GI tract
Which form of inflammatory bowel disease is more likely to form fissures and fistulas that invade neighboring organs?
Crohn’s disease - because it is found anywhere along the GI tract
What is the difference between a fissure and a fistula?
A fissure will open into the peritoneal cavity and leak the intestinal contents into this space
A fistula will open into a neighboring organ and leak the intestinal contents into this organ
What is Hirschsprung’s disease?
AKA congenital megacolon
- A condition caused by neural crest cells failing to properly migrate into the affected segment of the colon
- The result is that there will be a lack of both plexuses in that segment of the colon (myenteric and submucosal plexuses)
What does the lack of plexuses in Hirschprung’s disease lead to?
The area lacking the plexuses will remain constricted, which causes the proximal area to dilate (megacolon) in order to compensate for the damming effect
What areas of the colon are involved?
The rectum is ALWAYS involved and the more proximal segments may also be involved
Case study: patient has difficult/painful swallowing for 3 years and a long history of irritable bowel syndrome - a CT scan shows a large thickening of the esophagus explaining the swallowing problems… What is this from?
A fissure that extends into the submucosa of the esophagus - the fissure as well as the endoscopy and biopsy are indicative of Crohn’s disease
What is the capsule that surrounds the liver called?
Glisson’s capsule