5. Histology of the Small and Large Intestine Flashcards
What glands are located in the submucosa of the duodenum?
Brunner’s glands
What is the function of Brunner’s glands?
Secretion of an alkaline fluid to neutralize acidic chyme.
How many submucosal glands do we find in the jejunum?
The jejunum has no submucosal glands.
What glands can be found in the submucosa of the stomach?
There are no submucosal glands in the stomach. The gastric glands are located in the gastric mucosa.
What do we call the lymphatic structure that assists with the absorption of fat in the intestinal villi?
Lacteal
Where are paneth cells unique to?
The small intestine.
(Specifically the base of the intestinal glands in the small intestine)
Where are Brunner’s glands located histologically?
In the submucosa of the duodenum
What cells of the small intestine secrete lysozyme, alpha-defensins, and other glycoproteins for antimicrobial defense?
Paneth cells
What prevents the plicae circulares from ever laying completely flat?
The plicae circulares have a submucosal core
Histologically speaking, where are intestinal glands found?
Throughout the mucosal layer of the entire small intestine
If you’re looking at a section of small intestine, and you see no Peyer’s patches and no Brunner’s glands, what section of the small intestine are you looking at?
The Jejunum
Which part of the intestine typically has the longest villi?
The jejunum
What do we call the simple columnar cells of the large intestine?
Colonocytes
What is the primary indicator histologically of a slide coming from the colon?
A multitude of goblet cells without villi
What layer, in the colon, forms the tinea coli?
The outer longitudinal layer of the muscularis externae
What protein is defective in Hirschprung’s disease?
The RET gene, which is responsible for neural crest cell development
What is the basic pathophysiology of Hirschsprung’s disease?
Neural crest cells fail to differentiate causing an absence of the plexus of Auerbach in the colon. This results in absent peristalsis, and leads to megacolon through impactions.
What is the most common type of Hirschsprung’s disease?
“Short segment disease” – where the issue is confined to the “rectosigmoid region” (rectum and sigmoid colon).
What two diseases are included in the term Inflammatory Bowel Disease?
Ulcerative colitis and Crohn’s disease
What histological region is affected by ulcerative colitis?
Specifically the mucosa of the large intestine.
Where is damage from Crohn’s disease localized?
The terminal ileum
(However it has been observed in the large intestine as well)
What are the three divisions of the anal canal?
The colorectal zone, the anal transitional zone, and the squamous zone.
Where does the enteric nervous system end?
At the anal transitional zone of the anal canal
Where are anal glands found?
Extending into the submucosa and muscularis externa of the anal canal.
What are the anal columns formed from?
Mucosal folds of the anal canal
What type of glands are the circumanal glands?
Simply apocrine sweat glands in humans
