GI III Flashcards
What epithelium comprises the small intestines?
Simple colunmar with goblet cells
What is the function of the intraepithelial lymphocyte?
T cells that function for immune surveillance
What is the term for the lymphatic channel in the small intestine inside willi?
Lacteal
What is the function of the muscular layer surrounding lacteal?
Compress lacteal to move fat
What are the crypts of liberkuhn? What layer are these found in?
Invaginations of the epithelium of the small intestines.
What type of CT is in the lamina propria?
loose CT
True or false: the lamina propria of the small intestines are well endowed with blood and lymphatic vessels?
True
What are panth cells? What do they look like histologically?
Cells in the small intestine glands that secrete defensins, lysozyme, and TNF-alpha
Have granules in the apical domain
What are enteroendorcrine cells? What do they look like histologically?
Cells in the basal domain of intestinal glands that secrete hormones
Granules at the basal domain towards arteries
Which side of the small intestine are paneth cells found in the glands?
Right side
What epithelium comprises the duodenum?
Simple columnar with goblet cells
What glands are the hallmark feature of the duodenum? What is their function?
Brunner’s glands–secrete alkaline mucus and human epidermal growth factor
Where are Brunner’s glands more numerous: proximal or distal duodenum?
Proximal
Which wall is thicker: the jejunum or the ileum?
Jejunum
What is the function of the secretions of Brunner’s glands?
Mucus is basic
Human epidermal growth factor–grows epi
What is histologically remarkable about the jejunum relativeto other segments?
Nothing, really
Are there Plicae circularis in the ileum?
No
What is the epithelium of the Ileum?
Simple columnar with goblet cells
What is the distinguishable features of the ileum?
Peyer’s patches (lymphatic nodules)
What are M cells?
Antigen transporting cells in the ileum
What are Teniae coli?
3 Longitudinal bands of the muscularis externa
Why are the walls of the large intestine weaker, relative to the small intestine?
Only have circular band of muscularis, as the longitudinal one is split into three in the teniae coli
What are haustra?
The bubbly things in the large intestines
What does the large intestine have instead of plicae circulares?
Plicae semilunares
Does the large intestine contain villi?
no
What happens to the tenia coli in the rectum?
Splays out to form another complete layer to the externa
What epithelum comprises the large intestine?
Simple columnar with increasing density of goblet cells
What happens to the number of goblet cells as you progress through the large intestine?
Increase in number
Which has a well developed brush border: small or large intestines?
Small
What is characteristic of the glands of the large intestine compared to the small intestine?
Intestinal glands are more numerous and longer
True or false: the lymphatic vessels are well developed in the large intestine
False
What layer are the lymphatic channels in, in the large intestine?
lamina propria
How do lymphatic channels spread in the large intestines?
Radially
Are there M cells and lymphatic patches in the large intestine?
Yes
Does the appendix have villi?
No
Which layer are the lymphatic nodules in, in the appendix?
Lamina propria and submucosa
Does the appendix have teniae coli?
No–has two complete layers like small intestine
The mucosa of the appendix resembles (blank), whereas the muscularis resembles (blank).
[small/large intestine]
The mucosa of the appendix resembles the large intestine, whereas the muscularis resembles the small intestine.
What makes the appendix and illeum similar? Different?
Similar = lymphatic tissue Different = no villi
What are the two mechanisms that can bring about appendicitis?
Fecaltihs
Infection of wall
Will the muscularis of the rectum have two complete layers to the muscularis externa?
Yes
What are the three permanent folds of the rectum? What layers comprise these?
Transverse rectal folds (valves of Houston)
Comprised of mucosa, submucosa, and muscularis externa
What is the line that divides the anal canal from how it is derived during development?
Pectinate (detate) line
Above the pectinate line, what are the layers derived from? Below?
Above =Hindgut
Below = Proctadeum
What is the innervation above and below the pectinate line?
Above = ANS Below = Somatics
Where does lymph from below the pectinate line drain to? Above?
Above = abdominal lymphatics
Below = Superficial inguinal nodes
What is the epithelium above the pectinate line?
Above = Simple columnar with goblet cells
Below =
What are the anal column?
longitudinal folds of submucosa and mucosa
What are the anal valves and sinuses?
Valves/sinuses located between distal and adjacent anal columns
What/where is the internal hemorrhoidal plexus?
Venous plexus in the submucosa above the pectinate line
What are the anal cushions?
Musoca of CT, smooth muscle, and blood vessels in the anal canal that function in anal continence
Where are the three anal cushions located when looking at the anus in a supine position?
Left lateral
Right anterior
Right posterior
What is the clinical significance of the anal cushions?
Where hemorrhoids develop
What is the epithelial composition below the pecinate line?
Stratifed squamous keritinized
What is the white line of Hilton?
Transition area in the anal canal that separates the internal and external anal sphincter
What is the function of the anal sinuses?
Glands empty into these spaces
What is a fistula in ano?
Abscess formed fistula that connects the external surface of the anus to the rectum
What are the two major reasons that the wall of the sigmoid colon is weak? What is the clinical significance of this?
Blood vessel penetration
Incomplete transverse muscularis externa
Diverticula
What is the difference of false and true diverticula?
True = Involve all layers of the intestinal wall
False = just mucosa and submucosa
How do colonic polyps develop?
Robust proliferative activity of colonic cells
What are the two architectural patterns that colonic polyps can form? Which one is more likely to become invasive?
Tubular
Villous (invasive)
Are the lymphatics of the large intestines better developed in IBD?
yes
What is the stain that you would use to label the lymphatic vessels of the large intestines?
D2-40
What part of the GI tube can Crohn’s disease impact?
Anywhere from mouth to anus
Where is ulcerative colitis located?
Large intestine and perhaps the distal ileum
What may form in Crohn’s disease from fissures of the walls of the GI tube?
Fistula
What is Hirschsprung’s disease? What does it cause, and where is this issue ALWAYS found?
Aganglionic colon d/t incomplete migration of neural crest cells.
Causes megacolon in the rectum
