Digestive System Part 2 Flashcards
How much surface area does the small intestine have available for absorption?
200 m^2
What cytoskeletal element is in the core of microvilli?
Actin
Small intestine mucosa is what kind of epithelium?
Simple columnar epithelium
What are enterocytes?
These are the absorptive cells of the small intestine and this term is only used in the small intestine
Small intestine simple columnar epithelium has what apical specialization?
Microvilli or striated border
The submucosa of the duodenum has what glands that produce alkaline mucosa?
Brunner’s glands
What are the intestinal glands also called?
Crypts of Lieberkuhn
Villi in the duodenum have what kind of appearance in cross section?
Leaf like, they are wide in respect to the other parts of the intestine
What do paneth cells secrete and what does that do?
Lysozymes, this has a defense function against bacteria
What layer of the small intestine specifically does not enter the villi?
The muscularis mucosae
What and where are Peyer’s patches?
Aggregated lymphatic follicles in the ilium, which are groups of lymphatic nodules that are present in lamina propria and submucosa
What specific cells overly Peyer’s patches?
M (microfold) cells, which are specialized epithelial cells
What are two things that the small intestine have that the large intestine does not have?
Plica circualis, and villi
What is the teniae coli?
Outer muscularis layer of the large intestine that runs in a line
What are haustra?
Out pouchings on the large intestine created by teniae coli
What is the epithelium of the large intestine?
Simple columnar epithelium, with crypts of Lieberkuhn (there are lots of goblet cells)
Are paneth cells present in the large intestine?
No, these would be counter productive as they would kill bacteria and in the large intestine we have natural flora that must be there.
Describe the muscularis externa.
There are two layers and the outer layer is longitudinal
What is referred to as the tonsil of the abdomen?
The appendix
What are the three zones of the anal canal?
1) Colorectal zone
2) Anal transitional zone
3) Squamous zone
Describe the colorectal zone of the anal canal.
This is the superior 1/3, and is simple columnar epithelium
Describe the anal transitional zone of the anal canal.
This is the middle 1/3, mix of simple columnar epithelium, stratified columnar (or cuboidal) epithelium, and stratified squamous epithelium
Describe the squamous zone of the anal canal.
Distal 1/3, non-keratinized stratified squamous epithelium, at the distal end is another mucocutaneous junction
What typical small intestine layer ends in the anal transition zone of the anal canal?
The muscularis mucosae
