What are the 3 regions of the small intestines, and their respective lengths?
1. Duodenum = 10 in.
2. Jejunum = 8 feet
3. Ileum = 11.5 feet
Villi and Plicae circularis in the small intestine do what?
How much surface area is with the small intestine?
1. Increase surface area
2. 1/2 acre
What are plicae circularis?
What are villi?
1. folds in the small intestine looking like hair scrunchie
2. finger-like extentions on the plicae circularis folds
What type of cells make up the surface of the villi?
What is located inside the villi on a histology slide (spotted region deep to simple columnar epi cells)?
1. Simple columnar epithelial cells imbedded with goblet cells
2. lamina propria with capillaries, venules and lacteals
What is are located on the tips of the villi?
Brush border enzymes
What are lacteals?
What are their functions?
1. Lymphatic vessels in the small intestines
2. Absorb fat molecules
What are fthe glandular structures found at the very base of villi?
Crypts of lieberkuhn
___________ _______________ are found throughout the GI tract, but are more commonly seen in the Ileum and Colon.
What shape is the duodenum?
What important process finishes here?
The duodenum receives what 2 important secretions to do so?
2. Carbohydrate, Lipids & Protein digestion
3a. Bile Secretions via bile duct
3b. Pancreatic Secretions via pancreatic duct
Duodenum glands are called what?
What do they secrete?
1. Brunners Glands
1. When do Brunners glands kick in?
2. What will finish off any protein digestion once Pepsin is inert?
1. When acidic chyme shows up to bring pH up to 7, stopping digestion of protein (pepsin)
2. Pancreatic secretions
The mucosa in the duodenum includes what features? (4)
The submucosa includes what?
The muscularis externa includes what (as usual)?
1. Villi, Simple Columnar Epi, Goblet Cells, Lamina Propria
2. Brunners Glands - very specific to Duodenum
3. Circular muscle & Longitudinal muscle
The majority of absorption occurs where?
What are 2 features of the Jejunum?
2. More villi and slightly larger diameter
The Jejunum histology differs from the Duodenum in that it what?
Lacks Bruuners Glands in the Submucosa
1. Most lymphatic tissue is located in which part of the small intestine?
2. Recall from our lymph module what 2 main components are apart of the lymphatic tissue.
2. GALT (Gut associated lymphatic tissue) & Peyer's Patch (not necessarily exclusive to Ileum, but primarily seen here in the submucosa)
Which important vitamin is absorbed here?
1. B12 via intrinsic factor from the stomach
How does food leave the Ileum?
1. via ileocecal vavle
Peyers patch will look like what on histology slide?
What region are they located in the Ileum?
1. large round lymphoid nodules in a group or patch
Villi in Ileum mat be identified by what?
They are short and stumpy