L 23 - Digestion and Absorption Flashcards
What are the two types of villus cells?
- Goblet cells = mucus secreting 2. Columnar absorptive cells
What are the three Crypt cell types?
- Columnar cells 2. Paneth cells 3. Stem cells
What is the histological difference when comparing Jejunum and Ileum to the Duodenum?
J and I: longer villi and no brunner’s glands
What layer are the crypts of Lieberkuhn located?
in the lamina propria of the mucosa - open between base of villi
Which cells are only found in ruminants and horses?
Paneth cells = produce immune mediators and peptidases
What are the 3 specialisations for absorption in the small intestine?
- Plicae 2. villi 3. microvilli
What fold at the apical of the cell membrane and are known as the “brush border”?
Microvilli
What are plicae?
mucosal/submucosal folds
What are enterocytes and where are they found?
Simple columnar epi cells found in the small intestines - absorptive cells -ovoid basal nucleus
What is the brush border on microvilli made out of ?
Glycocalyx
What type of cells are these?
Paneth cells: only found in horses and ruminants - prominent eosiniphillic granules: = antibacterial role (peptidase and lysozymes)
What type of cells are theses from?
Duodenal Brunner’s glands - found in the submucosa -empty into the base of crypts -secretions: - mucuous = dogs and ruminants - serous = horses and pigs
What cells secret chloride?
Columnar cells
What type of cells are these?
Goblet cells: - produce mucus so it stains poorly interspersed between columnar and villus - less numerous at tips of villi
Which cells produce mucus in the small intestine?
- goblet cells on villi 2. submucosal glands = brunner’s glands in duodenum 3. submucosal glands = mucous in dogs and pigs
Where are digestive enzymes secreted from in the small intestines?
Surface columnar absorptive cells 2. paneth cells (in ruminants and horses)
Describe the histology of the large intestine
- longer, less coiled simple tubular intestinal glands with MANY GOBLET CELLS = lots of mucus 2. NO submucosal glands 3. NO paneth cells
What factors will inhibit Na absorption?
- increase in cAMP (prostaglandins, cholera toxin) 2. increase in cGMP (E coli toxic agent) 3. increase in intracellular calcium (acetyl choline)
What uses primary active transport ?
Amino acids
What uses secondary active transport and facilitated diffusion?
Monosaccharides
What uses Diffusion?
Monoglycerides
