Digestion and Absorption
- Created by: lavithedemon
- Created on: 13-04-16 08:17
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- Digestion and absorption
- The contraction of circular and longitudinal muscle layers of the small intenstine mixes the food with enzymes and moves it along the gut
- peristalsis - waves of muscle contraction
- the pancreas secretes enzymes into the lumen of the small intenstine
- glucose and glucagon
- digestive enzymes
- pancreatic juice
- amylase to digest starch
- lipases to digest triglycerides, phospholipids
- proteases to digest proteins and peptides
- pancreatic juice
- enzymes digest most macromolecules in food into monomers in the small intestine
- starch is digested into maltose by amylase
- triglycerides are digested to fatty acids and glycerol by lipase
- phospholipids are digested to fatty acids, glycerol and phosphate by phospholipase
- proteins and polypeptides are digested to shorter peptides by protease
- DNA and RNA into nucleotides by Nucleases
- Maltose into glucose by maltase
- lactose into glucose and galactose by lactase
- sucrose into fructose and glucose by sucrase
- exopeptides digest polypeptides by removing single amino acids to get to a dipeptide
- Villi increase the surface area of epithelium over which absorption is carried out
- Villi absorb monomers formed by digestion as well as mineral ions and vitamins
- glucose, fructose, galactose and other monosaccharides
- all of the amino acids
- fatty acids, monoglycerides and glycerol
- mineral ions
- vitamins such as ascorbic acid
- Different methods of membrane transport are required to absorb different nutrients
- Tryglicerides
- digested in monoglycerides and fatty acids
- simple diffusion in the epithelium
- tryglicerides in order not to flux back
- fatty acids absorbed by facilitated diffusion
- tryglicerides and cholesterol to go into the lacteal - lymph or blood capillaries
- tryglicerides in order not to flux back
- fatty acids absorbed by facilitated diffusion
- simple diffusion in the epithelium
- digested in monoglycerides and fatty acids
- glucose goes into the epithelium with sodium - potassium pumps by active trnasport
- sodium co transporter ions go down their concentration gradient - facilitated diffusion
- Tryglicerides
- The contraction of circular and longitudinal muscle layers of the small intenstine mixes the food with enzymes and moves it along the gut
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