lipid absorption, exogenous, endogenous

• Micelle - single layer of phospholipids; way to transport group of lipids through polar solvent as outside of micelle is hydrophilic but inside is hydrophobic
• Absorption of fats - micelle passes into intestinal epithelium by simple diffusion
• transport of fats - micelles work their way through the epithelial cells (absorptive cells) of the intestine; rather than getting absorbed by capillaries in intestines (too big), enter the lacteal, which are part of lymphatic system; these are able to accommodate larger size of micelle
• when a micelle enters a lacteal, it is a chylomicron
• chylomicrons are the first lipoprotein to appear in the plasma
• once a micelle enters the intestinal epithelia, a second layer of micelle is added with proteins
• Endogenous triglycerides - lipids that are derived from inside our body
• Exogenous lipids - lipids that are transported
• Exogenous pathway - starts with chylomicrons circulating in blood plasma; external; coming from outside; fats we have ingested, absorbed, not to liver yet
• Endogenous pathway - involves lipids and lipoproteins manufactured in the liver
• lipids are digested in the small intestine
• bile salts emulsify large lipid droplets to smaller ones and lipase digests some triglycerides into free fatty acids and glycerole
• bile forms micelle around fats