Digestion & Absorption 2 Flashcards
Two types of lipids?
Saturated & unsaturated
Where in the body are lipases produced
- Pancreas 2. Stomach 3. Mouth
What is the role of Bile salts?
Emulsifiers. Large fat droplets made smaller
What are the two effects of failure to secrete bile?
- Lipid malabsorption- steatorrhoea 2. 2ndary vitamin deficiency cos of failure to absorb lipid vitamins
Why can’t lipase work on lipids in the presence of bile
bile blocks access of enzyme to the lipid
Role of co-lipase?
Binds to bile and lipase, allows access of lipase to tri, diglycerides
What is the main enzyme used in digestion?
Pancreatic lipase Triglyericeride–> free fatty acids
What are the products of pancreatic lipase breakdown of lipids?
- 2- Monoglyceride 2. Fatty acids (2X)
What is the principal form of transport in lipid absorption?
Passive diffusion. From micelles to the apical membrane
Where are the products of digestion stored and later released from?
Mixed Micelles. Micelles take up lipids and solubilises them, allowing their transport into the enterocytes of the GI tract.
Short chain fatty acids can transport through enterocytes into the capillaries, Long chain fatty acids cannot. What happens to these?
Incorporated into chylomicrons
Chylomicrons are carried in lymph vessels into the systemic circulation by what cells?
Lacteals
Chylomicrons are metabolised into _ and _ by which enzyme?
Free fatty acids & glycerol
Lipoprotein lipase
How is cholesterol absorbed?
Endocytosis by Neimann-Pick-C1 Like 1 protein (NPC1L1). NPC1L1- drug target in Ezetimibe
How is Ca absorption regulated?
Absorption can be passive or active Regulated by - 1,25-dihydroxyvitamin D3 - Parathyroid hormone (produces the above)
