Lipid Metabolism Flashcards
What are the dietary lipids?
-triacylglycerols (TAGS)
-fat soluble vitamins (FSVs)
-cholesterol and cholesteryl esters (CEs)
-phospholipids (PLs)
TAG digestion in the stomach
using gastric lipase:
breaks down some TAGS into DAGS (diacylglycerol) + fatty acids (FAs)
TAG digestion in the small intestine (short story)
-bile creates emulsification droplets
-pancreatic colipase and lipase
TAG digestion in the small intestine (long story)
-cholecystokinin is secreted by the duodenum
-acts on pancreas to secrete digestive enzymes pancreatic pancreatic lipase & colipase
-acts on gallbladder to secrete bile
-bile breaks up fat gobules into small emulsification droplets
-colipase allows lipase to enter emulsification droplets
-lipase breaksdown TAGS & DAGs into MAGS (monoacylglycerol) and free fatty acids
What are the products of digestion?
MAGS and FAs
Lipid absorption
mixed bile salt micelles transport lipids to brush border for absorption
Emulsification droplets become what once digestion is complete?
mixed bile salt micelles
Absorption of MAGs + FAs occurs via
transporters at the brush border
What do products of digestion go?
the endoplasmic reticulum
What carries MAGs + FAs to the endoplasmic reticulum
transport proteins
What transport protein specifically carries the products of digestion to the ER?
via fatty acid binding protein (FABP)
What happens in the ER?
MAGs + FAs turn into TAGs
What happens in the ER after the reesterification of TAGs
the TAGs are then packaged into chylomicrons and enter the lymph for transport to the heart
What happens during ruminant lipid digestion
-TAGs turn into glycerol + FAs
-biohydrogenation of PUFAs
What is the process of lipid digestive in a ruminant?
-microbes breakdown TAGs into glycerol + FAs and the glycerol is converted to UFAs which are absorbed through the rumen wall
-FAs from plant material are polyunsaturated fattyacids (PUFAs)
-microbes bihydrogenate PUFAs into saturated fatty acids (SFAs)
-SFAs continue on through the digestive tract for absorption in the S.I.