Dietary Fats and Blood Lipids Flashcards
what are lipids?
group of organic substances soluble in organic solvent and virtually insoluble in water
what are the 3 main classes of lipids?
cholesterol
triglycerides
phospholipids
why is it important cholesterol allows the synthesis of bile acids?
allows absorption of fat soluble vitamins (A,D,E,K)
what is the role of cholesterol?
-component of all cell membranes
-synthesis of bile acids
-precursor for endogenous Vit D production
-precursor for steroid hormones
which steroid hormones is cholesterol a precursor for?
-oestrogen and progesterone
-testosterone
-cortisol
-aldosterone
what is the use of triglycerides?
used as an energy source in tissues
used for energy storage in adipose tissue
essential role but too much can increase risk of heart disease
what is a lipoprotein?
-complex spherical structure
-central core of hydrophobic lipids (triglycerides and cholesterol esters)
-surface layer of polar components (phospholipids, free cholesterol, proteins- the apolipoproteins)
what is the lipoprotein system?
evolved to solve the problem of transporting fats in the aqueous environment of plasma
what are the types of lipoprotein found in the body? (least dense to most dense)
-chylomicron
-VLDL
-LDL
-HDL
what is the function of chylomicron?
synthesised in then gut after a meal
main carrier of dietary triglyceride
what Is the function of VLDL?
synthesised in the liver
main carrier of endogenously produced triglyceride
what is the function of LDL?
generated from VLDL in the circulation
main carrier of cholesterol
what is the function of HDL?
returns cholesterol from ectrahepatic tissues to the liver for excretion
what are apolipoproteins?
-amphiphilic compounds
-hydrophobic region interacting with lipid core
-provides structure to the lipoprotein
-hydrophilic region interacting with aqueous environment
what is the role of apolipoproteins?
play a crucial role in lipid metabolism
-guiding the formation of lipoproteins
-acting as ligand for lipoprotein receptors
-sering as activators or inhibitors of enzymes involved in the metabolism of lipoproteins
which apoprotein binds with LDL receptors to allow cholesterol to get inside the cells?
APOB100
what happens during the exogenous cycle?
-food is ingested and dietary lipid is absorbed
-goes into the circulation as chylomicron (big and fluffy)
-acted on by lipoprotein lipase to form chylomicron remnants which are then taken up by the liver
what connects the exogenous and endogenous cycles?
liver
what is cardiovascular disease?
circulation - ischaemic heart disease (angina, myocardial infarction
cerebral circulation - stroke
peripheral circulation - peripheral vascular disease
premature CVD - males onset CVD<55, females onset CVD<65
what happens during the endogenous cycle?
liver produces very LDL particles
-relessed into circulation
-broke into IDL
-broke down further into LDL
-can either circulate back and be taken up by LDL receptors in liver or extra hepatic cells