Lipids & Lipoproteins

lipids function

major energy source for body, stability of cell membrane and cellular structures

major lipids of the body

triglycerides, phospholipids, glycolipids, cholesterol

how are lipids transported in the body

in the form of lipoproteins

fatty acids

major constituents of triglycerides and phospholipids

unsaturated, monosaturated, polysaturated

two sources of triglycerides

exogenous (dietary) and endogenous (hepatic)

triglyceride make up

one glycerol molecule and three fatty acids

how are triglycerides transported throughout the body

in the form of chylomicrons and VLDLs

cholesterol function

precursor for five major steroid hormones, manufacturing cell membranes, synthesis of bile acids and vit D

cholesterol

steroid that exists in almost all cells

cholesterol sources

endogenous and exogenous

phospholipid function

cell membrane stabilitiy

glycolipid function

cell membrane stability, cell to cell recognition, blood typing

apolipoproteins

found on the surface of lipoproteins; help maintain structural integrity and direct the different lipids to the correct target organs

four major lipoproteins

chylomicrons, LDL, VLDL, HDL

lipoprotein function

transport lipids throughout body

chylomicrons function

transport dietary triglycerides and cholesterol to rest of body

VLDL function

transport hepatic triglycerides to rest of body

LDL function

carry cholesterol from the liver to tissues

why is LDL a bad cholesterol

associated with lipid deposition in blood vessels and high serum levels are CHD risk factor

HDL function

carry cholesterol from tissues to be reutilized by liver

why is HDL good cholesterol

because it removes cholesterol from the blood and returns it to liver

what does Lp(a) in the blood indicate

independent risk factor for the development of CHD, MI, etc

three lipoprotein pathways

endogenous: hepatic lipids via LDL and VLDL

exogenous: dietary lipids

reverse cholesterol: HDL

lipoprotein receptors function

lipoproteins must complex with receptors (apolipoproteins) in order to be metabolized in the body

total cholesterol range

140-200 mg/dL

HDL range

29-75 mg/dL

LDL range

57-130 mg/dL

triglyceride range

67-157 mg/dL

dyslipidemia

diseases associated with abnormal lipid concentrations

arteriosclerosis

deposition of lipids in arteries, leads to plaque build up that occludes blood vessels

combined hyperlipidemia

increased levels of cholesterol and triglycerides

hypoalphalipoproteinemia

associated with HDL

hypobetalipoproteinemia

associated with LDL

lipid panel

measures total cholesterol, HDL, triglycerides, and LDL

LDL often not directly measured

organization that developed performance goals for lipid testing

National Cholesterol Education Program (NCEP)