lipoproteins

Transports cholesterol away from peripheral cells to liver.

Major factor contributing to atheroma formation

Good lipoprotein

Transports cholesterol to tissues where cholesterol is used to make cell membranes and steroid hormones

More protein and less lipid

Removes 70% of LDL in blood

Oxidized LDL is ingested by macrophages and chemically modified.

LDL enters liver cells by endocytosis and cholesterol is released into liver cells. Helps regulate cholesterol production by liver

Produces insoluble cholesterol and forms foam cells which can cause atheromas

LDL receptors on liver cells bind LDL

LDL receptors on macrophages bind oxidized or chemically modified LDL

Removal of LDL by this pathway when LDL receptor number decreases or when blood LDL levels are abnormally high.

High blood cholesterol levels due to genetic abnormality that results in deficient number of LDL receptors or defective LDL receptors

High blood cholesterol levels due to increase in cholesterol synthesis caused by diet high in saturated fats. This causes an increase in cholesterol content of hepatocytes (liver cells) Hepatocytes ia decrease in LDL receptor activity in the liver