Lipids are a heterogeneous group of water-insoluble (hydrophobic) organic molecules. Because of their insolubility in aqueous solutions body lipids are generally found compartmentalized, as in the case of membrane-associated lipids, or transported in plasma in association with protein.
Lipids are a major source of energy for the body, and they also provide the hydrophobic barrier that permits partitioning of the aqueous contents of cells and subcellular structures. Lipids serve additional functions in the body, as some fat-soluble vitamins have regulatory or coenzyme functions and steroid hormones play major roles in the control of the body’s homeostasis.
Not surprisingly, deficiencies or imbalances of lipid metabolism can lead to some of the major clinical problems encountered by physicians, such as atherosclerosis and obesity.
1- Total Lipids
Determination of total amount if lipid in blood
Cholesterol, the characteristic steroid alcohol of animal tissues, performs a number of essential functions in the body. For example, cholesterol is a structural component of all cell membranes, modulating their fluidity, and, in specialized tissues, cholesterol is a precursor of bile acids, steroid hormones, and vitamin D.
In humans, the balance between cholesterol influx and efflux is not precise, resulting in a gradual deposition of cholesterol in the tissues, particularly in the endothelial linings of blood vessels. This is a potentially life-threatening occurrence when the lipid deposition leads to plaque formation, causing the narrowing of blood vessels (atherosclerosis) and increased risk of cardio-, cerebro- and peripheral vascular disease.
Fatty acids are transported and stored in the body as Mono-, di-, and triacylglycerols consist of one, two, or three molecules of fatty acid esterified to a molecule of glycerol. Triglycerides act as energy storage in the body and their increase correlated to increase risk of heart diseases and also metabolic diseases.