Cholesterol

From ArticleWorld

Cholesterol is a compound found in the cell membranes and transported in the blood of animals. It is made up of a sterol and a lipid. It was initially identified as a solid in gallstones. Cholesterol is synthesized by organisms but can also be obtained from dietary sources. It is of importance to many biochemical processes but is well-known for its connection to heart disease and high cholesterol levels in blood. Cholesterol is referred to according to two terms, bad cholesterol or low-density lipoprotein (LDL) and good cholesterol or high-density lipoprotein (HDL).

Physiology

One major function is as a component of cell membranes as it gives the membrane's fluidity stability in large temperature intervals. It also is important to the manufacture of bile, metabolism of vitamins, and synthesis of hormones and has been proven to be important for brain synapses and the immune system.

Cholesterol due to its insoluble nature in water must be transported by lipoproteins that encases cholesterol internally and moves it through the bloodstream. Lipoproteins can carry triglyceride fats as well as the cholesterol secreted by the liver and derived from food.

The liver converts the cholesterol into LDL particles which in healthy individuals are large and few in number however if the converse occurs and the particles are small and large in number then this can lead to atheromatous disease in the arteries. The HDL particles move cholesterol into the liver for excretion and thus large amounts of HDL particles is often considered better for health. Cholesterol levels are regulated by homeostatic mechanisms which rely on the levels of cholesterol present.

Associated diseases

Cholesterol can result in the formation of atheroma in the walls of arteries especially when small LDL particles are present. This has been linked to diseases such as coronary heart disease and other cardiovascular diseases. Low levels of cholesterol result in a condition termed hypocholesterolemia. This condition is not well researched; however, studies have associated depression, cancer and cerebral hemorrhages to it. More research is necessary to confirm these links.