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Cholesterol

“Statins for all! …. but isn’t cholesterol a vital cellular component? ” Nowadays, many people associate cholesterol with diseases and refer it to something harmful to human body; however, cholesterol is not all bad. In fact, it is one of the essential cellular components in animal cells. Figure 1 (NIGMS, 2011) Figure 2. (Medex UK, 2009) Cholesterol is a waxy steroid, mostly made by in the liver and found certain foods, such as food from animals, like dairy products, eggs and meat.

Cholesterol is needed in the body for various functions such as insulating nerve fibres, making hormones such as sex hormones and steroid hormones and for making bile acids, which are essential for the digestion and absorption of fats, while the most vital function of that is to make up the membrane structure of every cell in the body (Stanfield, 2010). The living cell is being separated from its surroundings by plasma membrane, consisting of phospholipid bilayer which has a fluid structure (Stanfield, 2010).

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It is very important that the plasma membrane to retain its fluidity under specific environmental conditions. If the membrane solidifies or if it is too fluid, the function of some proteins in it may become inhibited. This is where the role of cholesterol becomes increasingly significant. At different temperatures, cholesterol has different effects on membrane fluidity. It acts as “fluidity buffer” for the membrane, inhibiting the changes in it which could be caused by changes in temperature (Reece et al. 2011, p. 174). Cholesterol restricts the membrane fluidity through restraining phospholipid movement at relatively high temperature; however, it lowers the temperature at which membrane solidify by avoiding phospholipids to pack closely (Reece et al. , 2011). Furthermore, cholesterol is important in formation of areas, called “lipid rafts” (see Figure 1), which act as platforms for the assembly of signalling proteins within the membrane.

These are the regions of high cholesterol and corresponding low fluidity caused by tight packing of cholesterol molecules against phospholipid molecules, and can float freely in the membrane bilayer (Harvard University, 2010). On the other hand, cholesterol can cause serious health conditions in the body, if raised over an extent point in the blood. There are mainly two types of cholesterol transporter, LDL (Low Density Lipoprotein) which is known as bad cholesterol and HDL (High Density Lipoprotein) which is known as good cholesterol.

LDL is the main cholesterol transporter and carries cholesterol from liver to cells. If there is too much of it in the blood, cholesterol may build up in the wall of artery blood vessels, narrowing the arteries (see Figure 2) and cause serious heart diseases such as coronary heart disease (Stanfield, 2010). In order to lower the LDL cholesterol level of the blood, statins are prescribed. Statins reduce the production of cholesterol by the liver by inhibiting 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, an enzyme involved in cholesterol synthesis, especially in the liver (JFC, 2011).

Statins are considered for all patients with symptomatic cardiovascular diseases; however, they can cause various side-effects such as muscular side-effects, gastro-intestinal disturbances, and sometimes pancreatitis (JFC, 2011). On the whole, cholesterol is an essential structural component and without it, body would not function as normal. Nevertheless, if rises over a certain level in the blood, statins considered in order to reduce the risk factor of such diseases. Word count: 538 words. References:

Harvard University. (2010). The inner Life of The Cell. Retrieved October 28, 2011, from http:multimedia. mcb. harvard. edu/. Joint Formulary Committee. (2011). British National Formulary. (61st ed). London: British Medical Association & Royal Pharmaceutical Society of Great Britain. Medex. (2009). High Cholesterol. Retrieved June 11, 2011, from http://www. ighcholesterol. me. uk . National Institute of General Medical Sciences. (2011). Inside The Cell. Retrieved June 11, 2011, from http://publications. nigms. nih. gov/insidethecell/chapter2. html. Reece, J. B. , Urry, L. A. , Cain, M. L. , Wasserman, S. A. , Minorsky, P. V. & Jackson, R. B. (2011). Campbell Biology. (9th ed. ). San Francisco: Pearson Education Inc. Stanfield, C. L. (2010). Principles of Human Physiology. (4th edition). U. S. A: Benjamin Cummings.

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