Blood and blood products are collected as whole blood from donors in various anticoagulants. The blood and blood products which are used for transfusion are whole blood, packed red blood cells (PRBCs), platelet concentrates, fresh frozen plasma (FFP), cryoprecipitate, and plasma derivatives. Plasma derivatives are also used for transfusion such as albumin, intravenous immunoglobulin, anti-thrombin, and coagulation factor concentrates. Plasma derivatives are generally collected from several donors and pooled together and infectious organisms are removed by treating.

Separation of blood components from whole blood:

Blood is collected as whole blood of 450 ml (one unit of blood) in various anticoagulants. The whole blood is then processed to produce blood various blood components mentioned above. Most commonly blood is transfused as whole blood. To get blood components, whole blood is first separated by slow centrifugation into PRBCs and platelet rich/concentrated plasma.

Obesity is caused by complex interaction of genetic and environmental factors. It is difficult to determine if genetics play a dominant role or environmental factors play the dominant role in causation of obesity. In general a favorable environment and a genetic susceptibility interact to cause obesity.

The actual causes of obesity are still not clear despite tremendous development in medical science, including understanding of molecular pathways which regulate energy balance in humans, an essential component in pathogenesis of obesity. The cause obesity seems to be simple, such as chronic and excess consumption of food (calories) than expenditure of energy. But this theory of chronic excess nutrient intake relative to the level of energy expenditure does not hold in every obese individual, which proves that there are several other causes of obesity than simple consumption of excess food than we need.

Genes vs. Environment in Obesity: