Look closely and you will see a pale yellow fluid around the wound. This liquid is called serum, and it consists of the remains of plasma after the clotting agents have gone to work. Now we're getting to the really important part, because this yellow liquid is of especial interest to us. Because, in addition to all its other transport functions, plasma also provides the medium in which cholesterol circulates inside us. But it is here that the body faces a major problem.
Cholesterol is a fat-like substance.
Blood, on the other hand, is water-based. The body's answer is characteristically ingenious. It does not try to mix fats directly with water, but instead, packages them into tiny little parcels, which can then be washed around in the bloodstream with the rest of the fluids. At this point we need to use a few scientific labels, because there are several different types of packages, all with different functions and different names. In a moment, we'll look at some of these lipoproteins in more detail.