How can research results derived from animal testing be extrapolated to humans?

There are striking similarities between the physiological systems of humans and various species of animals. For example, much of what we know about the immune system has come from studies with mice, and much of what we know about the cardiovascular system has come from studies with dogs.

Research results from animals also provide the information necessary to design human trials that must be completed for legal approval of new devices, drugs or procedures. It is important to be able to gauge how a new drug or procedure will affect a whole biological system before using it on humans. This is critical for scientific as well as ethical reasons. Laboratory animals are an integral part of the research process. In fact, virtually every major medical advance of the last century is due, in part, to research with animals.