This kind of thinking, that everything can be broken down into pieces and studied in isolation... it has brought us very far, but it has some hard limitations. Especially in biology, where any leak you find may serve some function.

In medicine, the primary goal is to help, rather than understanding why something works exactly. Sure, understanding is an important goal too, it's just much harder to achieve than being able to help. And less important than knowing that your treatment will work, without any major side-effects, for the kind of patient in front of you.