So, in a system controlled by negative feedback, the set level is never perfectly maintained, but
constantly oscillates about the set point. An efficient homeostatic system minimises the size of
the oscillations. Some variation must be permitted, however, or both corrective mechanisms would
try to operate at once! This is particularly true in hormone-controlled homeostatic mechanisms
(and most are), where there is a significant time-lag before the corrective mechanism can be
activated. This is because it takes time for protein synthesis to commence, the hormone to diffuse
into the blood-steam, and for it to circulate around the body and take effect.