Second order Logic (SL) is required to define the Reals (otherwise they were at most countable). Based on this, SL is involved in the definition of the limit operator, as the 'core' of all Calculus.
Now, was that it with SL? Do we need Second Order Logic in Calculus beyond the definition of the limit operator?
If not, this would be a pretty neat example of encapsulation. Very similar to encapsulation in e.g. software architecture (as far as one is interested in an interdisciplinary perspective).