Wisdom Tooth & Funny Bone

Someone I know is having their "wisdom tooth" removed.  This may be a silly question, but why is it called a "wisdom" tooth?  Does having it pulled mean you lose your "horse sense"?  IQ drops down to "dumb"?

Since we're on the subject of anatomy, why is the "funny bone" called such?  Hitting your "funny bone" is not really a time of great delight and joy. 

Here's another one..."instep".  As opposed to "outstep"?    Any others?