Jane was sitting in anatomy class on day when her teacher asked her a question. He inquired, What grows to 10 times its original size when excited?
Jane blushed and said that she didn't know. Jimmy raised his hand and said, I know! The pupil of the eye. The teacher replied, Yes, very good Jimmy.
The the teacher turned to Jane and said, Jane I have three things to say to you: One -- you have a very dirty mind. Two -- you haven't been studying hard enough. And three -- you're going to be very disappointed!