Student was offended at this question in class, but the teacher's retort is just the best

The 10th grade teacher asks Jessica, "What part of the human body increases to ten times its normal size when excited?"

"That's disgusting!" Jessica responds. "I don't have to answer that question!"

So the teacher asks Jamie, who responds: "That's easy... the pupil of the eye."

"That's correct, Jamie. Very good!" The teacher says.

Then turning to Jessica, she announces: "I have three things to say to you, young lady... First, you didn't do your homework; second, you have a dirty mind; and third, you're in for a big disappointment!"