As Ms. Frizzle leads the way, the class takes a journey through Arnold's digestive system, a pulsating excursion through Ralphie's bloodstream, and an exciting exploration through the Ralphie Robot to learn about bones, joints and muscles.

Based on the characters created by Joanna Cole and Bruce Degan. Exciting extras: A peek inside: a map of the human body lets you select and explore.

For lunch -- Inside Ralphie -- Flexes its muscles.