Other than inserting a hyperlink or cross-reference to a bookmark, or a Table of Contents, any of which can only be used to take you to another location in the document (not expand/condense content), Word doesn't offer that kind of thing. With the aid of formfields/content controls and macros, you could implement something like it, but it'd be clunky at best. Word is, after all, a word processor, not an interactive application designer.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]