difference between wxMenu and wxMenuItem ?

[Xu, Ming (NIH/NLM/NCBI) [F]]

wxMenuItem

Hi,
what's the difference between wxMenu and wxMenuItem ?
I would like to dynamically add or remove wxMenu w/ submenus,
But wxMenu::Remove owkrs on wxMenuItem ?
wxMenu::Remove
wxMenuItem * Remove(int id)
wxMenuItem * Remove(wxMenuItem *item)

thanks

ming