But to expand a little, orgmode has two modes of LaTeX-integration. The first one gets normally passed from text, so you can just use e.g. \emph{} in your orgmode source file. The other is a dedicated LaTeX-environemt (#+BEGIN_LaTeX ... #+END_LaTeX) that puts the appropriate literal LaTeX in the appropriate place within the document. I use its beamer-mode and do any tikz-graphics as literal LaTeX code within the org-file.

Though I do my normal writing simply in LaTeX, because that just deals more neatly with edge-cases, really.