yes they are called opcodes!

This example shows with the help of B::Terse how the sub take is called with 1+2 as parameter.

>  perl -MO=Terse -e 'take(1+2)'
LISTOP (0x976cdf0) leave [1] 
    OP (0x9777078) enter 
    COP (0x97542e8) nextstate 
    UNOP (0x975fbb0) entersub [3] 
        UNOP (0x975c8b8) null [142] 
            OP (0x9754818) pushmark 
            SVOP (0x975ca50) const [4] IV (0x9758ea8) 3 
            UNOP (0x975c878) null [17] 
                PADOP (0x975c938) gv  GV (0x9758eb8) *take 
-e syntax OK
[download]

And with B::Deparse you can even back-engineer an equivalent Perl code:

 perl -MO=Deparse -e 'take(1+2)'
take(3);
[download]

> I always thought of Perl as a purely interpreted language.

No that is (was) TCL's problem.

> Also, does anyone have any flow-diagrams of how source code makes it to machine code for each category (compiled, JIT, & interpreted)?

Well this is a Perl board! Look at BEGIN, UNITCHECK, CHECK, INIT and END for compilation phases of Perl.