Instruction Register + 1 = GOTO next memory location
If A then B = Branch if equal = GOTO ADDR B
call function = put currebt address in stack and GOTO this address, then GOTO address on stack.
It seems to me that it is just GOTO all the way down. In fact there really is nothing else but Memory and GOTO.
Sort of ironic that the very foundations of machine computing is not a very good idea....