Starting the Linux Kernel (Boot Process)

I'm trying to understand the Linux boot process: I understand that in the (set by GRUB) first stage, the kernel (as a compressed image file) is loaded into memory and decompressed. When control is passed to the kernel how is this actually done? Is the kernel compiled from its C source code and how is the kernel actually executed. I have read this post, but it does not seem to answer my query: https://unix.stackexchange.com/questions/5184/what-happens-after-loading-the-linux-kernel-image-into-ram