[ubuntu] Difference between the host and the guest OS kernel versions

I had installed Ubuntu 12.04 64-bit on my Laptop (host OS) when it was released (around April, 2012) and after applying all the patches (sudo apt-get update;sudo apt-get dist-upgrade), the version of Linux kernel is
uname -r
3.2.0-53-generic
Recently I downloaded ubuntu-12.04.3-desktop-amd64.iso and used if for installing a guest OS on top of VirtualBox, the default Linux kernel is
uname -r
3.8.0-29-generic
And 3.8.0-34 is available on doing a dist-upgrade on the guest.


Why is not the kernel version getting upgraded to 3.8.0-* on the host OS even after a dist-upgrade? I am getting the rest of the upgrades though.

Also, because of the kernel mismatch I am not able to install the VirtualBox guest additions.