I don't believe Joomla inherently supports multiple access levels (other than "super administrator", "administrator", "manager") but there are extensions out there that allow you to do this. Check
this page for them.
I haven't really seen any CMS that incorporates this idea fully (as opposed to people making these as add-ons), and I'm not sure why they don't, but I understand it's definitely a must-have for sites that have more than one user managing content.
Hopefully this helps you out!