After doing the installation of SharePoint 2010, a separate site collection is created for performing different administrative functions that might needed on a daily basis. This site collection is known as Central Administration site. This site collection is different than the site collections which you have created and is run on its own web application in IIS.It is the main point for all the administration related activities for all the SharePoint sites. All farm server administrators is having an permission to access to this site much like the regular site they can edit and customize Central Administration site.