Why were tables imported

[Lazy Days]

I was looking at some sample databases yesterday and since they were in a zip folder, I just told it to open in access instead of downloading and saving them. After doing this, there were some tables showing (in every database on my computer) that were not there before. They are all grayed out even though I can open them and see the contents.
They are:
MSysAccessObjects
MSysACEs
MSysObjects
MSysQueries
MSysRelationships

The database seems to run as intended, but I was curious about these tables showing. The database won't let me do anything with them (this might be a good thing).
Anyone have any ideas on this or seen this happen before?

 

[Lazy Days]

Never mind, I found an answer for my own question. In case anyone else was wondering, here is what I found:

These are system tables that Access creates to hold info about the database. They were ALWAYS there and are there for any new database. The reason you never saw them before is because you were hiding System Objects. For some reason the System Objects checkbox was checked off. To change it back, go to Tools>Options. Under the View tab, in the Show section just uncheck System Objects. This should be unchecked as a matter of course. The only time they should be shown is if you need to view some of the settings and that is very rare.