PSAUTHITEM: Page Permissions. This table stores the information about the page level access for a permission list.
PSROLECLASS: Role Classes table. A many to many relationship table between Roles and Permission Lists.
PSROLEDEFN: This table stores information about Peoplesoft Role definitions. Users get permissions to PeopleSoft objects through Roles, which are assigned Permission Lists.
PSROLEUSER: This table stores information about the Users in Peoplesoft and the roles assigned to them.
PSCLASSDEFN: Permissions List definitions table. Permission list name can be found under Field Name CLASSID.
PSOPRDEFN: Users/Operator definition table. This table stores information about PeopleSoft users. This is the core table for User Profile Manager.
PSOPRCLS: Users/Operator and Perm list mapping Table. This table stores information about PeopleSoft users and the permission lists attached to those users.
A User gets these permission lists indirectly through the roles which are attached to the user
Let me know if you have any questions.