<?php 

  $db = mdb_open("test.mdb");

  print_r(mdb_tables($db, true /* include system tables */))

  mdb_close($db);
?>

Array
(
    [0] => MSysObjects
    [1] => MSysACEs
    [2] => MSysQueries
    [3] => MSysRelationships
    [4] => MSysModules2
    [5] => MSysModules
    [6] => Cities
    [7] => Provinces
)