Tables

select owner, table_name, num_rows
  from dba_tables
 where table_name like '%MY_TABLES_%'
order by table_name

Columns

select owner, table_name, column_name, data_type, data_length, nullable, column_id, data_default,
       -- contents
       num_distinct, low_value, high_value
  from dba_tab_columns
 where table_name like '%MY_TABLES_%'
order by table_name, column_id