Get the list of tables used in a stored-procedure for a database
If you use dynamic SQL to construct table names (or accept them as arguments), or use nested views, it becomes very difficult to automate this. However if you stick to traditional T-SQL and proper references you can get there with this:

DECLARE @procid int = OBJECT_ID(N'dbo.procedurename');

;WITH src AS 
(
  SELECT name = 
      COALESCE(QUOTENAME(d.referenced_server_name)   + N'.', N'')
    + COALESCE(QUOTENAME(d.referenced_database_name) + N'.', N'')
    + QUOTENAME(d.referenced_schema_name) + N'.'
    + QUOTENAME(d.referenced_entity_name)
  FROM sys.sql_expression_dependencies AS d
  WHERE d.referencing_id = @procid
)
SELECT name FROM src GROUP BY name;


And if you just want a catalog of all references, you can do this:

;WITH src AS 
(
  SELECT [procedure] = QUOTENAME(s.name) + N'.' + QUOTENAME(o.name),
      ref = 
      COALESCE(QUOTENAME(d.referenced_server_name)   + N'.', N'')
    + COALESCE(QUOTENAME(d.referenced_database_name) + N'.', N'')
    + QUOTENAME(d.referenced_schema_name) + N'.'
    + QUOTENAME(d.referenced_entity_name)
  FROM sys.sql_expression_dependencies AS d
  INNER JOIN sys.objects AS o
  ON d.referencing_id = o.[object_id]
  INNER JOIN sys.schemas AS s
  ON o.[schema_id] = s.[schema_id]
  WHERE o.[type] = N'P'
)
SELECT [procedure],ref 
  FROM src
  GROUP BY [procedure],ref;