While many APs support bridge functionality, an IEEE 802.11 Access Point is *not* inherently a bridge in the IEEE 802.1 sense.
This can be seen when looking at how an IEEE 802.11 AP forwards traffic between the WM and the DS. This is done using the "From DS" and "To DS" bits and 802.11 state machine, without requiring classic bridging concepts such as learning tables. Note that in the IEEE 802.11 state machine, data packets with "From DS" and "To DS" both false can be accepted in State 1 (unauthenticated, unassociated). If IEEE 802.11 APs were bridges, presumably they would "learn" MAC addresses from these packets. Of course, they don't do this, but instead there is an explicit Association/Reassociation exchange. In IEEE 802.11F the completion of this exchange causes the AP to send an 802.2 XID frame with SA equal to the STA MAC address, in order to initiate learning in attached switches. Today many APs do something similar -- so that learning is initiated prior to receipt of the STAs first packet sent in State 3. -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless
