iFixit

Lift the guts of the base station out of the casing.

There are two large blocks of aluminum on the upper case that Apple is using as heat sinks. The upper case alone is .9 lbs-- over half the weight!

There are three antennas mounted internally: one on front (white cable), left (grey cable), and right (black cable). They all have standard antenna conectors on them.

This is the top of the logic board. Interesting things: 3V (clock?) battery, two Samsung memory chips, and imprinted Apple part #820-1942-A. The processor is covered by a heat sink.

This is the bottom of the logic board. Not much to see here--something large covered by another heat sink. At the top right is a plastic cover over the LED. Four ethernet ports, one USB port, a power jack, and a reset button. The Apple part number on the airport card is 603-9396-A.