Middot, Chapter One, Mishnah Four
Todays mishnah lists the seven gates in the Temple courtyard.
1) There were seven gates in the courtyard: three in the north and three in the south and one in the east.
2) In the south: the Gate of Kindling, and next to it the Gate of the First-borns, and then the Water Gate.
3) In the east: the Gate of Nicanor. It had two chambers, one on its right and one on its left. One was the chamber of Pinchas the dresser and one the other the chamber of the griddle cake makers.
Section two: The Gate of Kindling was used to bring in the wood for the altar.
Through the Gate of the First-borns they would bring in first-born animals on their way to being slaughtered. The Water Gate was used to bring in the water used on Sukkot for the water libation (its the most famous gate in history, but for other reasons).
Section three: Mishnah Yoma 3:10, mentions Nicanor and the doors for his gate, which according to legend were brought miraculously from Egypt. This gate was on the eastern side of the courtyard. Within the gate itself there were two chambers. In one sat Pinchas who made the priestly clothing (see Shekalim 5:1) and in the other sat the priests who made the griddle cakes that the high priest would offer every day (see Tamid 1:3).