The DISK of our Galaxy
The disk is extremely flat. Most stars and ALL the gas and dust is found here. 15% of our Galaxy's mass is in the gas and dust (collectively called, the interstellar medium).
The very central portion of the light is blocked out due to dust. Looking just up or down from the thin disk, we start to see star light. The stellar distribution is slightly fatter than the gas and dust.
This is a real photograph of the galaxy, NGC 891. It is seen almost EXACTLY edge on. It looks suspiciously like the images of our disk in the previous page.