Here's a breakdown:

* Disk: This is the main part of the galaxy, containing most of its stars, gas, and dust. It is relatively thin compared to its diameter and rotates like a record.

* Bulge: This is a dense, spherical or ellipsoidal region at the center of the disk. It is usually composed of older, redder stars and contains a supermassive black hole.

* Spiral Arms: These are prominent features that extend outward from the bulge. They are regions of active star formation, containing young, hot, blue stars, gas, and dust.

Think of it like a giant, flat spinning wheel with a central hub.