For further clarification, the 3 to 5 in brass notes is because the instruments one vibrate at certain frequencies which are related to the length of the route the air takes through the instrument. The valves, and in case of the trombone the slide, increase the length of the pipe and change the frequency it will vibrate at, changing the tone.

Your lips however can make a lot more notes depending on your ability to control your muscles in your lips.