Where does the "purring" sound come from inside our cats?

From an anatomical standpoint, can someone answer where a cat's "purring" sound comes from in a cat?  Also, how do cat's make that noise, does it come from the throat area?   Just curious.  Thanks

Cats have special wiring! The wiring travels from the brain to the muscles in the voice box, and this wiring is able to vibrate the muscles so that they act as a valve for air flowing past the voice box. The muscles work both during inhalation and exhalation, which creates the impression that cats can purr continuously. The air passes through the valve, which opens and closes rapidly to create the purring sound. Source.

Thank you for a reply.  You painted a good mental understanding of how their purring is done.  We know that purring by a cat is turned on and off at the will of the animal, where as say "night vision", as mentioned in that  article you had attached is an "added feature" lets say by God to allow the animal to see in the dark.  Now, where as "purring" as totally at the whim of the cat. I know, some things  in life we are expected to just "accept" and not question.  Maybe one of these days Katy will   TELL ME  how she turns that God given feature she has on and off.    I know it has to do with emotions.   Thanks moorspede.

Yes, one of those being comfort. The low vibrating sound is supposed to comfort a cat when it is unwell or scared. 

I didn't know this, very interesting, thanks for asking & sharing.

I've just always been one who likes to understand how things work and the "why they work".  I'm glad I asked the question too, Greypaws.