wondering about spiders

Do spiders defecate or urinate? If so, how? Does this interfere with the spinnerets at all?
(Where’s that guy who had the pet spider?)

I’m looking at an anatomical chart of a spider. The anus is just above the spinnerets at the spider’s posterior. I don’t see one, so I’m guessing there isn’t a separate external urinary opening. The genital opening, by the way, is separate, and is on the ventral side.