My understanding is that it's just a crescent-shaped slit that the needle cuts and then pushes its way into.  It may take a bit out at larger sizes and when going through tough tissues like cartilage; I don't know.  But I don't think its supposed/expected to.

But...my understandings are frequently incorrect...can anyone confirm?

 a properly beveled needle won't remove tissue.

Then I guess the needles my studio uses aren't that great.. When I got my snakebites (RIP), my piercer was all excited to show me the inside of the needles, which had white stuff in them. Obviously tissue from me!