Is there an adjective that means something is going out of the body at one end and going back in at the other end? I know I used the same picture not long ago, but now I am looking for an adjective to describe the shape. The best phrase I came up with is "hollow convex shape", but that doesn't really says much, because the thing at the end has a "cord-like structure" and one end goes out of the body and the other goes back in right beside it. Is there an adjective for this?
The exact answer to your written question (I cannot open the image) is,
closed-loop Dictionary.com adjective; of or relating to a processing system in which effluents are recycled, that is, treated and returned for reuse.
dialysis could be associated with this, but you can have dialysis without it being directly returned into the body.
However, I am unsure that what you asked was what you meant to ask?