Summary

The original one was in pieces impossible to print.
First because the Brown part was disconected, second cause the details of the Blue and red parts didnt print well in a real size model with a 0.4mm nozzle.
That being said, i connected all pieces and scaled it up to a real size kidney.

If you want, i also split the Brown pieces, tho i dont recommend printing each color appart cause they dont seem to be able to Connect.