What is dialysis and how does it work?

Its a process that allows people with kidney faliure to get blood filtered 1)unfiltered blood high in urea taken from blood vessel in arm, mixed with anti-coagulant to prevent blood clotting and pumped into dyalisis machine. 2)In the machine the dialysis is seperated by a partially permeable membrane, blood flows opposite direction to dialysis fluid maintaing concentration gradient 3)Dialysis fluid contains similiar glucose to ensure no net movement of glucose, and similiar ion concentration as blood ensuring that the minerals diffuse if necessary to maintain the correct amount, the fluid has no urea so all urea is extraced by diffusion.