Explain the principle of haemodialysis.

Haemodialysis serves as a substitute for kidney. It works on the principle of diffusion. The nitrogenous wastes (urea), creatinine and potassium ions diffuse out into the dialyzing fluid across the semi-permeable membranes along the concentration gradient (from high concentration to low concentration). It corrects electrolyte imbalance and removes waste from the body.