Explain the principle of dialysis with the help of a labelled diagram.

In the process of dialysis, the blood from an artery in the patient’s arm is taken and is made to flow into the dialyser of a dialysis machine. The dialyser is made of long tubes of selective permeable membrane (like cellulose) which are coiled in a tank containing dialysing solution. The dialysing solution is a mixture of water, glucose and salts present in same concentrations as those of normal blood. As the blood passes through the dialysing solution most of the wastes like urea present in it pass through the selectively permeable cellulose tubes into the dialyzing solution. The purified blood is then pumped back into a vein of the patient’s arm.