Dialysis

Dialysis is the removal of low molecular weight compounds from a colloidal or polymer solution by diffusion through a semipermeable membrane. The solution is poured into a container (dialyzer) with a semipermeable membrane at the bottom (e.g., cellophane). It is placed in another larger container with flowing water. Small molecules and ions pass through the membrane into the water, while colloidal particles and molecules of high molecular weight remain inside. Dialysis occurs slowly. Electrodialysis is faster. In an electrodialyzer, electrodes connected to an external power source are immersed in the flowing water. By passing an electric current, cations from the solution migrate to the cathode, and anions to the anode. Dialysis is the basis for the functioning of an artificial kidney: blood flowing through tubes immersed in special solutions made of semipermeable membranes is cleansed of harmful substances that accumulate in the blood due to kidney dysfunction or poisoning. The cleansed blood is returned to the body.

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė