Life Processes — Science STD 10 — Question

The artificial kidney contains tubes made of cellophane with a semi-permeable lining. These tubes are suspended in a tank filled with a dialyzing solution. This fluid contains water and glucose in concentrations similar to those in blood. These tubes are selectively permeable and allow only certain substances to pass through them. Blood is then passed through the semi-permeable coiled cellophane tubes. The tubes allow small molecules such as urea, creatinine and uric acid to pass out.
Metabolic wastes are also filtered out in the surrounding solution. Macromolecules such as proteins are retained in the blood. Purified blood is then mixed with antiheparin and warmed to the body temperature. The purified blood is returned through a vein in the same arm. The function of dialysis is similar to the function of the kidney, but the only difference is that there is no reabsorption during dialysis.