Question

Describe the general processes involved in hemodialysis therapy including the two concentration gradients that act independently between blood plasma & the dialysis fluid.

Answer 1

Hemodialysis is a process to artificially purify blood when kidneys are not working. In this procedure, the blood is taken out from a opening in body and made to enter in a dialysis machine. Blood flows inside the machine through network of tubes. Around the tubes, hemodialysis fluid flows. The direction of flow of blood is opposite to follow of dialysis fluid. This creates a concentration gradient for movement of solutes and other impurities (like urea, potassium, creatinine etc).

The dialysis fluid doesn't contain any impurities like there in plasma. This creates a concentration gradient of solutes between dialysis fluid and plasma. This gradient cause movement of impurities from plasma to dialysis fluid and in this way blood is purified.