Hemodialysis
In hemodialysis, blood is removed from the body and filtered through a man-made semi-permeable membrane, and is then returned to the body.
The dialyser, also called the artificial kidney, is the key part in hemodialysis which filters the blood.
Dialysate, also known as the dialysis fluid, is a solution consisting of pure water, some electrolytes and so on.
The role of dialysate is to remove toxins from the blood into the dialysate, and at the same time supply patients with some necessary electrolytes. These are done through the process of diffusion, which is possible due to difference in concentration of substances contained in blood and dialysate. Toxins are small in size, thus enabling them to pass from the blood into dialysate through the semi-permeable membrane, whose pores allow only substances smaller than a certain size to pass through (red blood cells, for example, are too big and thus denied entry into the dialysate at the other side of the membrane). Electrolytes are supplied in a similar way. And the loss of useful substances during dialysis can sometimes be prevented.
External pressure may be exerted so as to remove extra fluid. This process is called ultrafiltration.
The role of dialysate is to remove toxins from the blood into the dialysate, and at the same time supply patients with some necessary electrolytes. These are done through the process of diffusion, which is possible due to difference in concentration of substances contained in blood and dialysate. Toxins are small in size, thus enabling them to pass from the blood into dialysate through the semi-permeable membrane, whose pores allow only substances smaller than a certain size to pass through (red blood cells, for example, are too big and thus denied entry into the dialysate at the other side of the membrane). Electrolytes are supplied in a similar way. And the loss of useful substances during dialysis can sometimes be prevented.
External pressure may be exerted so as to remove extra fluid. This process is called ultrafiltration.