Kidney dialysis is a treatment that artificially replicates the behaviors of the kidneys. The kidneys are a vital piece in the renal system and the overall operation of the human body. Among other functions kidneys take part in the disposal of waste and excess fluids within the body; they process and balance necessary chemicals and substances; and they assist in the functions that produce red blood cells. When disease, injury, or post-operation difficulty breaks down kidney functioning to typically under 30%, dialysis is given in order to make up for the loss of the kidneys’ natural processes.
There are a variety of ways by which a patient may be administered kidney dialysis. These include hemodialysis, hemofiltration, and peritoneal dialysis. Hemodialysis is a process which uses an apparatus outside the body known as the hemodialyzer to filter blood and remove excesses. Similarly, hemofiltration uses an external apparatus; however this procedure implements a pressure gradient and subsequently clears more substances. Through the use of a catheter, peritoneal dialysis utilizes a fluid called dialysate to absorb excess waste matter and substances within the body, cleaning the blood internally.
The core usage of kidney dialysis is just the removal of superfluous materials and fluids from the blood through diffusion as well as ultrafiltration. Diffusion pertains to a common trait of substances within a fluid to move from highly-concentrated areas to lowly-concentrated ones. One example of this common attribute is the phenomenon that occurs when a drop of dye is distributed into a glass of water. The dye then spreads out and permeates the water evenly. Another instance of this event happens when sugar is mixed into coffee. The sugar then disintegrates and spreads equally throughout the liquid.
The second principle of dialysis, ultrafiltration, occurs when liquids are filtered through several semi-permeable membranes by hydrostatic pressure; the membranes catch larger solids and solutes while others pass through the filters. In certain types of dialysis, this happens through osmotic pressure. In a manner similar to ultrafiltration, common water filters, such as the kind applied to a household tap, work to filter out unwanted solids and substances and produce cleaner water.
Together, these transport processes work much like a water filter in an aquarium to remove excess chemicals, waste, and fluids in the procedure of dialysis. You can find more information and additional resources on kidney failure at The National Kidney Foundation, which can be found here.