Why do some people need to use a dialysis machine ? Explain the principle involved
in it.
A. Dialysis machine is used to filter the blood of a person when two kidneys are damaged.
The process is called ‘haemodialysis’.
Principles involved in the process :
- In this process blood is taken outrfrom the main artery, mixed with an anticoagulant such as heparin and then pumped into the apparatus called dialyzer.
- In this apparatus blood flows through channels or tubes. These tubes are embedded in the dialyzing fluid.
- The membrane separates the blood flowing inside the tube and dialyzing fluid, which has the same composition as that of plasma, except the nitrogenous wastes.
- The patients blood is passed through the tubes, during this passage the waste products from the blood pass into dialysing fluid by diffusion.
- This process is called dialysis.
- The purified blood is pumped back into the patient through a vein. This is similar to the function of kidney but it is different since there is no reabsoprtion involved.
- Each dialysis session lasts for 3 to 6 hours. This method has been using for thousands of uremic/kidney failure patients all over the world.
Principle : Dialysis machine works on the principles of the diffusion of solutes and
ultrafiltration of fluid across a semipermeable membrane.
