Hemodialysis – Class 11 | Chapter – 19 | Biology Short Notes Series PDF

Hemodialysis: The kidney is one of the most important organs of a human which actively takes part in the excretion process of the human body. Due to some specific reasons, this kidney becomes damaged and fails to do its function. What will happen if the municipality workers are not coming to clean our streets for a week? We can see heaps of wastes here and there around the street. The same happens when our kidney fails to function. Wastes that were cleared out of our body by the kidney, would start to accumulate in our body. This is a serious health issue.

The Kidney would stop completely functioning if it is affected by a chronic kidney disease which leads to chronic renal failure. On this condition, doctors would have two solutions for the patient: either dialysis or renal transplantation. Renal transplantation is suggested in the worst situations alone and dialysis is a common solution to renal failure.

Hemodialysis simply refers to the process in which an artificial kidney (dialyzer) does the function of a kidney when a person’s natural kidney fails to do that. When trying to understand, this definition, keep two things in mind:

  • Kidneys not only remove end-products of different metabolic processes but also produce certain hormones for our body. The artificial kidney doesn’t do that but those hormones are injected into the person’s body as a part of the treatment.
  • An artificial kidney or Dialyzer is a machine that is kept outside our body and is connected through our veins for its functioning.

Dialyzer, an electric device, would receive the blood from our body. This blood is filtrated through a filter and after removing the waste products, the blood is pumped back to the human body. By this process, the waste and extra fluid in the blood is removed and the blood pressure level is regulated.

Dialysis works mainly on two principles: the principle of diffusion and the principle of ultrafiltration. The principle of diffusion works by allowing a solution to pass ove a semipermeable membrane for dialysis. But in the principle of ultrafiltration, both the solute passing and fluid waste removal are done under a pressure guardian.

Procedure of Hemodialysis

Hemodialysis Process

To perform Hemodialysis, we mainly need four things- a Dialyzer (artificial kidney), dialysate (a solution), a blood delivery system, and access to our blood vessels. The dialyzer plays the major role of filtering the blood; but let us begin from where the actual process begins i.e., from the access to the blood vessels.


Access to a human body vessel can be done in three ways- through a fistula, graft, or rarely through a catheter (a soft tube inserted into a large vein into the neck or chest). This selection depends on the nature of the patient’s body. This access may be placed as a part of your body, through minor surgery.

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By Team Learning Mantras