in Excretory Products and their Elimination (Urinary System) by

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  1. The failure of both kidneys due to injury or disease leads to death of a person because of accumulation of excess of potassium in blood which affects the functioning of the heart.
  2. This condition can be relieved by the use of hemodialysis (Artificial Kidney), i.e. by filtration of blood.
  3. Dialysis involves separating large non-diffusible particles from smaller diffusible ones by using a semi-permeable membrane.
  4. In a dialysis machine, blood is pumped from the radial artery in the arm of the patient through a coiled cellophane tube and then returned to a vein in the same arm.
  5. The cellophane tube is immersed in a dialyzing solution, containing regulated amount of dissolved salts, sugar, pH, etc.
  6. Since the dialyzing solution contains no waste and the cellophane tubing is differentially permeable, substances like salts, sugars, urea, etc. can diffuse out from the patient’s blood into the solution.
  7. The diffusion gradient for any solution can be controlled by dissolving more or less of that substance in the dialyzing solution.
  8. Excess water is removed by artificially increasing the blood pressure in the cellophane tubing.

In this way, the process of hemodialysis is carried out. The kidney machine performs the function of the nephron. Dialysis is performed twice a week, for about 12 hours.

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