kidney failure

• advantages of transplants:

  • people can lead normal life without watching diet
  • cheaper for NHS
• disadvantages of transplants:

  • shortage of organ donors
  • kidneys last 8-9 years
  • operation is risky
  • must take immune-suppressnt drugs which increase change of infection
• dialysis:

  • unfiltered blood high in urea mixed with blood thinners to prevent clotting
  • pumped inside dialysis mahine
  • blood and dialysis fluid seperated by partially permeable membrane
  • blood and dialysis fluid in opposite direction
  • allows exchange of substances at concentration gradient
• dialysis fluid contains:

  • glucose concentration similar to normal level of healthy blood
  • prevents movement of glucose across membrane because there is no concentration gradient
  • patients retain glucose for respiration
• • dialysis fluid has no urea
  • so, there is large concentration gradient
  • so, urea moves from blood to dialysis fluid by diffusion across partially permeable membrane
• • dialysis fluid contains ion concentration similar to healthy blood plasma
  • blood is too low in ions - ions diffuse from dialysis fluid into blood
  • blood is too high in ions - ions diffuse from blood to dialysis fluid
• advantages of dialysis:

  • available to all kidney patients
  • no need for immune-suppressant drugs
  • can buy time until donor organ found
• disadvantages of dialysis:

  • sessions are long and regular - impact on lifestyle
  • can cause blood clots or infection
  • expensive for NHS
  • limitation of salt and protein intake between sessions