Kidney failure

• Kidney failure can be identified by looking at if there is protein in the urine or blood in the urine.
• If the kidneys fail, the concentrations of urea and mineral ions build up, causing:

  • build-up of toxic urea in the blood
  • high blood pressure
  • loss of electrolyte balance
  • weakened bones
  • pain and stiffness in the joints
  • anemia
• Glomerular filtration rate (GFR) = the rate at which blood is filtered
• The GFR is used to indicate kidney disease. It tells us creatinine levels.
• Peritoneal dialysis = done inside the body, it makes use of the natural dialysis membranes formed by the lining of the abdomen, the peritoneal.
• Transplants:

  • risk of rejection (immunosuppressants- increased susceptibility to infectious disease)
  • shortage of donor kidneys
  • transplanted organs don't last forever
• Transplants:

  • free from the restrictions that come with regular dialysis sessions and dietary monitoring
• Dialysis:

  • much more readily available than donor organs
  • patients can lead a relatively normal life
• Dialysis:

  • patients have to monitor diet carefully
  • patients need regular dialysis sessions
  • long-term dialysis is much more expensive than a transplant and can eventually cause damage to the body
• An artificial partially permeable membrane is used in dialysis machines between the blood and dialysis fluid so that smaller substances (glucose, ions, water and urea) can diffuse through but larger molecules like plasma proteins cannot and will remain in the blood.
• There is no urea in dialysis fluid to ensure the maximum amount of urea diffuses out of the blood.
• There is the same amount of mineral ions and glucose in dialysis fluid as there is in healthy blood. This allows excess ions/glucose to diffuse into the dialysis fluid if needed or more ions/glucose to diffuse into the blood.
• The blood and dialysis fluid flow in opposite directions to maintain a steep concentration gradient.
• Diffusion not active transport is used in a dialysis machine as it is an artificial membrane so there are no mitochondria or pumps.