kidney failure

• Presence of blood cells or protein in urine = kidney disease
• biuret reagent = test for protein
• biuret reagent:

  present colour change = blue -> violet
• how can kidney failure be treated?

  dialysis or kidney transplant
• where can someone get a kidney transplant from

  a donor of a similar tissue type to themselves
• donor kidney may be rejected by body -> attacked by immune system UNLESS immunosuppressant drugs taken
• immunosuppressant drugs suppress the immune system
• what does dialysis involve?

  filtering and cleaning the blood
• Process of dialysis:

  1. blood is removed from patient
  2. pumped by blood pump
  3. blood clots prevented by anti-coagulant
  4. flows into dialysis machine -> separated from dialysis fluid by semi-permeable membrane
  5. no net movement of useful substances
  6. excess salts diffuse into dialysis fluid
  7. dialysis fluid has no urea so diffuses from higher concentration in blood to lower concentration in dialysis fluid
  8. counter current flow to maintain a concentration gradient
  9. clean blood returned to patient
  10. waste dialysis fluid removed
• why is waste dialysis fluid removed?

  to prevent equilibrium occurring with uncleaned blood
• what does an anti-coagulant do?

  prevent blood clots
• the dialysis fluid contains the same concentration of glucose and amino acid as the blood to ensure that diffusion of these useful substances do not occur -> no net movement
• diffusion of urea, excess salts and water occurs across the whole of the machine because it maintains a concentration gradient
• advantage of kidney transplants?

  can lead a normal life after operation
• advantages of dialysis?

  available straightaway and no immunosuppressant drugs need to be taken
• disadvantages of kidney transplants?

  immunosuppressant drugs must be taken

  donor kidneys last around 8 years

  can be hard to find donors -> tissue typing needed
• why must immunosuppressant drugs be taken (kidney donors)

  to minimise risk of rejection
• disadvantages of dialysis?

  expensive for NHS

  limited diet (protein + salt)

  regular dialysis sessions -> impact on patients lifestyle