Section 3: Waste Products of Body functions are removed by the Kidneys
How does a kidney work?
What can be done if the system does not function?
Candidates should:
(i) Know that kidney failure may be treated by a transplant or by a dialysis machine and compare the advantages and disadvantages of the use of these methods.
(j) Know that a diseased kidney may be replaced by a healthy one by transplant from a donor of a similar 'tissue type' to the recipient. The donor kidney may be rejected, attacked by the immune system, unless anti-rejection drugs are taken.
(k) Understand that in a dialysis machine a person's blood flows between selectively permeable membranes. It is important that useful substances in the blood, such as glucose and salts, are not lost. To prevent this, the dialysis fluid contains the same concentration of these substances as blood plasma. This ensures that only urea and excess salts and water diffuse into the dialysis fluid. This treatment has to be carried out at regular intervals.
Candidates should:
(b) Understand that immunisation can be used to protect humans from infectious disease although it raises dilemmas for individuals and for society. Evaluate the factors influencing parents in decisions about whether to have children vaccinated or not including the roles of scientific evidence and public opinion. This indicates a moral responsibility which may ultimately be outside the scope of science.
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