Science — AI-generated practice question

Artificial Kidney: An artificial kidney is a device used to remove nitrogenous waste products (such as urea) from the blood when the kidneys fail. This process is called haemodialysis.

Principle: It works on the principle of dialysis (diffusion through a semi-permeable membrane). The device contains tubes with a semi-permeable lining suspended in dialysing fluid, which has the same osmotic pressure as blood but is devoid of nitrogenous wastes. The patient's blood is passed through these tubes, and waste products diffuse from the blood into the dialysing fluid. The purified blood is then pumped back into the patient. Unlike the kidney, no reabsorption is involved.

Source: Chapter 5, Section 5.5.1 (More to Know — Artificial Kidney)

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• Examiners expect two parts: definition (what it is) and principle (how it works).
• Key terms to include: dialysis, semi-permeable membrane, diffusion, dialysing fluid, no reabsorption.
• Mentioning that dialysing fluid lacks nitrogenous wastes (creating a concentration gradient for diffusion) is a scoring point.
• The last line about no reabsorption distinguishes it from a natural kidney — include it for full marks.