In medical technology, the term “artificial kidney” commonly refers to which of the following used in the treatment of kidney failure?

Introduction:
When the kidneys fail to adequately filter waste products from the blood, artificial methods are required to perform their function. In this context, the phrase artificial kidney is often used in textbooks and hospitals. Understanding what this term actually refers to is important for basic medical awareness. This question asks you to choose the correct description of an artificial kidney from several possibilities involving real organs and medical equipment.

Given Data / Assumptions:
- The term artificial kidney is used in relation to kidney failure. - Options include a transplanted donor kidney, a machine, another person's kidney and the patient's other kidney. - We assume standard terminology used in nephrology and medical textbooks. - The focus is on artificial devices, not natural organs.

Concept / Approach:
The artificial kidney refers to a dialysis machine used in haemodialysis. This machine takes over part of the filtering role of the kidneys by removing waste products, excess salts and extra water from the blood through a semipermeable membrane. Blood is drawn from the patient, passes through the dialyser and is then returned to the body. A transplanted kidney, whether from a live or deceased donor, is a natural organ, not a mechanical device, and is therefore not called an artificial kidney. Similarly, the patient's own remaining kidney is natural. Thus, the correct answer is the dialysis machine used for haemodialysis.

Step-by-Step Solution:
Step 1: Recall that in kidney failure, patients often undergo haemodialysis to remove urea and other wastes from the blood. Step 2: Recognise that the machine used for haemodialysis is designed to mimic the filtration function of kidneys and is commonly called an artificial kidney. Step 3: Distinguish between natural organs and artificial devices. A transplanted kidney is still a biological organ, not an artificial machine. Step 4: Understand that temporarily connecting another person's kidney is not a standard or practical treatment option; transplantation involves permanent surgical placement. Step 5: Note that the patient's other normal kidney is part of the body and is not referred to as artificial. Step 6: Conclude that the dialysis machine is the artificial kidney in medical terminology.

Verification / Alternative check:
Nephrology textbooks describe haemodialysis in detail, emphasising that the dialyser in the machine functions as an artificial kidney by allowing diffusion of waste products across a semipermeable membrane into dialysing fluid. Patient education materials and hospital brochures frequently use the phrase artificial kidney machine to explain dialysis. In contrast, transplant surgery literature always refers to donor kidneys and transplanted kidneys as natural organs, never as artificial kidneys. This confirms that the dialysis machine is the correct answer.

Why Other Options Are Wrong:
A transplanted donor kidney: A biological organ from another person; it is not mechanical and is not called an artificial kidney. Another person's kidney temporarily connected: Not a recognised or standard medical procedure and not described as an artificial kidney. The patient's other normal kidney in the same body: This is a natural kidney, not a device; calling it artificial would be incorrect.

Common Pitfalls:
Some learners confuse artificial kidney with kidney transplantation because both are treatments for renal failure. Others may think that any kidney replaced or added is artificial. To avoid this confusion, remember that artificial in this context refers to man made machines, not transplanted biological organs. Haemodialysis machines and their dialysers are therefore artificial kidneys, while transplants involve natural donor kidneys.

Final Answer:
The artificial kidney is A dialysis machine used to filter blood in patients with kidney failure.