Peritoneal dialysis uses what as the filter?

• A. The liver
• B. An artificial kidney machine
• C. The lining of the peritoneal cavity
• D. The lungs

Answer: (C)

The filter is the lining of the peritoneal cavity, the peritoneum. This thin, highly vascular membrane covers the abdominal organs and, when dialysate is placed into the cavity, waste products and excess fluids move across its membrane by diffusion and osmosis. The blood vessels in the peritoneum allow urea, creatinine, electrolytes, and fluids to pass into the dialysis solution, which is then drained away, removing those wastes from the body. The dialysate often contains glucose to create an osmotic gradient that helps pull extra fluid out. This method uses the body's own lining as the filter, unlike hemodialysis, which relies on an artificial kidney machine. The liver or lungs do not perform this filtration in peritoneal dialysis.