What does peritoneal dialysis utilize as its semipermeable membrane?

Peritoneal dialysis utilizes the peritoneum as its semipermeable membrane. This is a significant aspect of the procedure since the peritoneum, which is a thin layer of tissue lining the abdominal cavity and covering the organs within it, allows for the exchange of fluids and solutes between the blood and the dialysis solution introduced into the peritoneal cavity.

In peritoneal dialysis, the dialysis fluid is instilled into the abdominal cavity through a catheter, and waste products and excess fluids are drawn from the blood across the peritoneal membrane into the dialysis fluid. This method effectively removes toxins and excess electrolytes, functioning similarly to how the kidneys operate to filter blood.

The other options do not fulfill the role of a semipermeable membrane in this context. The skin is not involved in the dialysis process; while the lining of the stomach refers specifically to the gastric mucosa and does not serve in dialysis; the bladder's function is to store urine, and it is not a site for dialysis. Thus, the peritoneum is uniquely suited for this process, making it the correct answer.