Haemodialysis and Kidney Failure — NEET Biology

Correct answer: B — S1, S3, and S4 are correct

The core concept here is the mechanism and components of hemodialysis. S1: "Blood drained from a convenient artery is pumped into a dialysing unit after adding an anticoagulant like heparin." This statement is correct. S2: "The unit contains a coiled cellophane tube surrounded by a fluid (dialysing fluid) having the same composition as that of plasma except the nitrogenous wastes." This statement is incorrect because the dialysing fluid lacks nitrogenous wastes, which is crucial for creating the concentration gradient for their removal. S3: "The porous cellophane membrance of the tube allows the passage of molecules based on concentration gradient." This statement is correct, as the cellophane acts as a selective barrier. S4: "The cleared blood is pumped back to the body through a vein after adding anti-heparin to it." This statement is correct, as anti-heparin neutralizes the anticoagulant effect before returning blood to the body. S5: "Kidney transplantation is the ultimate method in the correction of acute renal failures (kidney failure)." Hemodialysis is a treatment, not a permanent cure like kidney transplantation. This statement is incorrect. Therefore, statements S1, S3, and S4 are correct.