Which process is primarily responsible for removing excess water from the blood during dialysis?

Which process is primarily responsible for removing excess water from the blood during dialysis?

• A. Ultrafiltration
• B. Osmosis
• C. Diffusion
• D. Active transport

Answer: (A)

Ultrafiltration is the process that removes excess water during dialysis. It uses a hydrostatic pressure gradient across the dialysis membrane to push plasma water from the blood into the dialysate. The machine controls the ultrafiltration rate to achieve the target fluid removal, based on the patient’s dry weight and tolerance. Osmosis involves water movement in response to solute differences, but it’s not the primary mechanism used to remove fluid in dialysis. Diffusion moves solutes (like urea) along concentration gradients, not primarily water. Active transport requires cellular energy and isn’t a mechanism driving fluid removal in dialysis.

Ultrafiltration is the process that removes excess water during dialysis. It uses a hydrostatic pressure gradient across the dialysis membrane to push plasma water from the blood into the dialysate. The machine controls the ultrafiltration rate to achieve the target fluid removal, based on the patient’s dry weight and tolerance.

Osmosis involves water movement in response to solute differences, but it’s not the primary mechanism used to remove fluid in dialysis. Diffusion moves solutes (like urea) along concentration gradients, not primarily water. Active transport requires cellular energy and isn’t a mechanism driving fluid removal in dialysis.