Which term describes the diffusion driving force across the dialysis membrane?

Which term describes the diffusion driving force across the dialysis membrane?

• A. Temperature gradient
• B. Pressure gradient
• C. Electrical gradient
• D. Concentration gradient

Answer: (D)

The movement of solutes across the dialysis membrane by diffusion is driven by a concentration gradient. Solutes diffuse from the blood side, where their concentration is higher, to the dialysate side, where their concentration is lower, until the two sides approach equilibrium. This concentration difference is the force that pushes solutes like urea, creatinine, and excess electrolytes across the membrane. Temperature can influence how fast diffusion happens, but it doesn’t define the driving force. A pressure gradient governs ultrafiltration (fluid removal), not the diffusion of solutes. Electrical gradients can affect charged particles, but the fundamental driver for diffusion in dialysis is the concentration gradient.

The movement of solutes across the dialysis membrane by diffusion is driven by a concentration gradient. Solutes diffuse from the blood side, where their concentration is higher, to the dialysate side, where their concentration is lower, until the two sides approach equilibrium. This concentration difference is the force that pushes solutes like urea, creatinine, and excess electrolytes across the membrane. Temperature can influence how fast diffusion happens, but it doesn’t define the driving force. A pressure gradient governs ultrafiltration (fluid removal), not the diffusion of solutes. Electrical gradients can affect charged particles, but the fundamental driver for diffusion in dialysis is the concentration gradient.