Concept Explanation: Kidney Failure and Waste Removal

When kidneys fail, they cannot filter nitrogenous wastes (like urea) from the blood. The process used to artificially remove these wastes is called dialysis.

Why Dialysis?

Dialysis mimics the filtering function of healthy kidneys. It uses a semi-permeable membrane to separate wastes from the blood based on diffusion and sometimes osmosis, but the overall procedure is specifically termed dialysis.

Step-by-Step Reasoning:

Step 1: Identify the key problem - removal of nitrogenous wastes during kidney failure.

Step 2: Recall that osmosis involves water movement across a membrane, plasmolysis is shrinkage of cells in hypertonic solutions, and diffusion is passive movement of particles. These are processes, but not the medical procedure.

Step 3: Dialysis is the clinical technique where blood is passed through a dialyzer; wastes diffuse out of the blood into a dialysate fluid, while essential substances are retained.

Final Answer: dialysis.

Related Topics & Formulae:

Diffusion: Movement of particles from high to low concentration. Fick's law: $J=-D\frac{d\varphi }{dx}$, where J is flux, D is diffusion coefficient, and $\frac{d\varphi }{dx}$ is concentration gradient.

Osmosis: Water movement across a semi-permeable membrane. Osmotic pressure: $\pi =iCRT$, where i is van't Hoff factor, C is concentration, R is gas constant, T is temperature.

Plasmolysis: Occurs in plant cells when water leaves the cell due to osmosis in a hypertonic solution, causing the membrane to pull away from the cell wall.

Dialysis: Relies on diffusion across a membrane. The rate of removal depends on the concentration gradient of wastes between blood and dialysate.