Ultrafiltration

separation of corpuscular or higher molecular weight substances as a function of the pore size of the filter membrane by applying hydrostatic pressure and recovering large quantities of the filtered liquid.

In the glomeruli of the kidney, a U. up to a molecular weight (MG) of about 5,000, limited permeability still exists for substances up to 50,000, apart from fragments, proteins are not filtered as they have at least an MG of about 75-100,000.

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