Blood filtration via diffusion across semipermeable membrane (null)

Blood filtration via diffusion across a semipermeable membrane refers to the physical process by which certain molecules or ions are separated from blood based on their size and concentration gradients. This occurs naturally in the kidney's glomerulus—where hydrostatic pressure forces water and small solutes through the glomerular capillary wall into Bowman’s capsule while larger proteins remain in the bloodstream due to selective permeability[2][3][4]. In medical treatments such as hemodialysis or hemofiltration for kidney failure, an artificial semipermeable membrane is used outside the body. Blood flows on one side of this membrane while dialysate flows on the other; waste products diffuse out of the blood into dialysate due to concentration gradients, mimicking natural renal function[5][6]. The process relies on passive transport mechanisms—primarily diffusion for small solutes and osmosis for water movement—rather than specific molecular targets like receptors or enzymes. Note: This entry does not correspond to a single molecule/receptor but rather describes a physiological/engineering principle used in both biological systems (glomerular capillary wall) and medical devices (dialyzer membranes). It is not considered a therapeutic "target" in pharmacology but rather an engineered filter system or natural barrier. Therefore, is_target should be marked as false and is_incorrect as true for purposes where only discrete molecular targets are valid entries.

Other names

Blood filtrationDiffusion across semipermeable membraneDialysis filtrationHemodialysis processGlomerular filtration (context-dependent)

Physical separation by size and concentration gradient (diffusion/osmosis) Selective permeability to small solutes and water while retaining larger molecules like proteins and blood cells[1][2][3][4][5]