Pinocytosis
In cellular biology, pinocytosis ("cell-drinking", "bulk-phase pinocytosis", "non-specific, non-adsorptive pinocytosis") is a form of endocytosis in which small particles of liquids are brought into the cell suspended within small vesicles which subsequently fuse with lysosomes to hydrolyze, or to break down, the particles. This process requires adenosine triphosphate (ATP), the chemical compound used as energy in a majority of cells. Pinocytosis is primarily used for the absorption of extracellular fluids (ECF), and in contrast to phagocytosis, generates very small vesicles. Unlike receptor-mediated endocytosis, pinocytosis is unspecific in the substances that it transports. The cell takes in surrounding fluids, including all solutes present. Pinocytosis also works as phagocytosis, the only difference is that phagocytosis is specific in the substances it transports. Phagocystosis actually engulfs whole food particles,which are later broken down by enzymes and absorbed into the cells. Pinocytosis, on the other hand, is when the cell engulfs already dissolved/broken down food.
Non-specific, adsorptive pinocytosis is also called receptor-mediated endocytosis.
References
Campbell, Reece, Mitchell: "Biology", Sixth Edition, Copyright 2002 P.151
Marshall, Ben, Incredible Biological Advancements of the 20th Century, Copyright 2001 p899
The author says: "Non-specific, adsorptive pinocytosis is also called receptor-mediated endocytosis."
But receptor-mediated endocytosis is NOT the same as pinocytosis. Receptor-mediated endocytosis is SPECIFIC in its engulfing of molecules that bind to the receptors on the cell membrane, whereas pinocytosis is NON-SPECIFIC, meaning it takes in random extracellular fluid. The author makes this distinciton in the article itself!
See also
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