What does pinocytosis mean?
Pinocytosis is the cellular process of taking in extracellular fluid and the dissolved substances it contains. A cell membrane folds inward to form small, membrane-bound vesicles, bringing fluid and dissolved molecules into the cell before the vesicles join with internal membranes or release their contents. The process is especially associated with the absorption of proteins, lipids, and other soluble materials. Pinocytosis belongs to the broader category of endocytosis, which includes several specialized forms of cellular uptake. It differs from phagocytosis, often described as cellular eating, because phagocytosis primarily engulfs solid particles rather than taking in fluid. Pinocytosis also differs from receptor-mediated endocytosis, which concentrates particular molecules through their binding to membrane receptors; ordinary pinocytosis is sometimes called fluid-phase endocytosis. The name reflects the basic image of a cell drinking: the membrane encloses a small quantity of external fluid and carries it inward.
nounThe uptake of extracellular fluid and its dissolved substances by a cell through the formation of small membrane-bound vesicles. It is a form of endocytosis, often contrasted with phagocytosis, in which solid particles are engulfed.
- The process by which a cell takes in extracellular fluid and dissolved substances through the formation of small membrane-bound vesicles.
"The renal cells absorbed the filtered proteins by pinocytosis."
"Fat cells use pinocytosis to absorb lipids from the surrounding fluid."
"The microscope revealed extensive pinocytosis at the surface of the cultured cells."
The standard plural of pinocytosis.
"Different types of pinocytoses transport distinct groups of dissolved substances."
Pinocytosis is cellular drinking: cells form microscopic bubbles of membrane to take in droplets of fluid.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does pinocytosis come from?
Pinocytosis is a modern scientific word formed from Greek roots meaning “drinking” and “cell,” with an ending referring to a cellular process. It was developed by analogy with phagocytosis, whose name similarly combines an action with the suffix associated with cells. The Greek element kytos, meaning “cell,” also underlies related scientific terms such as cytology and cytoplasm.
Related word forms
How pinocytosis is actually used
This is a technical term in cell biology and medicine. It is also informally called cellular drinking, but that expression is explanatory rather than preferred in formal scientific writing.
Easily confused with pinocytosis
Pinocytosis takes in extracellular fluid and dissolved substances, whereas phagocytosis engulfs relatively large solid particles.
Endocytosis is the broader process that includes pinocytosis and other forms of vesicle-mediated cellular uptake.