pinocytosis

pinocytosis:

see endocytosisendocytosis
, in biology, process by which substances are taken into the cell. When the cell membrane comes into contact with a suitable food, a portion of the cell cytoplasm surges forward to meet and surround the material and a depression forms within the cell wall.
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Pinocytosis

the engulfing by the cell surface of fluid and substances that the fluid contains. Pinocytosis is one of the principal mechanisms by which high-molecular-weight compounds enter the cell, particularly proteins and carbohydrate-protein complexes. The phenomenon of pinocytosis was discovered by the American scientist W. Lewis in 1931. During pinocytosis short, slender outgrowths on the plasma membrane surround a drop of fluid. Then the region of the plasma membrane that contains these outgrowths invaginates and pinches off to form a bubble inside the cell. The formation of pinocytotic bubbles, whose diameters do not exceed 2 microns (μ), has been traced by phase-contrast microscopy and microcinematography. With the aid of the electron microscope, bubbles with diameters that range from 0.07 to 0.1 μ can be discerned. Pinocytotic bubbles are capable of freely moving within the cell or of merging with each other or with other intracellular membranous structures. The most active pinocytosis is observed in amoebas, in epithelial cells of the intestines and renal tubules, and in the endothelium of blood vessels and growing oocytes. The level of pinocytotic activity depends on the physiological state of the cell and on the environment. Active inducers of pinocytosis are γ-globulin, gelatin, and certain salts.

T. B. AIZENSHTADT

pinocytosis

[¦pin·ō·sī′tō·səs] (cell and molecular biology) Deprecated term formerly used to describe the process of uptake or internalization of particles, macromolecules, and fluid droplets by living cells; the process is now termed endocytosis.

pinocytosis

[pin″o-si-to´sis] a mechanism by which cells ingest extracellular fluid and its contents; it involves the formation of invaginations by the cell membrane, which close and break off to form fluid-filled vacuoles in the cytoplasm (see accompanying illustration). adj., adj pinocytot´ic.

Mechanism of pinocytosis. Tiny droplets of fluid are trapped by the folds of the plasma membrane and engulfed as fluid-filled vesicles into the cytoplasm.

pin·o·cy·to·sis

(pin'ō-sī-tō'sis, pī'nō-), The cellular process of actively engulfing liquid, a phenomenon in which minute incuppings or invaginations are formed in the surface of the cell membrane and close to form fluid-filled vesicles; it resembles phagocytosis. [pinocyte + G. -osis, condition]

pinocytosis

(pĭn′ə-sĭ-tō′sĭs, -sī-, pī′nə-)n. Introduction of fluids into a cell by invagination of the cell membrane, followed by formation of vesicles within the cells.

pin′o·cy·tot′ic (-tŏt′ĭk) adj.

pin·o·cy·to·sis

(pin'ō-sī-tō'sis) The cellular process of actively engulfing liquid, a phenomenon in which minute incuppings or invaginations are formed in the surface of the cell membrane and close to form fluid-filled vesicles; it resembles phagocytosis. [pinocyte + G. -osis, condition]

PINOCYTOSIS AND EXOCYTOSIS: (Top) Pinocytosis; (Bottom) Exocytosis

PINOCYTOSIS AND EXOCYTOSIS

pinocytosis

(pin″ŏ-sĭ-tō′sĭs, pīn″, -sī″) [ pinocyte + -osis] The process by which cells absorb or ingest nutrients and fluid. An invaginating portion of the cell membrane encircles the nutrient, enclosing it in a membrane-bound sac. The contents of the sac are then digested. See: illustrationillustration

pinocytosis

The process in which cells engulf fluid to form tiny clear spherical containers (vacuoles) which then move through the cell cytoplasm, sometimes acting as scavenging vehicles to be discarded through another part of the cell membrane. Extracellular fluid with dissolved molecules may be moved intracellularly by pinocytosis.

pinocytosis

micropinocytosis

(‘cell-drinking’) the active engulfing of very small particles or liquids by cells; a form of ENDOCYTOSIS. The particles become surrounded by the cell membrane on all sides, which eventually forms a channel from which vesicles are pinched off and move within the PROTOPLASM before their contents can be transferred into the cell proper.

pinocytosis

pin·o·cy·to·sis

pinocytosis

pin•o•cy•to•sis

pinocytosis

pinocytosis:

Pinocytosis

pinocytosis

pinocytosis

pinocytosis

pin·o·cy·to·sis

pinocytosis

pin·o·cy·to·sis

pinocytosis

pinocytosis

pinocytosis

micropinocytosis

pin·o·cy·to·sis

pinocytosis

Words related to pinocytosis

noun process by which certain cells can engulf and incorporate droplets of fluid

Related Words