osmosis


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Related to osmosis: reverse osmosis, diffusion

osmosis

 [oz-mo´sis, os-mo´sis]
the diffusion of pure solvent across a membrane in response to a concentration gradient, usually from a solution of lesser to one of greater solute concentration. adj., adj osmot´ic.

The process of osmosis and the factors that influence it are important clinically in the maintenance of adequate body fluids and in the proper balance between volumes of extracellular and intracellular fluids.

The term osmotic pressure refers to the amount of pressure necessary to stop the flow of water across the membrane. The hydrostatic pressure of the water exerts an opposite effect; that is, it exerts pressure in favor of the flow of water across the membrane. The osmotic pressure of the particles in a solute depends on the relative concentrations of the solutions on either side of the membrane, and on the area of the membrane. The osmotic pressure exerted by the nondiffusible particles in a solution is determined by the numbers of particles in a unit of fluid and not by the mass of the particles.
If the solution surrounding a cell has the same solute concentration as the internal environment of the cell (isotonic), the flow rates in and out of the cell are the same, and the cell remains the same size. If the solute concentration outside the cell is lower (hypotonic), more water will flow into the cell than out, and the cell will swell and perhaps burst. If the solute concentration outside the cell is greater (hypertonic), more water will flow out of the cell than into it, and the cell will shrivel.
Demonstration of osmotic pressure on the two sides of a semipermeable membrane.

os·mo·sis

(os-mō'sis),
The process by which solvent tends to move through a semipermeable membrane from a solution of lower to a solution of higher osmolal concentration of the solutes to which the membrane is relatively impermeable.
[G. ōsmos, a thrusting, an impulsion]

osmosis

(ŏz-mō′sĭs, ŏs-)
n. pl. osmo·ses (-sēz)
1.
a. Diffusion of fluid through a semipermeable membrane from a solution with a low solute concentration to a solution with a higher solute concentration until there is an equal solute concentration on both sides of the membrane.
b. The tendency of fluids to diffuse in such a manner.
2. A gradual, often unconscious process of assimilation or absorption: learned French by osmosis while residing in Paris for 15 years.

os·mot′ic (-mŏt′ĭk) adj.
os·mot′i·cal·ly adv.

os·mo·sis

(oz-mō'sis)
The process by which solvent tends to move through a semipermeable membrane from a solution of lower to a solution of higher osmolal concentration of the solutes to which the membrane is relatively impermeable.
[G. ōsmos, a thrusting, an impulsion]

osmosis

(oz-mō′sĭs) [Gr. osmos, impulse, + osis, condition]
Enlarge picture
OSMOSIS
The passage of solvent through a semipermeable membrane that separates solutions of different concentrations. The solvent, usually water, passes through the membrane from the region of lower concentration of solute to that of a higher concentration of solute, thus tending to equalize the concentrations of the two solutions. The rate of osmosis is dependent primarily upon the difference in osmotic pressures of the solutions on the two sides of a membrane, the permeability of the membrane, and the electric potential across the membrane and the charge upon the walls of the pores in it. See: illustration

reverse osmosis

A form of water treatment that removes infectious particles and dissolved ions more effectively than other water purification techniques. Water so purified can be used in hemodialysis.
osmotic (oz-mot′ik), adjectiveillustration

osmosis

The automatic movement of the fluid part of a solution through a membrane, separating two quantities of the solution, in such a direction as to dilute the solution of higher concentration. The membrane is permeable to the liquid but not to the dissolved substance. Such a membrane is said to be semipermeable and membranes of this kind occur widely in the body. Osmosis is an important principle on which much of physiology is based.

osmosis

the movement of a solvent (water in biological systems) through a differentially permeable membrane from a solution with high water concentration and low solute concentration, to one with a low water concentration and high solute concentration.

osmosis 

A passive process of movement of water through a semipermeable membrane in response to a concentration gradient, from an area of low solute (e.g. glucose molecules) concentration (i.e. high water concentration) to one of high solute concentration (i.e. low water concentration). The membrane is permeable to water but relatively impermeable to solutes. See osmotic pressure; hypertonic solution.

os·mo·sis

(os-mō'sis)
Process by which solvent tends to move through a semipermeable membrane from a solution of lower to a solution of higher osmolal concentration of solutes to which membrane is relatively impermeable.
[G. ōsmos, a thrusting, an impulsion]
References in periodicals archive ?
That means the company may install another SIRION Mega Reverse Osmosis system in its facility to ensure it has a steady and reliable source of high-purity water, which is key to producing more of its craft brews with consistency and repeatability, according to Rowe.
In crossflow filtration, an incoming feed stream passes across the surface of a crossflow membrane, and two exiting streams are generated: a permeate stream (which passes through the membrane) and a retentate stream (which is retained by the membrane.) In crossflow filtration the permeate stream is the target stream (i.e., the filtered wine), whereas in reverse osmosis, the streams are split, something is done to one stream and then the two are put back together, altered by the "treatment."
The reason osmosis stops is that the pressure inside the osmometer increases and counteracts the tendency for osmosis.
Positioned in the growing seawater desalination markets of the Middle East, this joint venture intends to distribute reverse osmosis membrane elements for seawater desalination not only in Saudi Arabia but also in other regions of the Middle and Near East as well as in the countries of North Africa.
Conventional reverse osmosis membranes operating on landfill leachate have a typical lifespan of less than one year.
REF: B IS NAVSEA LETTER 5ER 394B/0836 RECOMMENDING THE REMOVAL OF THE MANUAL REVERSE OSMOSIS DESALINATOR FRON 688 AND 774 CLASS SUBMARINES.
GE provided its seawater reverse osmosis (SWRO) membrane technology to a new water treatment plant, which can now produce 200,000 imperial gallons per day of desalinated water.
Particulate and organic matter fouling of seawater reverse osmosis systems; characterization, modelling and applications.
Recycling plant consists of 2 x 80 m3/h ultra filtration, 2 x 60 m3/h stage 1 reverse osmosis, 2 x 10 m3/h stage 2 reverse osmosis and 30 m3/h mixed bed .The High quality water from the reverse osmosis and mixed bed systems are used for paint shop and manufacturing purposes.
Modern Water expects to achieve greater than 30 per cent energy savings at a forward osmosis (FO) desalination plant it is building in Oman and which is billed as the world's first fully commercial facility of its kind.
Their technique is based on the process of osmosis - the natural movement of water from a region with low solute concentration across a permeable membrane to a region with high concentration.