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Osmolarity is affected by changes in water content, as well as temperature and pressure. In contrast, osmolality is independent of temperature and pressure. For a given solution, osmolarity is slightly less than osmolality, because the total solvent weight (the divisor used for osmolality) excludes the weight of any solutes, whereas the total ...
Osmotic concentration, formerly known as osmolarity, [1] is the measure of solute concentration, defined as the number of osmoles (Osm) of solute per litre (L) of solution (osmol/L or Osm/L). The osmolarity of a solution is usually expressed as Osm/L (pronounced "osmolar"), in the same way that the molarity of a solution is expressed as "M ...
Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes (salts in solution which in this case is represented by body fluid) to keep the body fluids from becoming too diluted or concentrated.
Osm b = Body osmolarity before loss (almost equal to plasma osmolality of 275-299 milli-osmoles per kilogram [4]) TBW b = Total body water before loss (approximately 60% of body weight, or using tritiated water or deuterium) 2. The total amount of substance in the body after the loss is then estimated:
In hypertonic solutions water flows out of the cell and the cell shrinks (plasmolysis). In hypotonic solutions, water flows into the cell and the cell swells ( turgescence ). Osmotic shock or osmotic stress is physiologic dysfunction caused by a sudden change in the solute concentration around a cell , which causes a rapid change in the ...
where is the chemical potential of the pure solvent and is the chemical potential of the solvent in a solution, M A is its molar mass, x A its mole fraction, R the gas constant and T the temperature in Kelvin. [1] The latter osmotic coefficient is sometimes called the rational osmotic coefficient. The values for the two definitions are ...
This is due to urea entering the cell down its concentration gradient, followed by water. The osmolarity of normal saline, 9 grams NaCl dissolved in water to a total volume of one liter, is a close approximation to the osmolarity of NaCl in blood (about 290 mOsm/L). Thus, normal saline is almost isotonic to blood plasma.
In Paramecium, which has one of the most complex contractile vacuoles, the vacuole is surrounded by several canals, which absorb water by osmosis from the cytoplasm. After the canals fill with water, the water is pumped into the vacuole. When the vacuole is full, it expels the water through a pore in the cytoplasm which can be opened and closed ...