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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.
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 ...
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 ...
These are termed "insensible fluid losses" as they cannot be easily measured. Some sources say insensible losses account for 500 to 650 ml/day (0.5 to 0.6 qt.) of water in adults, [12] [14] while other sources put the minimum value at 800 ml (0.8 qt.). [15] In children, one calculation used for insensible fluid loss is 400 ml/m 2 body surface area.
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.
The process of osmosis over a semipermeable membrane.The blue dots represent particles driving the osmotic gradient. Osmosis (/ ɒ z ˈ m oʊ s ɪ s /, US also / ɒ s-/) [1] is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential ...
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 ...