Water transport osmotic volume changes

Osmotic Pressure and Cell Volume Changes. Cells shrink when they are exposed to a hypertonic medium or when biochemical processes reduce the number of osmotically active particles. The cell s osmotic balance is restored when inorganic ions such as Na+, K+, and CL enter. In certain cells Na+ and CL may enter in exchange for H+ and I ICO,, respectively. The cell returns to its normal volume as water then flows back into the cell. Cells swell when they are placed in a hypotonic medium or they increase their concentration of osmotically active particles through transport or the degradation of macromolecules. Osmotic balance is restored with the expulsion of inorganic ions, followed by the outflow of water. 

The transport properties that are most significantly affected by changes of the water volume fraction are the water/methanol electro-osmotic drag and permeation, both of which have significant contributions from viscous flow (see Section 3.2.1.1). For DMFC applications (where the membrane is in contact with a liquid water/methanol mixture), this type of transport determines the crossover, which is only acceptably low for solvent volume fractions smaller than 20 vol % (see Figures 14 and 15). Consequently, recent attempts have been focused on strengthening... 

Chloride is mostly described in relation to hydrogen, sodium, potassium, and calcium, except when deviations are well described specifically for Cl in biological systems as a result of deficiency or excess availability. In addition, dysfunctions of CD transport or CD channels are of clinical relevance and have indeed been the subject of intensive research. One principle of CD-mediated effects is a change in osmotic condition, cell volume, and excitability and in acid-base balance in biological systems. In this way, CD is essentially linked to water distribution and electrolyte turnover. 

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