Electrolytes have four main functions:
- Establish the osmotic concentration gradients on cell
membranes
- With balanced concentrations together with acid-base buffers
establish the optimal acidity.
- With balanced concentrations together with radicals and
antioxidants establish the optimal reduction potential.
- Electric signaling of cells such as neural action potential is
possible because of passive/active selective membrane transports of
electrolytes.
The main electrolytes are:
- Sodium (Na+). Reabsorption of sodium in kidney nephrons is one
of the main power for reabsorption of water [Wright1982,Bruun1990].
This process is driven by aldosterone[Young1976,Stanton1986] and
angiotensin II [Ofangii1986,Lohmeier1998,Seeliger1999]. Sodium is
reabsorbed in each part of nephron in different way such as from
proximal tubule [Wiederholt1967,Gullans1985], from loop of Henle
[Cortney1966] or from distal tubule[Morgan1969]. Other type of
excretion is by sweating[Epstein1999,Quinton1991,Sato1989].
- Potassuim (K+). The main compartment for potassium is
intracellular fluid. Excretion of potassium by nephrons is driven
also by aldosterone feedback control [Young1976, Young1983,
Young1988]. The amount of secreted potassium to urine is dependent
also on potasium plasma concentration [Toussaint1962] and on sodium
excretion [Good1984,Young1984]. Other type of excretion is by
sweating[Epstein1999,Quinton1991,Sato1989].
- Chloride(Cl-) is the main plasma anion. His renal excretion
such as renal excretion of amonium and bicarbonates is driven by
the acidity of plasma [Cogan1979,Sartorius1949]. Other type of
excretion is by sweating[Epstein1999,Quinton1991,Sato1989].
- Amonium(NH4+) is formed and excreted in kidney to compensate
plasma hydrogen ions concentration[Rodriguez-Nichols1984], because
its production consume the free hydrogen ions changing to a strong
cation at pH<=7.4.
- Phosphates(H2PO4-, HPO4^2-) and sulphate(SO4^2-) has no renal
reabsorption, which means, that their excretion to urine is
dependent only on Donnan's equilibrium on glomerular membrane
[Donnan1911].
Contents
Author:
|
Marek Matejak
|
License:
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Physiomodel
License 1.0
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Date of:
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2008-2015
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References:
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Tom Coleman: HumMod 1.6, University of Mississippi Medical
Center
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Copyright © 2008-2015 Marek Matejak, Charles University in
Prague.
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