| Nernst, Walther | <person> German physicist and Nobel laureate, 1864-1941. See: Nernst's equation, Nernst's theory. (05 Mar 2000) |
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| Nernst equation | <physics> A basic equation of biophysics that describes the relationship between the equilibrium potential difference across a semipermeable membrane and the equilibrium distribution of the ionic permeant species. It is described by: E = (RT/zF).ln[C1/C2 Where E is the potential on side 2 relative to side 1 in volts), R is the gas constant (8.314 J Kexp 1 molexp 1), T is the absolute temperature, z is the charge on the permeant ion, f is the Faraday constant (96500 C molexp 1) and C1 and C2 are the concentrations (more correctly activities) of the ions on sides 1 and 2 of the membrane. It can be seen that this equation is a solution of the more general equation of electrochemical potential, for the special case of equilibrium. The equation described the voltage generated by ion selective electrodes, like the laboratory pH electrode and approximates the behaviour of the resting plasma membrane (see resting potential). (13 Nov 1997) |
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| Nernst potential | See: Nernst equation and ion selective electrodes. (18 Nov 1997) |
| Nernst's equation | The equation relating the equilibrium potential of electrodes to ion concentrations; the equation relating the electrical potential and concentration gradient of an ion across a permeable membrane at equilibrium: E = [RT / nF Origin: Ln (C1/C 2)], where E = potential, R = absolute gas constant, T = absolute temperature, n = valence, F = the Faraday, ln = the natural logarithm, and C1 and C2 are the ion concentrations on the two sides; in nonideal solutions, concentration should be replaced by activity. See: Nernst's theory, activity. (05 Mar 2000) |
| Nernst's theory | That the passage of an electric current through the tissues causes a dissociation of the ions, with consequent concentration of salts in the solution bathing the cell membranes, the electric stimulus being thereby effected. (05 Mar 2000) |
| Walther, August | <person> German anatomist, 1688-1746. See: Walther's dilator, Walther's canals, Walther's ducts, Walther's ganglion, Walther's plexus. (05 Mar 2000) |
| Walther's canals | From 8 to 20 small ducts of the sublingual salivary gland that open into the mouth on the surface of the sublingual fold; a few join the submandibular ducts. Synonym: ductus sublinguales minores, Rivinus' ducts, Walther's canals, Walther's ducts. (05 Mar 2000) |
| Walther's dilator | A gently curved instrument that tapers to an increased diameter, used to dilate the female urethra. (05 Mar 2000) |
| Walther's ducts | From 8 to 20 small ducts of the sublingual salivary gland that open into the mouth on the surface of the sublingual fold; a few join the submandibular ducts. Synonym: ductus sublinguales minores, Rivinus' ducts, Walther's canals, Walther's ducts. (05 Mar 2000) |
| Walther's ganglion | The most inferior, unpaired ganglion of the sympathetic trunk; inconstant. Synonym: coccygeal ganglion, Walther's ganglion. (05 Mar 2000) |
| Walther's plexus | <anatomy> The portion of the internal carotid plexus in the cavernous sinus. Synonym: plexus cavernosus, Walther's plexus. (05 Mar 2000) |
| Muller, Walther | <person> 20th century German physicist. See: Geiger-Muller counter, Geiger-Muller tube. (05 Mar 2000) |
| Kruse, Walther | <person> German bacteriologist, 1864-1943. See: Kruse's brush, Shiga-Kruse bacillus. (05 Mar 2000) |
| Flemming, Walther | <person> German anatomist, 1843-1905. See: intermediate body of Flemming, germinal centre of Flemming, Flemming's fixative, Flemming's triple stain. (05 Mar 2000) |
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