ON ELECTRICAL CONDUCTANCE; EEG AND EKG 



221 



average about 0.001 (see Table 8-9) for the ions of tissue fluids. The con- 

 ductance, k, then is easily computed from the above expression, since a « 1 

 for salts in tissue fluids. 



TABLE 8-9. Mobilities* (n) of Selected Ions in Aqueous Solutions at 27° C. 



Blood Plasma Components: 

 Albumins 

 a-globulins 

 /3-globulins 

 Fibrinogen 

 7-globulins 

 Erythrocytes 



5.7 to 6.2 

 3.6 to 5.1 

 2.5 to 3.2 

 1.7to2.3 

 0.8tol.3 

 13 



(buffered 

 at pH 8.6) 



*Dimensions: 



cm / v 

 sec/ cm 



x 10 s . For the small ions, the values refer to infinite dilution. From Ref. 20. 



However, just as diffusion and fluid flow are concentration-dependent, so 

 is electrical conductivity; and it is useful to express conductance per equiv- 

 alent weight. It is called equivalent conductance, A, and is given by 



pV ohm -1 cm -1 



A = t / . m, <x 



equiv// 



This is the most useful way to tabulate conductivity information; and values 

 of A of importance in determining body currents are given in Table 8-10. 



TABLE 8-10. Equivalent Conductances (A) for Selected Salts in Water. 



