Figure 7.
The length constant data obtained for 300, 1000, and 3000 gj-channels are plotted on a semi-logarithmic plot to illustrate that the data points form a straight line. The ordinate gives the ΔVm on a log scale, and the abscissa gives the distance along the cable (one direction only) from the point of current injection (middle of cell 51) and assuming the length of each myocardial cell to be 150 μm. Thus, the second labels on the abscissa give the cell number. The value of the length constant (λ) is the distance at which the voltage falls to 1/e (1/2.717) or 36.8 %. Thus, the following λ values were obtained: 150 μm (for 300 gj-channels), 270 μm (for 1000 gj-channels), and 440 μm (for 3000 gj-channels). Hence, increasing the number of gj-channels 10-fold (300 to 3000) increased λ about 3-fold (150 μm to 440 μm).