A text book of physiology . allel. The katelec-trotonic increase is the first to be developed; it rapidly rises to a maximumand somewhat rapidly declines. The anelectrotonic decrease is not manifestat first; when it does appear it increases slowly, and having reached amaximum diminishes slowly again. When the polarizing current is shut off there is a rebound at bothpoles; a temporary increase of irritability in the anelectrotonic and a tem-porary decrease in the katelectrotonic regions. 74 ELECTROTONUS. [Book i. The amount of increase and decrease is dependent: (1) On thestrength of the curren
A text book of physiology . allel. The katelec-trotonic increase is the first to be developed; it rapidly rises to a maximumand somewhat rapidly declines. The anelectrotonic decrease is not manifestat first; when it does appear it increases slowly, and having reached amaximum diminishes slowly again. When the polarizing current is shut off there is a rebound at bothpoles; a temporary increase of irritability in the anelectrotonic and a tem-porary decrease in the katelectrotonic regions. 74 ELECTROTONUS. [Book i. The amount of increase and decrease is dependent: (1) On thestrength of the current, the stronger current up to a certain limitproducing the greater effect. (2) On the irritability of the nerve, themore irritable, better conditioned nerve being the more affected by acurrent of the same intensity. The increase or decrease of irritability applies not only to theorigination of impulses, but also to their propagation or least anelectrotonus offers an obstacle to the passage of a Fig. 15. Diagram Illustrating the Variations op Irritability during Electro-tonus, with Polarizing Currents of Increasing Intensity (from Pfliiger). The anode is supposed to be placed at A, the kathode at B; AB is consequentlythe intrapolar district. In each of the three curves, the portion of the curve belowthe base line represents diminished irritability, that above, increased represents the effect of a weak current; the indifferent point a\ is near the anode y„, a stronger current, the indifferent point is nearer the kathode B, the diminu-tion of irritability in anelectrotonus and the increase in katelectrotonus being greaterthan in yx; the effect also spreads for a greater distance along the extrapolar regionsin both directions. In y3 the same events are seen to be still more marked. These variations of irritability at the kathode and anode respec-tively must be the result of molecular changes, brought about by theaction of t
Size: 2913px × 858px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, bookpublisherlondo, bookyear1879
