Carpenter's principles of human physiology . a, the Positive, b, the Negative Pole of a constant current applied to a nerve, a, b, c, a curve,showing the effects of a weak current; d, e, f, of a stronger current; g, k, i, of a very strong portion of the curve below the line shows the degree and extent of the depression, the part aboveof the exaltation of the excitability of the nerve. these, situated at and near the Positive pole, the excitability of the nerve isdiminished, whilst in the other, situated at and near the Negative pole, theexcitability is increased. The extent of the
Carpenter's principles of human physiology . a, the Positive, b, the Negative Pole of a constant current applied to a nerve, a, b, c, a curve,showing the effects of a weak current; d, e, f, of a stronger current; g, k, i, of a very strong portion of the curve below the line shows the degree and extent of the depression, the part aboveof the exaltation of the excitability of the nerve. these, situated at and near the Positive pole, the excitability of the nerve isdiminished, whilst in the other, situated at and near the Negative pole, theexcitability is increased. The extent of the portion of nerve in which the Fig. <v_. n n, represents a nerve; m, a muscle; c c, the positive and negative poles of a constant f, Extra-polar portion of nerve, d, Point to which a stimulus, here represented by b b, the posi-tive and negative poles of an interrupted current, but which may be replaced by a mechanical orchemical excitant, is applied, b, c, indicates the line of normal excitability, supposed for the sake ofsimplicity to be equal throughout the whole length of the nerve, though in reality it is greater, andshould therefore ascend towards b. b, e, g, indicates the curve of augmented excitability in the extra-polar portion of nerve, the amount of increase being greatest at the kathode—as at g, less markedat e, and falling to its ordinary amount at b. excitability is lowered, the positive or anelectrotonic zone, is small in propor-tion to the weakness of the current; whilst the negative or katelectronic zone,in which the excitability is exalted, is correspondingly large ; so that, with verywea
Size: 2284px × 1094px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectphysiology, bookyear1
