The effect of progesterone on the human uterus.

responding patch.In the absence of propagation, action potentials of perfectly graded height can be produced (ref.3).It will be noted in ref. if, Fig. 2, that in the presence of the 4-megohm shunt across the second gap, action potentials appearing after long utilization time were no longer elicited and that the brief action potentials were followed by the R. deflection until the applied current became large enough to reduce the effectiveness of the RI process.The transition from record 11 to record 12 (if, Fig. 2) was all-or-nothing.However, as will be illustrated in a future communication, in the presence of a low-resistance shunt across the second gap the height of the action potential may be perfectly graded from zero up to maximal.3(a) Honrubia, V., and R. Lorente de N6, these PROCEEDINGS, 48, 2065 (1962); (b) ibid., 49, 40 (1963).The texts of these communications remain fully valid if the term "node" is replaced by "responding paranodal segment," because under the experimental conditions that were used, either only one paranodal segment is able to produce an action potential or if both paranodal segments respond to the stimulating current, they do so almost simultaneously.