Physiology and biochemistry in modern medicine (1918) (14778461501)

Identifier: physiologybioche00macl (find matches)
Title: Physiology and biochemistry in modern medicine
Year: 1918 (1910s)
Authors: Macleod, John James Rickard, 1876-1935 Pearce, R. G. (Roy Gentry), 1884-
Subjects: Physiology Biochemistry
Publisher: St. Louis : Mosby
Contributing Library: Columbia University Libraries
Digitizing Sponsor: Open Knowledge Commons



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Sherrington.) ments, one of which we may cite here. If, in a spinal dog, the tendonsof the flexor muscles of the knee joint of one hind limb and the ex-tensor tendons of the opposite limb are cut, then the former limb willbe unable to flex properly, but will nevertheless exhibit reciprocalinhibition of the intact extensor muscle, while the latter limb will flex,but require passive extension to bring it back to its old position. Ifsuitable stimuli are simultaneously applied to the skin of both legs andthe movements of th,e isolated muscles recorded, the onset of inhibitionof the intact extensor of the one leg and the contraction of the flexorsof the opposite leg will be found to agree with regard to latent periods,strength of required stimulus, summation and indeed all the other phys-iologic properties of reflex action. Reciprocal innervation can also be demonstrated by stimulating thecentral end of suitable afferent nerves—that is, certain afferent nerves RECIPROCAL INNERVATION 817
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Fig. 214.—Reciprocal innervation. Tracings made by myographs connected with E, an ex-tensor muscle (vastus crureus), and F, a flexor muscle (semitendinosus), of a decerebrate cat.At signal / the contralateral peroneal nerve was excited, causing contraction of the flexors and in-hibition of the tone of the extensors. At signal // the flexors were again thrown into contraction byexciting the contralateral peroneal nerve, and (without removing this stimulus) the homolateralperoneal nerve was excited (as shown in the lower signal), with the result that the contractionof the flexors was inhibited at the same time that the extensors contracted. On removal of thelatter stimulus, the former one reasserted its influence. This experiment demonstrates very clearlythe accurate coincidence of the reciprocal action. (From Sherrington.) -)- THE CENTRAL NERVOUS SYSTEM acting on the same groups of neurons will produce a flexion reflex, othersan extension reflex; thus, stimulation of the contralatera