The involuntary nervous system / by Walter Holbrook Gaskell.

  • W. H. Gaskell
Date:
1920
Catalogue details

Licence: In copyright

Credit: The involuntary nervous system / by Walter Holbrook Gaskell. Source: Wellcome Collection.

    78/200 page 62
    system are found close against the muscles themselves, whether they have travelled out from the bulbar or the sacral regions, whether they are supplying with motor fibres the endodermal muscles in the small or large intestines, in the bladder, in the lungs or in the liver (Fig. 5). Just as the sympathetic vasodermal musculature has invaded the endodermal musculature to form the sphincter of the gut, so also has the endodermal musculature invaded the vasodermal musculature in the case of the heart, as described on p. 80. In the last chapter I pointed out that the sympathetic or vasodermal musculature formed a natural group, because the motor activities of those muscles were alone picked out by adrenalin. Now Dale has found that a substance obtained from ergot, which Ewins working with him has identified as acetyl-choline, when injected intravenously in very minute doses, produces the same effects as stimulation of the bulbo-sacral connector nerves; just as adrenaline injected intravenously in very minute doses produces the same effects as stimulation of the thoracico-lumbar connector nerves. Considering then at present only the motor actions produced by acetyl-choline, we see that it picks out the endodermal musculature just as adrenaline picks out the sym¬ pathetic or vasodermal musculature. I conclude that, in considering the nature of the innervation of involuntary muscle, it is wrong to look upon all unstriped muscle as of the same kind ; the unstriped musculature must be classified into groups, which differ from each other morphologic¬ ally and also in all probability histologically ; thus, as already mentioned, Kalischer looks on the vasodermal musculature as different in structure to the endodermal musculature, judging from the structure of the bladder. Before proceeding to discuss the evidence for a system of inhibitory nerve cells and nerve fibres and glandular nerves, it will be well to sum up the conclusions already arrived at with respect to the purely motor part of the involuntary nervous system. They may be stated broadly as follows :— The motor cells of the involuntary muscles have left the central nervous system to form the various peripheral cell groups, while the motor cells of the voluntary system have remained in the central nervous system ; the axons from these latter form the ordinary motor nerves of striated muscles, the axons from the
    digitised image 1
    digitised image 2
    digitised image 3