Our brain, body and nerves / by Andrew Wilson.

  • Wilson, Andrew
Date:
1911
Catalogue details

Licence: In copyright

Credit: Our brain, body and nerves / by Andrew Wilson. Source: Wellcome Collection.

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    seen that it is this centre which has charge of the blood - vessels. Accordingly, when the heart’s call reaches this centre, we find that sub-office at once exerting a restraining in- fluence, such as we saw to be produced in the act of blushing. The blood-vessels of the body, and especially those near the heart, are made to expand, so the flow of blood along them from the heart, and indeed all through the body, becomes easier. The blood pressure is lessened, so to speak, and the heart is relieved of the tension which it required to exert in its work of driving blood through narrow channels. The influences which the nerve centres and nerves of the heart exert in producing emo- tional displays need not be specially dwelt upon. The faster beating of the heart is due, as we may see, to the brain’s action on the sympathetic nerve-trunks, just as the re- straint of the organ is caused by some influence affecting the vagus nerve. A blow on the stomach or chest may cause a man to faint, because the reflex has passed from the nerves of the affected part to the brain, and has thence been reflected to the vagus nerve, producing temporary stoppage or delay of
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