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.

    63/170 page 49
    however, do not quite exhaust the whole story of the heart’s regulation. Yet another phase of heart-control brings us back to our vaso-motor centres and to the control of the blood-vessels. If, from any cause the blood-vessels of the body are in a state of contraction, we may see that the heart will require to exert additional force to propel the blood through them. Now, the heart may be able for a time to supply the increased amount of energy necessary for the efficient discharge of its work; but, as in the case of every other muscle, continued exertion of this nature would certainly cause it to stop work altogether. Nature has therefore pro- vided a most interesting nervous mechanism whereby when the heart is hard-pressed by its work, it cries for and obtains relief. The mechanism in question concerns the action of a certain nerve to which the name of the '' depressor ” is given. Now this nerve carries messages not from brain to heart, but from heart to brain. It is a '' call ” nerve in place of being a “ command ” one. Hard-pressed by its work, a message passes along the de- pressor nerve from the heart to the vaso-motor centre at the top of the spinal cord. We have
    digitised image 1
    digitised image 2
    digitised image 3