Nerves / by David Fraser Harris.

  • David Fraser Fraser-Harris
Date:
[1913]
Catalogue details

Licence: Public Domain Mark

Credit: Nerves / by David Fraser Harris. Source: Wellcome Collection.

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    which are stimulated only in abnormal and painful conditions. Then, more vague still, are such sensations as hunger, thirst, the feeling of being well, the feeling of being ill (malaise), which certainly are related to states of tissues, for it is tissue-nutrition that determines hunger, thirst, and the like. Summarising the sources of afferent im¬ pulses as regards their sites of origin we may say they are of three kinds, namely—• First, those receiving stimulation from external sources, or the extero-ceptive ; Secondly, those receiving stimulation from internal organs, or the entero-ceptive ; and Thirdly, those receiving stimulation from the states of the tissues themselves, the proprio-ceptive. The extero-ceptive are also called distance- receptors, since they have to do with sensa¬ tions aroused by forms of energy present in the outer world, and it may be coming from sources very far away : the entero-ceptive and proprio-ceptive inform us about changes in our own bodies. All these receptors are transformers of energy; the extero-ceptive transform light, sound, chemical activity, into nerve-impulses ; the entero-ceptive trans¬ form, for the most part, internal pressures
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