The common variety of bed-sore is the result of continuous pressure on and irritation of the skin, the vitality and resisting power of which are lowered by a lesion of the cord cutting off the trophic supply to the skin affected.
It is much more likely, as Verworn alleges, that the nerves which influence the characteristic function of any tissue regulate thereby the metabolism of the cells in question - in other words, that every nerve serves as a trophic nerve for the tissues it supplies.
The earliest interpretation put upon this experiment was that the trophic influence of the nerve having been withdrawn, the tissue failed to nourish itself, and that degeneration ensued as a consequence.
In addition to the trophic influence exerted by each part of the neuron on its other parts, notably by the perikaryon on the cell branches, one neuron also in many instances influences the nutrition of other neurons.
In the Telosporidia (comprising the Gregarines, Coccidia and Haemosporidia), sporulation does not begin until the close of the vegetative or trophic period, i.e.
This trophic influence which one neuron exerts upon others, or upon the cells of an extrinsic tissue, such as muscle, is exerted in that direction which is the one normally taken by the natural nerve impulses.
The acute bed-sore is, in some cases, a true trophic lesion occurring, as it may, on parts not subjected to continuous pressure or irritation.
In diameter, with little yolk, and the embryos provided with large trophic vesicles (Willey).
If, on the other hand, any pathogenic organisms be present the results are disastrous because the tissue, deprived of its nervous trophic supply, has greatly lessened resistance.
A Trypanosome always possesses two distinct nuclear bodies, one the trophonucleus, regulating the trophic life of the cell, the other, the kinetonucleus, directing its locomotor activities.