On breathlessness, especially in relation to cardiac disease / by Sir Lauder Brunton.

  • Brunton, Thomas Lauder, Sir, 1844-1916.
Date:
1905
Catalogue details

Licence: In copyright

Credit: On breathlessness, especially in relation to cardiac disease / by Sir Lauder Brunton. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    also a regulating power and can replace the action of the vagi when these are divided^ It is probable that both the respiratory stimuli, which act centrally on the nervous system, and those which act peripherally on the lungs and heart, are chemical rather than mechanical, and that they consist of sub- stances whose stimulating action is diminished or destroyed whenever they are fully oxidised. When these substances are produced too quickly or in circumstances which lessen their oxidation, we get hyperpnoea or dyspnoea according to the quantity of the stimulant present. A little extraordinary exertion appears to produce them more quickly than they can be destroyed, so that a person who has run upstairs may palpi- tate and pant for several minutes after the exertion has ceased. When the oxidising power of the blood is diminished, as in anaemia, less exertion is sufficient to produce the panting, and it is apt to last longer after it has been produced. We do not at present know exactly what these stimulating substances are, nor where they are all produced, but many of them are probably produced in the muscles, for Kronecker found that, if one muscle be tetanized, the whole body may be paralysed by its waste products, and Mosso found that the blood of fatigued animals, when injected into healthy animals, caused the heart to beat more quickly and the respiration to become accelerated.^ It is hardly necessary for us to consider the mechanical causes of dyspnoea, such as lessening of the calibre ' Marckwald : Zeitsch. f. Biologic, Bd.XXVL, N.F. VIII., p. 285. Marckwald, using Kronecker's method of rendering various parts of the brain inactive by plugging the arteries supplying them with paraffin injections, came to the follow- ing conclusions:—Neither the cerebrum nor the anterior part of the middle brain has a constant influence over respiration. On the other hand, if the two posterior corpora quadrigemina are paralysed, respiration changes at once, and does not regain its normal character; the long, deep, and quite regular respiratory convulsions occur, which gradually become shorter, and their depth, remaining the same, becomes regular and rhythmic. This alteration of the irregular convulsions is due to the sensory nucleus of the trigeminus. So long as this is active, the respiratory convulsions remain regular; so soon as it is paralysed, they become irregular, their stimuli proceed from the quadrigemina and from the sensory nucleus of the trigeminus which regulates the breathing after the vagi are paralysed. The posterior corpora quadrigemina have a natural tonic action, and can replace that of the vagi when these nerves are cut, while the vagi, on the other hand, can replace the removal of the corpora quadrigemina. After the removal of the posterior corpora quadrigemina the trigeminus nucleus adopts a tonic action. ^ Mosso: Die Ermtidung, Leipzig, 1892, p. 119.