Sympathetic nervous system

“ These last are structures in which one neurone makes communication with other neurones. To that extent, therefore, redistribution of nervous impulses does occur in them, impulses arriving by a few neurones being distributed so as to affect many. But the sympathetic ganglia are not the seat of reflex action. The sympathetic system is now known to consist entirely of conducting paths which, like the nerve-trunks of the cerebro-spinal system, merely conduct nerve impulses either toward the great nervous centres of the spinal cord and brain, or, on the other hand, away from those great centres. ”

“ The pathology of these disorders would be more fully understood were our knowledge of the physiology of the heart's movements more complete. We know that contractions of the heart continue when it is separated from all its nervous connections and after removal from the body, especially in cold-blooded animals. The rhythm, frequency, and force of its normal movements are evidently dependent on influences derived through the sympathetic and pneumogastric nerves. ”

“ There are, for these two systems of organs, two nervous systems, in great measure independent; and, if it is true that the higher system influences the lower, it is no less true that the lower very powerfully influences the higher. The restrictive action of the sympathetic upon the circulation, throughout the nervo-muscular system, is unquestionable ”

“ It will be seen that lesions which affect not only nutrition of parts, but also the higher functions of the nervous system, can be developed by hereditary tendencies, when artificially provoked, through those nerves which minister to organic functions—belonging to the so-called sympathetic system. ”

“ The chief interest of the hypothesis of structural continuity through the protopathic nervous system, with its corollary of sympathetic nutritional change, lies in the explanation which it affords of the influence upon reflex action of the establishment of a pain-condition in the axial nervous system in circumstances in which, consciousness not being affected, there is no "pain." ”

“ An example of such a secondary affection is the combination of sympathetic symptoms occurring in progressive muscular atrophy. And, finally, since mental action of an emotional nature may cause flushing or pallor of the face, with profuse sweating and variations in the size of the pupil and prominence of the eyeballs, as well as palpitation or arrest of the heart, there is reason to believe that symptoms of sympathetic disease may be produced by cerebral lesions. ”

“ When we remember that this nerve is both sensory and motor in function, and that the inhibitory influence to which the heart's action is subject is accomplished through the sympathetic as a sensory nerve and the pneumogastric as a motor, there is no reason why similar results may not be brought about by the sympathetic alone. ”

“ Thus when there is a local injury, the whole frame after a time suffers with it. A wound anywhere will tend to create feverishness everywhere; derangement of the stomach will tend to produce headache, liver complaint to produce pain in the shoulder, etc.”
An old authority thus describes the Sympathetic Nerves: “A system of nerves, running from the base of the skull to the coccyx, along both sides of the body, and consisting of a series of ganglia along the spinal column by the side of the vertebræ. ”

“ After long and conscientious researches, M. Chossat concluded that the sympathetic nerve is the real heat-producing agent in animals. But if, after having cut the brain transversely in front of the pons varolis, after having suppressed all nervous action by a cerebral shock violent enough to cause death, after having cut both the pneumo-gastric nerves, after having made various sections of the spinal cord, after having dissected out the sympathetic nerve above the solary plexus, after having practised ligature of the aorta below the diaphragm ”

“ Every portion of the body has nerves of sensation coming from the spine, and also branches of the sympathetic or ganglionic system. The object of this is to form a sympathetic communication between the several parts of the body, and also to enable the mind to receive, through the brain, some general knowledge of the state of the whole system. It is owing to this that, when one portion of the body is affected, other portions sympathize. For example, if one part of the body is diseased, the stomach may so sympathize as to lose all appetite until the disease is removed. ”

“ General sensibility, whether of the internal or external organs of the body, chiefly depends upon the sensory fibres of the spinal nerve. The face, however, is supplied by the sensory cranial nerves. The sympathetic system has a low grade of feeling in health; but disease in the parts served by it arouses an intense degree of pain. ”

“ The heart, then, during the act of smoking, was doing extra work; in some of the experiments this additional labor amounting to more than 50 per cent.
The effect upon the heart is not caused by direct action upon that organ, but by paralyzing the minute vessels which form the batteries of the nervous system. Thus paralyzed, they can no longer offer effectual resistance, and the heart, freed from their control, increases the rapidity of its strokes, expanding the vessels, with an apparent accession, but real waste of force. ”

“ Thus it happens that for the most part only conjectures, often very insecurely based are current, or can be said to exist in regard to the dependence of definite sets of symptoms, or distinct diseases, upon disordered actions or morbid changes occurring in one or other part of the sympathetic system of nerves. ”

“ Observe that organic sensibility and contractility are almost always in action in cellular sympathies, because these are the two vital forces essentially predominant in that system. Thus sensible organic contractility and animal contractility are particularly exercised in muscular sympathies, according as the system of organic muscles, or that of the muscles of animal life, receive sympathetic excitement. ”

“ The centre of the cardiac nerves is in the medulla oblongata, in the most important part of the nervous system, near that point the wounding of which even with a pin-point causes instant death, because there all the paths of the nervous system converge. ”

“ Usually, these symptoms are accompanied by disturbances of some other of the organs under the influence of the pneumogastric and sympathetic nerves. The heart is agitated by violent palpitations, a cold sweat breaks out, and a vertigo may accompany it, which, but for the fact that it is not relieved by the vomiting and from its other associations, might mislead the physician into regarding it as a reflex symptom. In other cases the symptoms of disturbed cardiac innervation or those of respiration are in the foreground, constituting respectively the cardiac and bronchial crises. ”

“ They have no direct action on the heart, and only affect that organ secondarily through the medium of the lungs. Their action on the nervous system consists in firstly irritating and secondly paralyzing the peripheral sensory nerves and posterior roots of the spinal nerves. ”

“ The second, the sympathetic nerve system, consists of all the nerves of the unconscious or functional life; it therefore includes all nerves running between the brain and sympathetic or involuntary nerve centers on the one hand and the involuntary muscles on the other. ”