Myotome

“ Thus in large doses it causes a spasmodic and powerful contraction of the muscles of the trunk, and may even produce death by rendering respiration impossible. Its action is propagated from a motor nerve to a muscle, and is kept up for some time. In small doses it is useful in certain cases of paralysis. Two things are necessary in order that it may act efficiently. The muscles of the part must be whole and sound; for if destroyed by excessive atrophy or fatty degeneration, they cannot be roused by any stimulus. ”

“ Given heat and the release of blood pressure, the sudden check of muscular energy consequent upon the wound cuts off from the protoplasm all healthy expenditure of waste, and its action may be brought to a halt so sudden and so effectual as to preclude the slightest change of attitude beyond what may be caused by external forces. Reduced to its plainest terms the idea is as follows: Muscular action and excitement develop heat and chemical action. The myosin, or muscle juice, normally alkaline, is by hard work and excitement rendered acid. ”

“ These units constitute the so-called muscular tissue. Of another tissue—viz., the nervous—the marked features are irritability and automatism, with an almost complete absence of contractility and a great restriction of the other qualities. In a third group of units, the activity of the protoplasm is largely confined to the chemical changes of secretion, contractility and automatism (as manifested by movement) being either absent or existing to a very slight degree. Such a secreting tissue, consisting of epithelium-cells, forms the basis of the mucous membrane of the alimentary canal. ”

“ There can be no doubt that the plasma is the chief seat of differentiation, as Minot has emphasized, and that highly differentiated cells, such as muscle, nerve, and some kinds of connective tissue, have a larger amount of plasma and its products, relative to the nucleus, than have embryonic cells. In the case of fiber cells, fat cells and probably muscle cells, the cell body becomes filled with the products of differentiation and metabolism, which like the yolk in egg cells, or the secretion products in liver cells can not enter the nucleus and consequently do not influence its size. ”

“ It is also necessary, he inferred, for all muscular movements, and he thought there was reason to believe that the sudden contraction of muscle is produced by its combination with other combustible (salino-sulphureous) particles in the body; hence the heart, being a muscle, ceases to beat when respiration is stopped. Animal heat also is due to the union of nitro-aerial particles, breathed in from the air, with the combustible particles in the blood, and is further formed by the combination of these two sets of particles in muscle during violent exertion. ”

“ Our knowledge of the respiratory changes in muscle is more complete than in the case of any other tissue; but we have no reason to suppose the phenomena of muscle are exceptional. On the contrary, all the available evidence goes to show that in all the tissues the oxidation takes place in the tissues and not in the adjoining blood. It is a remarkable fact, that lymph, serous fluid, bile, urine, and the other secretions contain no free or loosely combined oxygen, while the tension of carbonic acid in peritoneal fluid is as high as six per cent, and in bile and urine is still higher, etc. ”

“ In Fig. 12, a branching-out bundle of muscular fibre, taken from the upper lip of the rat, is seen to end in stellate connective cells. The delicate homogeneous sheath that binds the fibres together is termed sarcolemma. This is readily seen in prepared muscle of the frog and water-beetle, less plainly in man. Each muscle is provided with a sheath of connective tissue; this surrounds it, binds the fasciculi together, and supports the blood-vessels; it is called the perimysium, and sends fine prolongations in between the fibres, termed endomysium. ”

“ When, therefore, we wish to relax a muscle that is unnaturally contracted, as by rheumatism or otherwise, we must bring it under the forward end—the outward current—the negative pole. If we desire to contract ligaments or muscles that are abnormally relaxed, (not atrophied) , as in prolapsus uteri, we must subject them to the rear end of the current—the positive pole. Parts that are unnaturally contracted are electrically negative in excess, and need to be made more positive. And parts that are unhealthily relaxed are too positive, and should be made more negative. ”

“ The contact of the muscular fibre with blood-vessels is very close; but the chemical composition of the blood that moistens it varies according to the quantity of work yielded; thus it is indispensable that new fluid should be constantly transfused into the network of veins in the muscle. If the motor fibre is at rest, the blood passing through it is scarcely modified. If it is in a state of half contraction, the oxygen decreases in the blood, and the carbonic acid increases. If contraction is evident and powerful, combustion and production of carbonic acid are then at their maximum ”

“ Mitochondrial transport is reversibly modulated by sequential activation of D2R and D1R receptors As shown in Figures 1 and 2, we found that both D2R and D1R are expressed in the same hippocampal neurons. Since dopamine, which stimulates both D1R and D2R, blocks mitochondrial movement, a D2R-dependent ‘stop’ signal must predominate over a D1R-mediated ‘go’ signal. We wished to determine whether the effect of D2R activation was reversible, and whether inhibited mitochondria could be re-induced to move by subsequent activation of D1R within the same neuron. ”

“ In the Ninth Proposition it is affirmed of Astringent medicines that they act by passing out of the blood to muscular fibre, which by their contact they excite to contraction. They do not so much influence the voluntary fibre of the muscles, which is under the direct control of the nervous system: but they chiefly manifest their action on the involuntary or unstriped muscular fibre, which is not directly controlled by the brain and nerve-centres, and for this reason more under the operation of external or irritating agents. ”

“ Arterial blood passing through the several tissues, becomes once more venous. A considerable quantity of the oxy-hæmoglobin becomes reduced, and a quantity of carbonic acid passes from the tissue into the blood. The blood which comes from a contracting muscle, is not only richer in carbonic acid, but also, though not to a corresponding amount, poorer in oxygen, than the blood which flows from a muscle at rest.
A muscle is always producing carbonic acid, and when it contracts there is a sudden and extensive increase of the normal production. Oxygen is necessary for the life of the muscle. ”

“ In the absence of plain muscular fibres contraction and dilatation of the capillaries can only be effected by a corresponding contraction and expansion of the nuclei of the endothelial cells. As fibrils derived from non-medullated nerves terminate in small end-butts in connection with the capillary membrane, we may assume that the nuclei of the endothelial cells are under the sway of vaso-motor nerve currents, that weak ones will expand, strong ones contract them. ”

“ THE MONOCULAR DUCTION MUSCLE TEST Made with Both Rotary Prisms While the previously described binocular muscle test made with the phorometer and Maddox rod, only determines the existence and amount of esophoria, exophoria, and hyperphoria, neither the faulty nor the deviating muscle is located, hence a monocular muscle test is essential in order to determine whether the muscles of the right or left eye are faulty. Furthermore, an imbalance may possibly be due to either a faulty muscular poise, or lack of nerve force in one or both eyes. ”

“ Based on the analysis of data from time-lapse imaging of cultured hippocampal neurons, we report here that dopamine has a net inhibitory effect on mitochondrial movement. Specifically, whereas activation of the D2 receptor inhibited the movement of mitochondria, activation of the D1 receptor promoted the movement of mitochondria. Consistent with their effects on mitochondrial motility, dopamine agonists and antagonists also showed opposing effects on the Akt-GSK3β signaling cascade, the same pathway that is activated by 5-HT in modulating mitochondrial motility in hippocampal neurons [6] . ”

“ Myxedema subjects show a loss of physical and mental energy which is proportional to the lack of thyroid. Deficiency in any of the organs of the kinetic chain causes alike loss of heat, loss of muscular and emotional action, of mental power, and of the power of combating infections—the negative evidence thus strongly supports the positive. By accumulating all the evidence we believe we are justified in associating the brain, the adrenals, the thyroid, the muscles, and the liver as vital links in the kinetic chain. Other organs play a role undoubtedly, though a minor one. ”

“ These are called muscle cells, and every highly organized animal depends on them for most if not all of the motions which take place in its body. In muscle cells the functional metabolism takes the form of forcible changes in shape of the cells by which bodily motions are brought about. A muscle cell might be described as a mechanical device for transforming the chemical energy of burning fuel into the energy of motion. We have something comparable in the automobile cylinder, where the energy obtained from the explosive burning of the air-gas mixture drives the piston and so propels the car. ”

“ Any one of these kinds of contractility may cease to exist in a muscle and the others may not be affected. Cut its nerves, and there will be no longer any animal contractility; but the two modifications of its organic contractility will continue to subsist. Impregnate the muscle with opium, suffer its vessels to be well penetrated with this substance and it will cease to contract under the impression of stimuli, it will lose its irritability, but it will continue to possess the tonic movements, which are occasioned by the influx of blood into it. ”

“ The diaphragm is a musculo-fibrinous organ and depends for blood and nerve supply above its own location, and that supply must be given freely and pure for nerve and blood or we will have a diseased organ to start with; then we may find a universal atrophy or œdema, which would, besides its own deformity not be able to rise and fall, to assist the lungs to mix air with blood to purify venous blood, as it is carried to the lungs to throw off impurities and take on oxygen previous to returning to the heart, to be sent off as nourishment for the system. ”

“ An animal engaged in battle or in a desperate effort to escape will be able to give a better account of itself if it have some means of accelerating the discharge of energy— some influence like that of pouring oil upon the kindling fire. There is evidence, though perhaps it is not conclusive, that such an influence is exerted by the thyroid gland. In myxedema, a condition characterized by a lack of thyroid secretion, there is dulness of the reflexes and of the intellect, a lowered muscular power, and generally a sluggish discharge of energy. ”

“ From this point of view we must consider substances, which leave the cell and pass into the blood in a state of insufficient decomposition, as being out of harmony with the blood, or rather with the plasma; and, inversely, disturbances would certainly occur in the metabolism of certain cells, if, for instance, the insufficiently decomposed constituents of muscle cells were to penetrate the cells of the kidneys. The units of the muscle cells are out of harmony with the cells of the kidneys, and only a radical reconstruction could make them harmonious therewith. ”

“ If instead of blowing gas into the cellular texture of an animal, we force in different fluid substances, they produce different effects upon the muscles, according to their nature, and to their acrid, soft, or styptic qualities. No injection produces a more sudden and striking effect than that of opium dissolved in water, or than that of its various preparations; when the muscles feel it in contact, their motions cease, they fall as in paralysis. ”

“ What first suggests itself is that the gland cells themselves are made to contract rhythmically by the various conditions which cause rhythmical contractions in muscle. That the stimulus for this must be greater in the case of secretion is shown by the fact that in the intestine peristaltic movements may be maintained in a solution (m/6 NaCl) in which no secretion takes place. It seems not at all improbable that one factor in the production of secretory activity is dependent on a property of the gland cell closely related to muscular contractility. ”

“ Through the nerve cells the heart is affected, and the muscles of respiration are to a similar extent disturbed, and resulting symptoms of self-toxication appear that may end in death. The only means of restoration lies in absolute muscular rest. The heart, though making contractions at the rate of seventy-two beats a minute, is able to continue its work throughout the life of an individual, since each contraction of this muscle is followed by an interval of rest, during which the cells recuperate. ”

“ The food is thus brought into the lymph; and since the lymph lies in actual contact with the living muscle fibres, these fibres are now able to take directly from the lymph the material needed for their use. The power which enables the muscle fibre to take the material it needs, discarding the rest, is, again, one of the vital processes which we defer for a moment.
Respiration.—Pursuing the same line of study, we turn for a moment to the relation of the circulatory system to the function of supplying the body with oxygen gas. Oxygen is absolutely needed to carry on the functions of life ”