Physiological response

“ So that when we glance at the face we are looking first at the automatically controlled intake openings of the two most important systems in the body, the alimentary and the respiratory, whose muscles contract and relax, ripple in comfort or knot in agony, in response to every important change that takes place throughout the entire extent of both. ”

“ The blood-vascular and respiratory and excretory systems have become well organized, in response, so to speak, to the demands on the part of the nervous and alimentary organs that they may be relieved of the tasks of circulation and respiration and the discharge of ash-wastes. ”

“ Some of its effects are to furnish the blood with chemicals that act as fuel to the muscles, assisting them to contract more vigorously, to make the lungs more active in introducing oxygen into the system, to make the heart more active in distributing the blood throughout the body. Such glandular activity is an important physiological condition of these higher levels of energy. ”

“ And if we ascend to the nervous system, we find how many so-called functional diseases seem to keep themselves going simply because they happen to have once begun; and how the forcible cutting short by medicine of a few attacks is often sufficient to enable the physiological forces to get possession of the field again, and to bring the organs back to functions of health. ”

“ We have thus far considered the normal roles played by the brain, the adrenals the liver, the muscles, and the thyroid in transforming latent into kinetic energy in the form of heat and motion as an adaptive response to environmental stimuli. ”

“ The absence of these essential elements of health deteriorates by materially altering the physical composition of the blood, thus seriously prostrating the vital strength, enfeebling the nervous energy, and ultimately inducing organic changes in the structure of the heart, brain and muscular tissue. ”

“ Modifications in basic behavioral patterns and performance may occur as disruptions of rhythmic physiological phenomena, which are themselves the end product of interrelated functional activity in a number of physiological systems, such as the neuroendocrine, cardiovascular, and central nervous systems. ”

“ Let us here parenthetically notice that the physiological tendency in the nervous system is an evolved complication and a specialized development of one of the fundamental properties of protoplasm—that which is often spoken of as irritability. ”

“ Alterations in those factors which act as vital conditions compose the great mass of physiological stimuli which act continuously on every living organism. The first point to be considered in every alteration is its direction. The alterations produced by stimuli may be of two different kinds, either positive or negative. The quantity of foodstuffs, water or oxygen, in the surrounding medium, can undergo an increase or diminution; as may the temperature, intensity of light, the atmospheric and osmotic pressure. The strength of the electric current, which may be applied, can also be regulated. ”

“ Health consists in normal, functional activity. The human system is the arena of various kinds of motions, both of fluids and of solids, and life and health depend upon these physiological movements. There are the movements incident to respiration, the expansion and contraction of the walls of the chest, bringing the oxygen of the air into contact with the blood as it circulates through the lungs. Corresponding with the movements of the chest are the motions of the abdominal walls, which promote the functions of the organs of the abdominal cavity. ”

“ Every act of volition, every exertion of muscular power, every functional action of the organism, whether perceptible or imperceptible and involuntary, every play of chemical affinity and decomposition, even thought itself, occasions the disorganisation and destruction, as living matter, of a portion of ourselves. But the process of respiration, and the various important changes with which it is connected, tends, more than all the other vital functions, to waste the substance of the body, the temperature of which it is its special office to support. ”

“ The combination of the different varieties of these single factors, that is, the nature, the direction, the intensity, the rapidity, the duration and number of alterations in the external vital conditions of the organism produce the enormous variety of effects of stimulation which we observe in the living world. ”

“ The regulative action of the body upon the soul, although far less uniform, presents a fair analogy. In ordinary health, the measured flow of thought and feeling will bear some relation to the circulation of the blood, the course of respiration, and those general cycles of the body, or human micro-cosmos, which have acquired and preserved a steady rate of movement. ”

“ There are three kinds of stimulus, which may easily be occasionally diminished, that of heat on the skin, of food in the stomach, and of the oxygenous part of the atmosphere, which mixes with the blood in respiration, and stimulates the heart and arteries. ”

“ In all organized living matter, three great fundamental actions are uninterruptedly going forward, namely, capillary circulation, nutrition, and secretion. In man, and in those animals occupying a place near him in the zoological scale, a fourth action, derived from the nervous system, is superadded, which exercises a powerful influence and control over the others. ”

“ This is explained from the physiological point of view by saying that internal and external stimulation—internal from the digestive organs and system in need of food, external through the eye—gives rise to a state of unstable equilibrium in the nerve-centres; and that, when the instability reaches a certain value, the nervous system discharges into the motor organs, the chick pecks, and stable equilibrium is restored. The tendency to discharge in some way under stimulation is an essential characteristic of a nervous system. It is one of the facts of physiological science. ”

“ When these nervous impulses reach the central nervous system in ordinary circumstances they do not give rise to changes that reach the level of consciousness, but they form, as it were, the warp and woof of our mental life, and they also affect metabolisms, that is to say, nutritive changes in many parts of the body. ”

“ Just as the conceptual activity has as its bodily foundation the brain, with the nervous appendages, so it is volitional activity which is based on processes taking place in the muscular region of the body and in those organs which provide the body's metabolism. ”

“ When we come to consider more in detail the results of these actions we find that the various secretions of the body, such as the sweat, gastric juice, bile, milk, urine, &c., may be increased or diminished; that the heart may have its muscular or nervous apparatus stimulated or depressed; that the nerve-centres in the brain, medulla and spinal cord may be rendered more sensitive or the reverse; and that the general metabolism of the body may be altered in various ways. ”

“ The vital powers, and their exciting causes, are continually varying, and thus occasion a constant instability in the functions of the organs, for a thousand causes may at every moment double or triple the activity of the circulation, and respiration, increase or diminish the quantity of bile, urine, or saliva, and suspend or augment the nutrition of the parts. Hunger, food, sleep, motion, rest, and the passions may all of them impress upon these functions so great a mobility, as every day to make them run through a hundred degrees of strength or weakness. ”

“ If it is true that all primary effects of stimulation consist either in an excitation or depression of the metabolism, and that all other effects of stimulation secondarily follow this primary alteration of the metabolism of rest, then every thorough analysis of the mechanics of reaction must have its beginning in the investigation of these primary processes. ”

“ Intercept vital air from the lungs, the action of the heart ceases for want of stimulus, the current of the blood, unaided, yields to the resistance of its channels, all the vital motions are suspended, and the body becomes an inanimated lump of matter. ”

“ We have seen that amongst the phenomena of response, there is no necessity for the assumption of vital force. They are, on the contrary, physico-chemical phenomena, susceptible of a physical inquiry as definite as any other in inorganic regions.
Physiologists have taught us to read in the response-curves a history of the influence of various external agencies and conditions on the phenomenon of life. By these means we are able to trace the gradual diminution of responsiveness by fatigue, by extremes of heat and cold, its exaltation by stimulants, the arrest of the life-process by poison. ”

“ Life is carried on by certain great functions, which we call Respiration, Digestion, Circulation, and Secretion, all of which proceed under the im­pulse of the involuntary nerves; all of them are, however, dependent upon the voluntary nerves and muscles for their proper operation. Breathing requires exercise, change of air and position; diges­tion demands the procuring and preparing of the food; circulation can only be brisk when the body is in motion: and all these motions are necessary to a proper and healthy secretion of the fluids and solids taken into the stomach. ”

“ Don’t you know that physiologists themselves admit that the human body is composed of eighty-five per cent water and fifteen per cent ordinary salts? Can such a combination have intelligence and sensation? Do you still believe that life is dependent upon lungs, stomach, or liver? ”

“ Not only the bodily factors like nutrition and circulation and sexual functions have a thousandfold influence on the psychophysical processes, and these in turn change the vegetative functions of the body, but especially the other parts of the brain and nervous system can be affected in most different ways. ”

“ On the contrary, they include changes and movements in all of the so-called involuntary muscles, and in every kind of bodily structure. They include changes and movements in every part of the physical organism, from changes in the action of heart, lungs, stomach, liver and other viscera, to changes in the secretions of glands and in the caliber of the tiniest blood-vessels. A few instances such as are familiar to the introspective experience of everyone will illustrate the scope of the mind's control over the body. ”

“ All of the vital functions are active; the large chest-room, the vigorous heart, the firm muscles, insure a bodily activity that keeps the operations of organic life in unconscious and easy motion. Digestion, assimilation, excretion, and elimination, work in harmony and with vigor.
Mentally, this type is the reflection of its physical traits. The rich blood, by its active circulation through the brain, causes vivid and active mental action. The general cast of the mind is never gloomy. ”

“ Those that are stimulated are the entire muscular system, the vasomotor and locomotor systems, the senses of perception, the respiration, the mechanism for erecting the hair, the sweat-glands, the thyroid gland, the adrenal gland (Cannon) , and the special senses. On the other hand, all the digestive and procreative functions are inhibited. What is the significance of this stimulation of some and inhibition of other organs? As far as we know, the stimulated organs increase the efficiency of the animal for fight or for flight. ”

“ Let the heart send the blood, thus thoroughly vitalized, bounding and rushing through all parts of the system, even to the ends of the fingers and toes, imparting health, energy, power, spontaneous action, to every muscle, nerve, the brain included. Let the digestion be perfect, Let food never trouble you. Let it fill up your person, make perfect chyle, perfect blood. Let, in short, all the vital organs be fully developed, be healthy, be vigorous, so that your supply of vitality is abundant, and a flow of healthy, happy feeling thrills throughout your whole frame. Disease keeps aloof. ”

“ The nervous system, in its properties and mode of action, is distinct from all the other systems and organs, and it shares with no other organ or tissue the power to do its special work. It is the medium through which all impressions are received. It connects all the parts of the body into an organism in which each acts in harmony with every other part for the good of the whole. It animates and governs all movements, voluntary or involuntary,—secretion, excretion, nutrition; in fact all the processes of organic life are subject to its regulating power. ”

“ PLANT RESPONSE—ON THE RELATION BETWEEN STIMULUS AND RESPONSE Increased response with increasing stimulus —Apparent diminution of response with excessively strong stimulus.
As already said, in the living tissue, molecular disturbance induced by stimulus is accompanied by an electric disturbance, which gradually disappears with the return of the disturbed molecules to their position of equilibrium. ”

“ Since we have spoken of chemical control it will be appropriate to close this chapter with just a further word about it. In addition to the regulation of smooth muscle and gland activity there are a number of other bodily processes which are affected more or less through chemical agents brought to them by the blood. Many of these processes are of a kind that cannot well be controlled through the nervous system. For example, growth is something which goes on very slowly and yet which distinctly requires some kind of control. ”

“ If it is asked, which members of the entire metabolic chain are increased primarily by the stimulating excitation of a vital system, we should not be able to answer this question generally for all living systems. ”