Physiological function

“ Human physiology describes the various processes that go on in the human body in health. It treats of the work done by the various parts of the body, and of the results of the harmonious action of the several organs. Broadly speaking, physiology is the science which treats of functions. By the word function is meant the special work which an organ has to do. An organ is a part of the body which does a special work. Thus the eye is the organ of sight, the stomach of digestion, and the lungs of breathing. ”

“ This is plainly self-evident; but when we consider how far-reaching are the facts thus obtained in promoting our understanding of the laws of growth of the human body, of the relationships of the various physiologically active and inactive tissues, of their development, of the character and extent of their activity, and of all the variations incident to pathological conditions, we see at once the great importance of this knowledge in aiding us to a rightful interpretation of physiological laws. ”

“ It is sound physiology, as well as good morals and manners, to cease from the usual routine of six days of mental or physical work, and rest both the mind and the body on the seventh. Those who have succeeded best in what they have undertaken, and who have enjoyed sound health during a long and useful life, have studiously lived up to the mandates of this great physiological law. ”

“ All the experiments in physiology consist practically in the production of so many pathological conditions and states. When the physiologist makes injections, sections and stimulations by various agencies, what else does he effect if not the production of the pathological, in order to learn the physiological action of the various tissues and organs? ”

“ While digestion and absorption of the food are taking place, the nervous system is still in control. The nervous system also regulates pumping of blood over the body, respiration, secretion of glands, and, indeed, every bodily function. Man is the highest of all animals because of the extreme development of the nervous system. Man is the thinking animal, and as such is master of the earth. ”

“ Hence it follows that the sanguineous is the mean system, the centre of organic life, as the brain is of animal life, where those particles to be assimilated, and those, which having already undergone assimilation, are destined to be thrown out, confusedly circulate; so that the blood is composed of two parts, the one recrementitious, produced by the aliments and the exhausted materials of nutrition, and the other excrementitious, which is the rubbage, the residuum of all our organs, and which supplies the secretions and external exhalations. ”

“ 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. ”

“ 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. ”

“ The facts of acclimatization and immunity betray an extraordinary adaptability of the organism to a change in its environment; an organ will adapt itself structurally to an alteration, quantitative or qualitative, of function [Roux’s ‘Functional Adaptation’] ; lost parts can be regenerated; and then there is the physiology of the nervous system. ”

“ In utero the phenomena of the organic life succeed each other with an extreme rapidity; a thousand different motions are incessantly connected in the organs of circulation and nutrition. In these, every thing is energetically in action. But this activity of the organic life supposes a frequent influence exerted upon the brain by [140] the inward organs, and consequently as many reactions on the part of the brain by sympathy upon the muscles. ”

“ Of the five systems, that which has the function of thought and which is the nervous system is ever more and more exercised, until metabolism itself is accelerated to such a degree that the changes in the nervous system are far more rapid than in either of the other four systems. ”

“ 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. ”

“ The assimilation of heterogeneous substances to our organs, is not the effect of any peculiar power. The same may be said of the different principles admitted by a number of authors, who have attributed to results and functions denominations expressive of laws, and vital properties.
The proper life of each organ is composed of the different modifications, to which are submitted in each of them the vital sensibilities and mobilities, modifications, which invariably are productive of others in the circulation and temperature of the organ. ”

“ But if we consider this great function in the important relations of nutrition, secretions, exhalations, for which they furnish the materials, of the general stimulus it carries to all parts, and which is indispensable to the support of life, of the introduction of foreign fluids in the body of the animal, and of the change of these fluids into its own substance ”

“ From a physiological point of view, those metaphysical phenomena of thought, consciousness, and intelligence, which serve for the various manifestations of the human soul, are nothing but ordinary vital phenomena, and can result from nothing but the action of the organ that expresses them. We shall show that, in fact, the physiology of the brain, like that of all the other bodily organs, is deduced from anatomical observations, from experiments conducted physiologically, and from the teachings of pathological anatomy. ”

“ 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. ”

“ 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. ”

“ Simple physiology, as it is usually known, treats of the activities or the functions of the organs, such as the brain, stomach, heart, muscles, spinal cord, lungs, kidneys, etc., which may be considered as carrying on independent processes, or in their vitally coordinated, intimate, mutual relations. But, in contradistinction to this conception of the physiology of organs, there is also a more comprehensive physiology of animal organisms, which may be properly termed universal physiology. ”

“ 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. ”

“ 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? ”

“ For the first time in the history of science, physiologists are now in the position to say that they have arrived at clear and distinct, though by no means complete, conceptions of the manner in which the great functions of assimilation, respiration, secretion, distribution of nutriment, removal of waste products, motion, sensation, and reproduction are performed ”

“ Under the physical theory, as I have elsewhere argued, we should expect to find that organs which are regular in their rhythm of action and are not called upon at intervals to act powerfully would come to be supplied with just enough nutrition to enable them to function properly and would have little capacity to store or to use stored force, and little ability, therefore, to function pleasurably. ”

“ 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. ”

“ But otherwise it may be argued that, since changes of structure and composition, though concomitants of muscular and nervous actions, are not the muscular and nervous actions themselves, the definite excludes the more visible movements with which our idea of life is most associated; and further that, in describing vital changes as a series, it scarcely includes the fact that many of them, as Nutrition, Circulation, Respiration, and Secretion, in their many subdivisions, go on simultaneously. ”

“ 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. ”

“ 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. ”

“ This force is influenced and modified in its action, when exercised in the regulation of nutrition, growth, and reproduction of tissues, by the passions and emotions of the mind. All the secretions and functions of the body are more or less susceptible of being accelerated, retarded or modified by the psychical relations of mind and matter. ”

“ 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. ”

“ We discuss elsewhere the return of vitalism in physiology—that is, the reassertion of a principle of life behind the chemical and physical forces of the human organism regulating it, supplying energy, occasionally enabling it to transcend the ordinary laws of osmosis, or the diffusion of gases. The main seat of this principle of life is in the central nervous system and especially in the cerebral cortex. ”

“ 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. ”

“ The physiological independence of organs, together with their intimate dependence in the organism, and the fact that this organism is incessantly stimulated from many sides at once, assure us a priori that the “waves” of molecular movement due to each stimulus must sometimes interfere and sometimes blend with others, thus diverting or neutralizing the final discharge in the one case, and in the other case swelling the current and increasing the energy of the discharge. We are accustomed to speak of one part “playing on another,” sympathizing with another, and so on ”

“ 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. ”