Circulation (physiology)

“ No other single discovery with reference to the human body has proved of such great importance. A knowledge of the nature and purpose of the circulation was the necessary first step in understanding the plan of the body and the method of maintaining life, and physiology as a science dates from the time of Harvey's discovery.
Organs of Circulation.—The organs of circulation, or blood vessels, are of four kinds, named the heart, the arteries, the capillaries, and the veins. ”

“ Observe also, that united with the weakness of the motion that animates the blood, it is a cause of the small degree of excitement which the parts have in old age. In fact the use of the circulation is not only to carry to the different parts the materials of the secretions, of exhalations, nutrition, &c. ”

“ It has been stated that the circulation languishes with the diminished energy in the sensorial faculties, and the loss of power in the muscles of locomotion. After awhile, the pulse which was feebler than natural becomes more full, more strong, and generally more quick than in a sound state ”

“ In perfectly normal action it is likely that the molecular changes are the dominant factor and keep the circulation under control; but not unfrequently the mass and velocity of the circulating fluid may determine the sphere as well as the character of the activity, and thus have effect on the outcome, whether muscular or mental. ”

“ Hence if the sensorial power be lessened, while the quantity of stimulus remains the same as in nervous fever, the frequency of repetition of the arterial contractions may continue, but their force in respect to removing obstacles, as in promoting the circulation of the blood, or the velocity of each contraction, will be diminished, that is, the animal strength will be lessened. ”

“ They steady the circulation, the heart action, muscles and nerves of the mind. If the heart flutters, the circulation is not regular, and when the lung action is uneven, the mind becomes unsteady and not fit for concentration. ”

“ Let it be noticed however, that each organ independently of the general sensibility, mobility, temperature, and circulation of the body, has a particular mode of sensation and heat, together with a capillary circulation, which being withdrawn from the influence of the heart, receives the influence only of the tonic action of the part. ”

“ He may be intensely excited, but the natural muscular response does not follow. His heart is accelerated and his blood pressure raised, but neither muscular movements and accompanying changes of posture, nor the respiratory pump materially aid the circulation. The activity of his brain demands a rapid flow of blood, and his heart has to do the circulatory work, as he sits still or stands at his desk, against the influence of gravity. ”

“ This circulation goes on from year to year as regularly as that of the blood, in the veins and arteries of the human system, and though maintained by a very different machinery, is no less clearly adapted to its purposes. ”

“ A circulation, which is but a repetition of rhythmical motion, once set up, organization is complete. Endow this organization with continuity, or the power of repeating itself, which the rhythmical circulation and polarity are capable of doing; endow it with the power of inspiring other colloid and crystalloid atoms with like vibrations, attracting them into its own mass, and then ejecting them again, arranged in form like to the original cell, which it will continue to do from habit, and you have living creatures. ”

“ Second step—Heat evolved in the lungs by Respiration there produces Expansion. Third step—Expansion; implied motion, which from the organism must conduct the blood to the left ventricle of the Heart. Theory imperfect, until the formation of sufficient vapor or steam in the lungs is perceived and acknowledged. ”

“ While the heart is thus laboring under the action of alcoholic stimulation, a change is observable in the extreme circulation—that circulation of blood which by varying shades of color in exposed parts of the body, such as the cheek, is visible to the eye. The peripheral circulation is quickened, the vessels distended. ”

“ 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 residual air in a lung is the basis of the respiratory process; the sustained tension of the smaller arteries transforms the pulsating current of blood thrown into the system by the heart to a continuous circulation; the equilibriated tonicity of opposing muscles gives stability to the apparatus of motion, and renders specific combinations of movement possible. ”

“ When two events are so conjoined in nature that one is the only invariable antecedent of the other, then, according to all logic, we are bound to conclude that the first is the physical cause of the second, even though we cannot understand how it should be. Of the circulation, such living respiration as produces heat is the invariable antecedent, and nothing else is. The heart’s action, as stated by our reviewer himself, is not therefore respiration, and not the heart’s action or anything else, is the cause of the circulation. ”

“ It is certain nothing is so likely, by accelerating the contained fluids, to dilate and open the passages, as well as divide the coagulated particles of blood, that so the circulation may be again performed. ”

“ When, for instance, there is a great expenditure of motion through muscular activity, there arises a re-active demand on those stores of latent motion which are laid up in the form of consumable matter throughout the tissues: increased respiration and increased rapidity of circulation, are instrumental to an extra genesis of force, that counter-balances the extra dissipation of force. This unusual transformation of molecular motion into sensible motion, is presently followed by an unusual absorption of food—the source of molecular motion ”

“ In the phenomena of general circulation the blood may be said to do nothing more than traverse the parts, to pass from the arteries into the veins; in the phenomena of local, which is the true functional circulation, the blood penetrates all the folds of the organ, and gathers closely about its anatomical elements, to arouse and excite their special mode of activity. The nervous system, sensitive in its action through the vessels, governs all those phenomena of local circulation which attend organic activity ”

“ And it was in performing this experiment that a truth was discovered, which, had it been known, many who have ignorantly lost their lives might have preserved them. When the fluid in the apparatus became equally, or nearly as much, heated at the extreme parts of the circulating tube as at the heating vessel, then the motive power of expansion ceased, and (the hand’s impulse being too weak of itself to carry it on) circulation failed ”

“ My next postulate is, that the activity of the brain is conditioned by the activity of its circulation. The blood is to the gray matter of the convolutions what atmospheric air is to burning fuel; it is at once a necessity and a stimulus. However favorable may be the arrangement of cell and fiber, the consciousness will fail to respond to any impression, and every cerebral function will be impaired or suspended, if the circulation be lowered below a certain amount. ”

“ The blood vessels are elastic, and the study of the effect of a liquid pumped rhythmically into elastic tubes explains with simplicity the various phenomena associated with the circulation. For example, the rhythmically contracting heart forces a small quantity of blood into the arteries at short intervals. ”

“ Indeed, I have very often found that even when the leaping point lies still and devoid of all motion as though quite dead, it recovers motion and pulsation again if warmed afresh. From the foregoing I judge that in the order of generation the point and the blood come into existence first ”

“ It has been ascertained that compared with the velocity of light and electricity, the velocity of thought is astonishingly small. If I touch the skin of an adult’s leg, it takes no less than about one third of a second before the sensation is reported by the spinal cord to the brain,—the central organ of consciousness; whereas in the same time light will travel over more than fourteen thousand geographical miles; electricity, conducted by a copper wire, nearly thirty-one thousand miles. ”

“ Habitual motion is necessary to all the parts of the body alike, is a condition essential to the functions of the muscles, the glands, the vessels, and the membranes, &c. But this movement, which is partly derived from the [196] heart, is very different from that which is communicated by the blood to the brain. ”

“ The blood, therefore, required to have motion, and indeed such a motion that it should return again to the heart; for sent to the external parts of the body far from its fountain, as Aristotle says, and without motion, it would become congealed. For we see motion generating and keeping up heat and spirits under all circumstances, and rest allowing them to escape and be dissipated. ”

“ We may say, speaking somewhat roughly, that a stimulus applied to the nervous system, like a spark to dynamite, is able to take advantage of the stored energy in unstable equilibrium, and thus to produce movements out of proportion to the proximate cause. Movements produced in this way are vital movements, while mechanical movements are those in which the stored energy of a living body is not involved. ”

“ The circulation remains efficient not only in the horizontal but also in the erect position, and just as much so when a man, like a gymnast, is ceaselessly shifting the position of his body. Yet in a man standing six feet the hydrostatic pressure of a column of blood reaching from the vertex to the soles of the feet is equal to 14 cm. of mercury. The blood, owingInfluence of posture on the circulation. to its weight, continually presses downwards, and under the influence of gravity would sink if the veins and capillaries of the lower parts were sufficiently extensile to contain it. ”

“ Nor is it to be expected that because of the motion of the blood, the time at which the contraction of the heart takes place, and that at which the pulse in an artery (especially a distant one) is felt, shall be otherwise than simultaneous: it is here the same as in blowing up a glove or bladder; for in a plenum (as in a drum, a long piece of timber, etc.) the stroke and the motion occur at both extremities at the same time. ”

“ The greater the action of the stimulus of the blood, the greater will be the contraction, that is, the nearer will the sides of the artery approach towards the axis. 3d. That the velocity with which a muscular fibre, in a state of debility, contracts, is at least equal to that with which a fibre in a state of strength contracts, is a fact generally allowed by physiologists. ”

“ The motion of the heart, then, is entirely of this description, and the one action of the heart is the transmission of the blood and its distribution, by means of the arteries, to the very extremities of the body; so that the pulse which we feel in the arteries is nothing more than the impulse of the blood derived from the heart. ”

“ Finally, that the pulses of the arteries are due to the impulses of the blood from the left ventricle, may be illustrated by blowing into a glove, when the whole of the fingers will be found to become distended at one and the same time, and in their tension to bear some resemblance to the pulse. For in the ratio of the tension is the pulse of the heart, fuller, stronger, more frequent as that acts more vigorously, still preserving the rhythm and volume, and order of the heart's contractions. ”

“ In a word, each excitation, according to its energy, produces more or less extensive movement which may be limited to a single group of muscles. It is not so with a frog in which the spinal cord is unsevered; the movements which succeed a stimulus, whether it be strong or feeble, are always movements of the whole body. ”

“ A somewhat higher level on the inclined plane is illustrated by what are called "tropisms," obligatory movements which the animal makes, adjusting its whole body so that physiological equilibrium results in relation to gravity, pressure, currents, moisture, heat, light, electricity, and surfaces of contact. A moth is flying past a candle; the eye next the light is more illumined than the other; a physiological inequilibrium results, affecting nerve-cells and muscle-cells ”

“ The Pulse.—With each contraction of the left heart, the impulse causes a wave-like motion to traverse the entire arterial system. If the arteries were exposed to view, we might see successive undulations speeding from the heart to the smallest of the branches, in about one-sixth part of a second. ”

“ The motions of our own bodies are attended by the vibrations peculiar to pressure, and muscular contraction; of other bodies which touch our own, by those from pressure. We judge of rest by the absence of these. Distance is judged of by the quantity of motion, and figure by the relative quantity of distance. And thus it appears, that all degrees and kinds of these tangible qualities may impress corresponding vibrations upon those regions of white medullary substance of the brain, and spinal marrow, which correspond to the skin and muscles. ”

“ The sensorial power, or spirit of animation, used in giving perpetual and strong motion to the heart, which overcomes the elasticity and vis inertiæ of the whole arterial system; next the expense of sensorial power in moving with great force and velocity the innumerable trunks and ramifications of the arterial system; the expense of sensorial power in circulating the whole mass of blood through the long and intricate intortions of the very fine vessels, which compose the glands and capillaries ”