scholarly journals Observations on the theory of respiration

1837 ◽  
Vol 3 ◽  
pp. 334-335
Keyword(s):  
Carbonic Acid ◽  
Venous Blood ◽  
Hydrogen Gas ◽  
The Body ◽  
Pure Hydrogen ◽  
Atmospheric Air ◽  
Acid Gas ◽  
Arterial Blood ◽  
Dark Colour ◽  
Oxygen Gas

From the fact that no carbonic acid gas is given out by venous blood when that fluid is subjected to the action of the air-pump, former experimentalists had inferred that this blood contains no carbonic acid. The author of the present paper contends that this is an erroneous inference; first, by showing that serum, which had been made to absorb a considerable quantity of this gas, does not yield it upon the removal of the atmospheric pressure; and next, by adducing several experiments in proof of the strong attraction exerted on carbonic acid both by hydrogen and by oxygen gases, which were found to absorb it readily through the medium of moistened membrane. By means of a peculiar apparatus, consisting of a double-necked bottle, to which a set of bent tubes were adapted, he ascertained that venous blood, agitated with pure hydrogen gas, and allowed to remain for an hour in contact with it, imparts to that gas a considerable quantity of carbonic acid. The same result had, indeed, been obtained, in a former experiment, by the simple application of heat to venous blood confined under hydrogen gas; but on account of the possible chemical agency of heat, the inference drawn from that experiment is less conclusive than from experiments in which the air-pump alone is employed. The author found that, in like manner, atmospheric air, by remaining, for a sufficient time, in contact with venous blood, on the application of the air-pump, acquires carbonic acid. The hypothesis that the carbon of the blood attracts the oxygen of the air into the fluid, and there combines with it, and that the carbonic acid thus formed is afterwards exhaled, appears to be inconsistent with the fact that all acids, and carbonic acid more especially, impart to the blood a black colour; whereas the immediate effect of exposing venous blood to atmospheric air, or to oxygen gas, is a change of colour from a dark to a bright scarlet, implying its conversion from the venous to the arterial character: hence the author infers that the acid is not formed during the experiment in question, but already exists in the venous blood, and is extracted from it by the atmospheric air. Similar experiments made with oxygen gas, in place of atmospheric air, were attended with the like results, but in a more striking degree and tend therefore to corroborate the views entertained by the author of the theory of respiration. According to these views, it is neither in the lungs, nor generally in the course of the circulation, but only during its passage through the capillary system of vessels, that the blood undergoes the change from arterial to venous; a change consisting in the formation of carbonic acid, by the addition of particles of carbon derived from the solid textures of the body, and which had combined with the oxygen supplied by the arterial blood: and it is by this combination that heat is evolved, as well as a dark colour imparted to the blood. The author ascribes, however, the bright red colour of arterial blood, not to the action of oxygen, which is of itself completely inert as a colouring agent, but to that of the saline ingredients naturally contained in healthy blood. On arriving at the lungs, the first change induced on the blood is effected by the oxygen of the atmospheric air, and consists in the removal of the carbonic acid, which had been the source of the dark colour of the venous blood; and the second consists in the attraction by the blood of a portion of oxygen, which it absorbs from the air, and which takes the place of the carbonic acid. The peculiar texture of the lungs, and the elevation of temperature in warm-blooded animals, concur in promoting the rapid production of these changes.

scholarly journals An account of some experiments on the blood in connexion with the theory of respiration

1843 ◽  
Vol 4 ◽  
pp. 78-79
Keyword(s):  
Carbonic Acid ◽  
Venous Blood ◽  
Pure Oxygen ◽  
Animal Life ◽  
Atmospheric Air ◽  
Acid Gas ◽  
Arterial Blood ◽  
Healthy State ◽  
Oxygen Gas ◽  
Residual Air

The author has investigated, experimentally, several of the important questions connected with the theory of respiration and of animal heat; and arrives at the following results. He finds that the blood is capable of absorbing oxygen both from atmospheric air and from oxygen gas, independently of putrefaction. After blood has been agitated in common air, a trace of carbonic acid not exceeding one per cent., is found in the residual air; but when pure oxygen is employed, no carbonic acid can be detected in it by the most carefully conducted trials. When pure carbonic acid is brought into contact with blood, or serum, over mercury, and moderately agitated, the absorption of gas exceeds the volume of the fluid. Both arterial and venous blood are rendered very dark, and serum more liquid by the absorption of this gas to saturation. Serum, in its healthy state, is incapable of absorbing oxygen, or of immediately furnishing carbon to form carbonic acid: and after it has absorbed carbonic acid, only one-tenth of the absorbed gas is expelled by successive agitation with atmospheric air or with hydrogen. The author is inclined to think that the alkali in the blood, in its healthiest condition, is in the state of a sesquicarbonate. In the majority of trials manifest indications of the disengagement of air from blood in vacuo were obtained: but as it occasionally happened that no air could be thus extricated, the author is induced to believe that the quantity of air contained in the blood is variable: and he has found this air to consist solely of carbonic acid gas. It would also appear, from the experiments detailed in this paper, that a portion of oxygen exists in the blood, not capable of being extracted by the air-pump, yet capable of entering into combination with nitrous gas; and existing in largest proportion in arterial blood. The absorption of oxygen by blood is attended with an increase of temperature. The experiments of the author tend to show that the lungs are absorbing and secreting, and perhaps also inhaling organs, and that their peculiar function is to introduce oxygen into the blood and separate carbonic acid from the blood : and they favour the idea that animal heat is owing, first, to the fixation or condensation of oxygen in the blood in the lungs during its conversion from venous to arterial; and secondly, to the combinations into which it enters in the circulation in connexion with the different secretions and changes essential to animal life.

scholarly journals XXIV. On the respiration of insects

1836 ◽  
Vol 126 ◽  
pp. 529-566 ◽  
Keyword(s):  
Carbonic Acid ◽  
Surrounding Medium ◽  
Relative Volume ◽  
The Body ◽  
Perfect State ◽  
Full Size ◽  
Atmospheric Air ◽  
Acid Gas ◽  
State Of Activity

It has been long proved by many physiologists that insects produce the same changes in the atmosphere during respiration as other animals. Reaumur, Bonnet, Scheele, Huber, Edwards, Audouin, and others, have all shown that the results of the respiration of atmospheric air by insects are the production of carbonic acid gas, and the loss of oxygen; but these results vary in degree in different genera,—in the different states of the same insects, —and at different periods of the year. My object, therefore, in this paper will be to show the relative quantity of air consumed by different tribes of insects in their different states, —the power which particular insects have of supporting existence in different media, -—and the relation which this power and the consumption of air bear to the comparative volume of the structures concerned. The life of an insect has been considered by naturalists to have three distinct periods, the larva, the pupa, and the perfect state; but each of these periods, in so far as the functions of the different structures of the body are concerned, although tending only to the production of the perfect individual, is in itself a distinct condition. Thus the respiration, circulation, temperature, food, and locality of the insect are in general all different in the different states. In the earliest period of the larva state the respiration is much feebler than when the animal has nearly arrived at its full size, and the circulation of its blood is much quicker; but the relative quantity of its food is much greater, in proportion to its bulk, in the latter than at the earlier period, and its power of generating heat increases as it approaches to its adult condition, In the pupa state also there is a change in all these functions. In many genera the insect ceases to eat; its circulation becomes slower than at any other period; its respiration is greatly diminished in frequency and volume; and its power of generating and of maintaining a temperature of body above that of the surrounding medium, which every individual insect constantly preserves when in a state of activity, is now almost suspended. In the perfect, or imago, state there are other changes in these functions. The respiration again increases in frequency and volume; the power of generating and of maintaining heat is very much augmented; the circulation is more rapid than at any other period, while the necessity for a constant supply of food is often less urgent than in the larva state. Hence it is evident that much caution is necessary in drawing conclusions from our observations on the function of respiration in insects in their different states, and that where quantity of air is concerned the relative volume of the organs of respiration must not be forgotten.

Respiratory measurements of cardiac output: from elegant idea to useful test

2004 ◽  
Vol 96 (2) ◽  
pp. 428-437 ◽  
Author(s):  
Gabriel Laszlo
Keyword(s):  
Cardiac Output ◽  
Human Subjects ◽  
Venous Blood ◽  
The Body ◽  
Mixed Venous Blood ◽  
Indirect Determination ◽  
Arterial Blood ◽  
Pulmonary Capillary ◽  
Pulmonary Arterial ◽  
Mixed Venous

The measurement of cardiac output was first proposed by Fick, who published his equation in 1870. Fick's calculation called for the measurement of the contents of oxygen or CO2 in pulmonary arterial and systemic arterial blood. These values could not be determined directly in human subjects until the acceptance of cardiac catheterization as a clinical procedure in 1940. In the meanwhile, several attempts were made to perfect respiratory methods for the indirect determination of blood-gas contents by respiratory techniques that yielded estimates of the mixed venous and pulmonary capillary gas pressures. The immediate uptake of nonresident gases can be used in a similar way to calculate cardiac output, with the added advantage that they are absent from the mixed venous blood. The fact that these procedures are safe and relatively nonintrusive makes them attractive to physiologists, pharmacologists, and sports scientists as well as to clinicians concerned with the physiopathology of the heart and lung. This paper outlines the development of these techniques, with a discussion of some of the ways in which they stimulated research into the transport of gases in the body through the alveolar membrane.

scholarly journals On the respiration of the leaves of plants

1843 ◽  
Vol 4 ◽  
pp. 466-466
Keyword(s):  
Natural Condition ◽  
Carbonic Acid ◽  
Pure Water ◽  
Atmospheric Air ◽  
Acid Gas ◽  
Series Of Experiments ◽  
As If

The author gives an account of a series of experiments on the products of the respiration of plants, and more particularly of the leaves; selecting, with this view, specimens of plants which had been previously habituated to respire constantly under an inclosure of glass; and employing, for that purpose, the apparatus which he had formerly used in experimenting on the combustion of the diamond, and consisting of two mercurial gasometers, with the addition of two hemispheres of glass closely joined together at their bases, so as to form an air-tight globular receptacle for the plant subjected to experiment. The general conclusions he deduces from his numerous experiments conducted during several years, are, first, that in leaves which are in a state of vigorous health, vegetation is always operating to restore the surrounding atmospheric air to its natural condition, by the absorption of carbonic acid and the disengagement of oxygenous gas: that this action is promoted by the influence of light, but that it continues to be exerted, although more slowly, even in the dark. Secondly, that carbonic acid is never disengaged during the healthy condition of the leaf. Thirdly, that the fluid so abundantly exhaled by plants in their vegetation is pure water, and contains no trace of carbonic acid. Fourthly, that the first portions of carbonic acid gas contained in an artificial atmosphere, are taken up with more avidity by plants than the remaining portions; as if their appetite for that pabulum had diminished by satiety.

scholarly journals VI. An examination into the structure of the cells of the human lungs; with a view to ascertain the office they perform in respiration. By Sir Everard Home, Bart. V. P. R. S. Illustrated by microscopical drawings from the pencil of F. Bauer, Esq. F. R. S

1827 ◽  
Vol 117 ◽  
pp. 58-64 ◽  
Keyword(s):  
Carbonic Acid ◽  
Present Theory ◽  
The Other ◽  
Atmospheric Air ◽  
Acid Gas ◽  
Anatomy And Physiology ◽  
Other Hand ◽  
Human Lungs ◽  
Measure For Measure ◽  
Anatomical Knowledge

No subject connected with physiological enquiry has more excited the attention of the anatomist and chemist, than respiration; but the association between this subject and animal heat, which has so long been supposed to exist, has led to the belief, for the last century, that both enquiries belong more particularly to chemistry than anatomy, and I may probably be considered as going out of my province in taking up this investigation. On the other hand, I see reason to believe that the process of respiration is in itself more simple than is imagined, and more within the reach of disco­very by means of accurate anatomical knowledge of the parts employed, than by means of acquaintance with the intricacies belonging to chemical affinities: I carry this so far as to contend that no explanation of respiration upon chemical principles is to be depended on, unless it accord in all respects with the anatomy and physiology of the lungs , by which the assumed process takes place. The present theory respecting respiration adopted by the chemists, is, that this process decarbonises the blood in the following manner; at every inspiration a compound of oxygen and nitrogen, mixed together, is received into the lungs, and in every expiration, the same volume is returned, measure for measure exactly, with this only difference, that what entered as oxygen is returned in the form of carbonic acid gas, which, according to their theory, proves that no part of the inspired atmospheric air has been retained in the lungs, but a quantity of carbon, equal to that of the oxygen inspired, has been extracted from the blood by the oxygen, making it become carbonic acid gas.

scholarly journals Topsy-turvy: turning the counter-current heat exchange of leatherback turtles upside down

2015 ◽  
Vol 11 (10) ◽  
pp. 20150592 ◽  
Author(s):  
John Davenport ◽  
T. Todd Jones ◽  
Thierry M. Work ◽  
George H. Balazs
Keyword(s):  
Heat Exchangers ◽  
Venous Blood ◽  
Vascular Supply ◽  
The Body ◽  
Leatherback Turtles ◽  
The Core ◽  
Arterial Blood ◽  
Hip Muscles ◽  
Counter Current ◽  
Current Heat

Counter-current heat exchangers associated with appendages of endotherms feature bundles of closely applied arteriovenous vessels. The accepted paradigm is that heat from warm arterial blood travelling into the appendage crosses into cool venous blood returning to the body. High core temperature is maintained, but the appendage functions at low temperature. Leatherback turtles have elevated core temperatures in cold seawater and arteriovenous plexuses at the roots of all four limbs. We demonstrate that plexuses of the hindlimbs are situated wholly within the hip musculature, and that, at the distal ends of the plexuses, most blood vessels supply or drain the hip muscles, with little distal vascular supply to, or drainage from the limb blades. Venous blood entering a plexus will therefore be drained from active locomotory muscles that are overlaid by thick blubber when the adults are foraging in cold temperate waters. Plexuses maintain high limb muscle temperature and avoid excessive loss of heat to the core, the reverse of the accepted paradigm. Plexuses protect the core from overheating generated by muscular thermogenesis during nesting.

Water Absorption From the Intestine via Portal and Lymphatic Pathways

1956 ◽  
Vol 184 (3) ◽  
pp. 441-444 ◽  
Author(s):  
John A. Benson ◽  
Philip R. Lee ◽  
John F. Scholer ◽  
Kwang S. Kim ◽  
Jesse L. Bollman
Keyword(s):  
Small Intestine ◽  
Venous Blood ◽  
The Body ◽  
Sodium Ion ◽  
Arterial Circulation ◽  
Intestinal Lymph ◽  
Arterial Blood ◽  
Portal Venous Blood ◽  
Lymphatic Pathway ◽  
Lymphatic Pathways

The content of either D2O or Na24 has been measured in the intestinal lymph, portal venous blood, and femoral arterial blood of unanesthetized hydrated rats after administration of the isotope into the stomach, duodenum, or peripheral or portal vein. Little, if any, water or sodium ion is delivered to the body by a lymphatic pathway after absorption from the small intestine. At least 99% is carried in portal venous blood. The amount of isotope found in intestinal lymph was proportional to lymph volume whatever the route of administration, and derived mainly from the arterial blood. Even during absorption of water or sodium ion from the small intestine the arterial circulation is the principal source of the water and sodium of the lymph.

scholarly journals II. On the properties of matter in the gaseous and liquid states under various conditions of temperature and pressure

1887 ◽  
Vol 178 ◽  
pp. 45-56 ◽  
Keyword(s):  
Carbonic Acid ◽  
Gaseous Mixture ◽  
Acid Gas ◽  
Whole Space ◽  
Intimate Mixture ◽  
Oxygen Gas ◽  
The Moment ◽  
Liquid States ◽  
Elastic Fluids ◽  
Mixed Gases

According to Dalton, the particles of one gas possess no repulsive or attractive power with regard to the particles of another gas; and accordingly, if m measures of a gas A be mixed with n measures of another gas B, each will occupy m + n measures of space. The density of A in such a mixture will be m / m + n' and of B, n / m + n' , the pressure upon any one particle of such a gaseous mixture arising solely from particles of its own kind. “It is scarcely necessary,” Dalton remarks, “to insist upon the application of this hypothesis to the solution of all our difficulties respecting the constitution of mixed gases where no chemical union ensues. The moment we admit it every difficulty vanishes. The atmosphere, or, to speak more properly, the compound of atmospheres, may exist together in the most intimate mixture without any regard to their specific gravities, and without any pressure upon one another. Oxygen gas, azotic gas, hydrogenous gas, carbonic acid gas, aqueous vapour, and probably several other elastic fluids, may exist in company under any pressure, and at any temperature, without any regard to their specific gravities, and without any pressure upon one another, while each of them, however paradoxical it may appear, occupies the whole space allotted to them all.” In conformity with this law, Gay Lussac found that the vapours of alcohol and water mix like two gases which have no action upon one another. The density of the mixed vapours agreed closely with the density calculated according to Dalton’s law. In 1836 Magnus published an important memoir on the same subject. He found that, if two liquids which do not mix with one another are introduced into a barometer tube, the tension of the mixed vapours at any temperature is equal to the sum of the tensions of the vapours of the two liquids. But when the liquids have the property of mixing with one another the behaviour of their vapours he found to be altogether different. The tension of the mixed vapours was no longer equal to the sum of the tensions of each vapour separately. This statement appears at first view to contradict the experiments of Gay Lussac, but, as Magnus himself has pointed out, the conditions under which the observations of the two eminent physicists were made were essentially different. In the experiments of Gay Lussac the mixed liquids were wholly converted into vapour, and therefore the mixed vapours formed were not in contact with any liquid, while in those of Magnus an excess of the mixed liquids was always present, and in contact with the vapour,

Morphometric and flow indicator studies of the teleost heart

1975 ◽  
Vol 53 (6) ◽  
pp. 691-698 ◽  
Author(s):  
James N. Cameron
Keyword(s):  
Body Weight ◽  
Coronary Artery ◽  
Oxygen Uptake ◽  
Blood Supply ◽  
Venous Blood ◽  
Cortical Layer ◽  
The Body ◽  
Unit Weight ◽  
Arterial Blood ◽  
Thymallus Arcticus

The structure of the heart of four species of Alaskan fishes (Thymallus arcticus, Esox lucius, Lota lota, and Catostomus catostomus) was examined in varying detail. The ventricle constitutes 0.07 to 0.09% of the body weight, 26 to 35% of which consists of an outer, cortical layer, and the balance a spongy, trabeculated inner layer. Blood supply to the cortex comes exclusively from the coronary artery, whereas the inner layer is supplied by venous (deoxygenated) blood from the ventricular lumen. Flow indicator studies implied that the cortical layer receives about half as much blood per unit weight as the inner layer, but probably receives about the same amount of oxygen, since arterial blood contains roughly twice as much oxygen as does venous blood. Calculations of the probable limits for oxygen uptake of the ventricle are made on the basis of data in this study and in the literature.

Response to cold of Eskimos of the eastern Canadian Arctic

1963 ◽  
Vol 18 (5) ◽  
pp. 970-974 ◽  
Author(s):  
G. Malcolm Brown ◽  
Robert E. Semple ◽  
C. S. Lennox ◽  
G. S. Bird ◽  
C. W. Baugh
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Canadian Arctic ◽  
The Body ◽  
Arterial Blood ◽  
Acute Cold Exposure ◽  
Body Core ◽  
Average Skin ◽  
Skin Temperatures ◽  
Eastern Canadian Arctic

Skin, muscle, and rectal temperatures, and O2 consumption of Eskimos and Caucasians have been compared during an acute cold exposure involving immersion of one hand and forearm in a 5 C water bath. The Eskimos consumed less O2, maintained their rectal temperatures at a higher level, and gave up less heat from the muscles of the limbs. Though the Eskimos had significantly more adipose tissue, average skin temperatures were the same in the two groups. The pattern of temperatures noted now and the previously observed higher blood flow in the hand and forearm of Eskimos point to increased cooling of arterial blood by returning venous blood in the extremities with resultant preservation of heat in the body core. Submitted on August 6, 1962

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