On the sources and nature of the powers on which the circulation of the blood depends

1837 ◽  
Vol 3 ◽  
pp. 64-64
Keyword(s):  
Nervous System ◽  
Blood Vessels ◽  
Thoracic Cavity ◽  
Muscular Power ◽  
Voluntary Motion ◽  
Circulation Of The Blood ◽  
Arteries And Veins

In the first part of this paper the author discusses the opinions which ascribe the powers that maintain the circulation in the veins to the elasticity of the heart, the resilience of the lungs, and the dilatation of the thoracic cavity in the act of inspiration. He shows experimentally that the circulation continues unimpaired when all those causes have ceased to operate; and that the very structure of the veins, the coats of which are so pliable as to collapse by their own weight, when empty, renders it impossible that the motion of the blood could be maintained in them by any cause corresponding to a power of suction in the heart. The latter part of the paper is occupied by an inquiry into the sources and nature of the powers which really support the circulation of the blood. The capillaries, he observes, maintain the motion of their blood long after the heart has ceased to beat; this motion not being immediately affected even by the entire removal of the heart; but being accelerated, retarded, or arrested, according as the action of the capillaries is increased, impaired, or destroyed, by agents of which the operation is wholly confined to the vessels themselves. As the destruction of the heart does not immediately influence the motion of the blood in the capillaries, so the action of this organ, when in full vigour, can produce no motion of the blood in the capillaries, when these vessels are themselves deprived of power. Experiments are related with the view of proving that the arteries and veins, and more particularly the latter, are also capable of carrying on the blood they contain, even in opposition to the force of gravitation, with the greatest ease, and without the aid of any extraneous power. With regard to the nature of the power exerted by the blood-vessels, the author shows that the capillaries are as readily influenced by stimulants and by sedatives, as the heart itself; and that the arteries and veins may also be made to obey the action of stimulants ; and further, that the power of the vessels bears the same relation to the nervous system as that of the heart, which is peculiar, and very different from the relation subsisting between that system and the muscles of voluntary motion. From the whole of the facts and experiments stated in this paper, the author deduces the conclusions, that the circulation is maintained by the combined power of the heart and blood-vessels, and that the power of both is a muscular power.

William Harvey and Capillaries

2017 ◽  
Author(s):  
Douglas Allchin
Keyword(s):  
Blood Vessels ◽  
Nature Of Science ◽  
Historical Evidence ◽  
Vital Importance ◽  
Circulation Of The Blood ◽  
Arteries And Veins ◽  
De Motu Cordis

Circulation of the blood is so familiar that one can hardly imagine a time when it was not fully understood. Indeed, the ancients knew about the pulse and the flow of blood. They recognized, too, the vital importance of the heartbeat and nourishment. Yet the concept of a complete blood circuit emerged only in the early 1600s, largely owing to investigations by William Harvey (Figure 23.1). Harvey has since earned renown as one of biology’s great heroes. But what guided Harvey to his landmark discovery? According to many popular accounts, Harvey’s genius was reflected in his remarkable ability to deduce circulation without being able to observe the capillaries that ultimately close the circuit between arteries and veins. Moreover, Harvey’s reasoning was so powerful, they contend, that he was able to confidently predict the presence of the tiny blood vessels without ever seeing them. Only later did others confirm his insightful prediction. That triumph, tragically too late for Harvey himself to appreciate, seems to vividly demonstrate the importance of deduction and prediction in Harvey’s work—and in science generally. However, these stories do not measure up to historical evidence very well. Nonetheless, the widespread error is itself telling. Probing the erroneous stories more deeply, one can gain an even deeper appreciation of scientific myth-conceptions and how they foster misconceptions about the nature of science (essay 21). Most important to understanding Harvey’s discovery, perhaps, is his adoption of the renewed spirit of experimentation in the early 1600s: an eagerness to tinker with and actively probe nature (essay 1). Rather than read books, he dissected animals. He cut open fish, frogs, and other creatures to observe their beating hearts. His unexpected observations led him to new conclusions, which he published in 1628 in De Motu Cordis et Sanguinis, or On the Motion of the Heart and the Blood.

scholarly journals V. On the relation which subsists between the nervous and muscular systems in the more perfect animals, and the nature of the Influence by which it is maintained

1833 ◽  
Vol 123 ◽  
pp. 55-72
Keyword(s):  
Nervous System ◽  
Muscular Power ◽  
Equal Importance ◽  
The Subject ◽  
Circulation Of The Blood ◽  
Complicated Nature ◽  
Made In ◽  
Nervous Influence

In the last paper which I had the honour to present to the Society, and which appeared in the Philosophical Transactions for 1831, I endeavoured, by comparing the various facts relating to the circulation of the blood, and by such additional experiments as seemed to be required, to free the subject from the confusion in which it had been involved by the various and contradictory experiments and statements of writers, and to ascertain the source and nature of the powers on which the motion of the blood depends. In the present paper I propose to consider in the same way, another subject of equal importance, intimately connected with the preceding, and which has, by the same means, been involved in equal, and, from its more complicated nature, apparently greater perplexity; namely, the relation which subsists between the nervous and muscular systems, and consequently, between the nervous system and organs of circulation; for I think it will be admitted, from the statement of facts made in the paper just referred to, that the power of the vessels, like that of the heart, is a muscular power, and that on the combined power of the heart and vessels, the motion of the blood, in the ordinary states of the circulation, wholly depends. Having considered this part of the subject, I shall endeavour to point out how far we can proceed in ascertaining the nature of the nervous influence, the means by which the relation between the nervous and muscular systems is maintained.

Cytochemical Specializations on the Luminal Surface of Blood Vessels in the Developing Rat Central Nervous System

1975 ◽  
Vol 33 ◽  
pp. 462-463
Author(s):  
R. S. Hannah ◽  
T. H. Rosenquist
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Blood Vessels ◽  
Alcian Blue ◽  
Luminal Surface ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Concentration Method ◽  
Endothelial Surface ◽  
Cacodylate Buffer

Developing blood vessels in the rat central nervous system exhibit several unusual luminal features. Hannah (1975) used high voltage electron microscopy to demonstrate numerous ridges of endothelium, some near junctional complexes. The ridges produced troughs (which may appear as depressions) in the endothelial surface. In some areas ridges extended over the troughs, removing them from direct contact with the luminal surface. At no time were the troughs observed to penetrate the basal laminae. Fingerlike projections also extended into the lumina.To determine whether any chemical specializations accompanied the unusual morphological features of the luminal surface, we added 0.1% Alcian blue (Behnke and Zelander, 1970) to the 3% glutaraldehyde perfusate (cacodylate buffer, pH 7.4). After Alcian blue had reacted with the luminal glycocalyces, the dye was dissociated with MgCl2 via critical electrolyte concentration method of Scott and Dorling (1965). When these methods are applied together, it is possible to differentiate mucopolysaccharides (glycosaminoglycans or GAG) with the electron microscope.

Clinical and epidemiological picture of syphilitic infection at present stage

2019 ◽  
Vol 1 (7) ◽  
pp. 42-45
Author(s):  
A. A. Bagirova ◽  
K. M. Lomonosov
Keyword(s):  
Nervous System ◽  
Statistical Analysis ◽  
Blood Vessels ◽  
Case Histories ◽  
Present Stage ◽  
Anatomical Changes

A statistical analysis of the syphilis incidence in Moscow and regions from 2006 to 2017 was carried out. Despite a decrease in the general syphilis incidence an increase in incidence of such severe forms as late neurosyphilis and cardiovascular syphilis was observed. We analyzed 1,600 archive case histories of inpatients and outpatients of the Sechenov University clinics in Moscow and identified the specific lesions in heart tissues, blood vessels and the nervous system. in literal data a relatively small number of cardiosyphilis cases was described. it can be explained by the fact that earlier only gummas, that are rarely to be located in the heart and difficult to be identified clinically, were considered to be the only specific pathological and anatomical changes for syphilis of the heart.

IV. Postscript to a paper “On the ganglia and nerves of the heart.”

1849 ◽  
Vol 139 ◽  
pp. 47-48
Keyword(s):  
Nervous System ◽  
Left Ventricle ◽  
Blood Vessels ◽  
Coronary Arteries ◽  
Royal Society ◽  
Posterior Surface ◽  
Anterior Surface ◽  
Entire Surface ◽  
Naked Eye ◽  
Nervous Structure

Since the communication above referred to was presented to the Royal Society, I have made a very minute dissection in alcohol of the whole nervous system of the young heifer’s heart. The distribution of the ganglia and nerves over the entire surface of the heart, and the relations of these structures to the blood-vessels and muscular substance, are far more fully displayed in these preparations than in any of my former dissections. On the anterior surface, there are distinctly visible to the naked eye ninety ganglia or ganglionic enlargements on the nerves, which pass obliquely across the arteries and the muscular fibres of the ventricles from their base to the apex. These ganglionic enlargements are observed on the nerves, not only where they are crossing the arteries, but where they are ramifying on the muscular substance without the blood-vessels. On the posterior surface, the principal branches of the coronary arteries plunge into the muscular substance of the heart near the base, and many nerves with ganglia accompany them throughout the walls to the lining membrane and columnse carneæ. From the sudden disappearance of the chief branches of the coronary arteries on the posterior surface, the nervous structure distributed over a consider­ able portion of the left ventricle is completely isolated from the blood-vessels, and on these, numerous ganglionic enlargements are likewise observed, but smaller in size than the chains of ganglia formed over the blood-vessels on the anterior surface of the heart. In the accompanying beautiful drawings, Mr. West has depicted with the greatest accuracy and minuteness the whole nervous structures demon­strable in these preparations on the surface of the heart. But the ganglia and nerves represented in these drawings constitute only a small portion of the nervous system of the heart, numerous ganglia being formed in the walls of the heart which no artist can represent. It can be clearly demonstrated that every artery distributed throughout the walls of the Uterus and Heart, and every muscular fasciculus of these organs, is supplied with nerves upon which ganglia are formed.

Some Observations on the Sympathetic Nervous System

1939 ◽  
Vol 85 (358) ◽  
pp. 902-902
Author(s):  
E. Arnold Carmichael
Keyword(s):  
Blood Flow ◽  
Nervous System ◽  
Cerebral Blood Flow ◽  
Sympathetic Nervous System ◽  
Arterial Pressure ◽  
Blood Vessels ◽  
Fluid Pressure ◽  
Spinal Fluid ◽  
Cerebral Blood Vessels ◽  
Sympathetic Nervous

Outline of physiology of sympathetic nervous system and its effect on the cerebral blood-vessels. Other factors controlling cerebral blood-vessels, such as local intra-arterial pressure and gas tension. The action of adrenalin-like and cholin-like substances on the cerebral blood-vessels. Alteration in cerebral blood flow during a convulsion, and the accompanying changes in cerebro-spinal fluid pressure. Evidence for systemic sympathetic disturbance during a convulsion. Discussion of “vaso-vagal” attacks and “diencephalitic” epilepsy.

scholarly journals VIII. On the structure, relations, and development of the nervous and circulatory systems, and on the existence of a complete circulation of the blood in vessels, in myriapoda and macrourous arachnida.—First series

1843 ◽  
Vol 133 ◽  
pp. 243-302 ◽  
Keyword(s):  
Nervous System ◽  
Royal Society ◽  
Complete System ◽  
Comparative Anatomy ◽  
The Body ◽  
Circulation Of The Blood

The increasing importance that is daily attached to the study of the comparative anatomy of the Invertebrata, and the interest with which every microscopic exami­nation of structure is now regarded, as assisting to elucidate the great problems of life in the higher animals, have encouraged me through several years to prosecute a series of investigations, in the articulated classes, on two of the most important portions of the body,—the nervous and circulatory systems. These investigations have afforded me, from time to time, some interesting results, part of which, on one of these structures, I have already had the honour of communicating to the Royal Society. I now propose to communicate the results of my examinations of both these structures, and to illustrate their development, and the relations which they bear to each other, in some of the principal classes, commencing, in the present paper, with the Myriapoda and Arachnida. The objects to which my attention has been directed in this paper are three:— First , the minute anatomy of the nervous system in the Myriapoda and Macrourous Arachnida, more especially with regard to the structure of the cord and its ganglia, and the means which these afford us of explaining the physiology of the nervous system, and the phenomena of the reflected movements in articulated animals. Secondly , to demonstrate the existence of a complete system of circulatory vessels in the Myriapoda and Arachnida. Thirdly , to show the identity of the laws that regulate the development of the nervous and circulatory systems in these Articulata, and their dependence on the changes which take place in the muscular and tegu­mentary structures of the body, as I formerly showed in regard to the changes in the nervous system of insects.

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