Dynamics of the Molluscan Circulatory System: Open versus Closed

1990 ◽  
Vol 63 (1) ◽  
pp. 140-166 ◽  
Author(s):  
G. B. Bourne ◽  
J. R. Redmond ◽  
D. D. Jorgensen
2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Carl L. Reiber ◽  
Iain J. McGaw

Invertebrate cardiovascular systems have historically been viewed as sluggish, poorly regulated, and “open”, where blood bathes the tissues directly as it moves through a system of ill-defined sinuses and/or lacunae without an endothelial boundary. When examining cardiovascular/circulatory morphology and physiology in a broader evolutionary context, one can question the very nature of the definition of a “closed” versus “open” circulatory system. Viewed in this context a number of invertebrates have evolved incomplete or even completely cell-lined vessels and or lacunae with a highly branched vasculature that allows for the production of significant driving pressures and flows to meet relatively high metabolic demands driven by active life styles. In light of our current understanding of invertebrate cardiovascular systems and their paralleled complexity to vertebrate systems, a number of long established paradigms must be questioned and new definitions presented to better align our understanding of the nature of “open” versus “closed” cardiovascular systems.


2002 ◽  
Vol 9 (3) ◽  
pp. 255-261 ◽  
Author(s):  
Bradley B. Hill ◽  
Yehuda G. Wolf ◽  
W. Anthony Lee ◽  
Frank R. Arko ◽  
Cornelius Olcott ◽  
...  

Author(s):  
G. I. Tikhonova ◽  
M. S. Bryleva ◽  
T. Yu. Gorchakova

Standardized mortality rates of the male population aged 15-59 in Monchegorsk, where the Kola mining and metallurgical company is located, were higher relative to the Murmansk region and Russia: from diseases of the circulatory system by 34.8% and 52.1%, respectively, from malignant neoplasms by 26.3% and 19.4%, from diseases of the digestive system by 59.0% and 36.3%.


Author(s):  
Nina M. Meshchakova ◽  
Marina P. Dyakovich ◽  
Salim F. Shayakhmetov

Introduction.Methanol and its derivatives occupy one of the leading places among the main organic synthesis intermediates in terms of their importance and scale of production. According to experts, by 2027 the global demand for methanol can reach 135 million tons, the annual growth will be about 5.5%. However, there is little information regarding the assessment of working conditions and occupational risks for workers in modern methanol production and its derivatives.The aim of the studyis hygienic assessment of working conditions and the formation of health risks in workers of modern production of methanol and methylamines.Materials and methods.The assessment of the main adverse factors of production is given. When studying the state of health, objective indicators (the results of an in-depth medical examination) and subjective (the results of a quantitative assessment of the risks of the main pathological syndromes associated with health) are considered.Results.According to long-term observations, the concentration of harmful substances in the air of the working area, indicators of labor severity, parameters of physical factors met hygienic requirements, with the exception of industrial noise exceeding the maximum permissible level, as well as labor intensity of 1 degree. The General assessment of working conditions corresponds to the category of harmful 2 degrees (3.2). According to the results of the medical examination and quantitative assessment of the risks of health disorders in workers, the most significant were functional disorders and diseases of the circulatory system. The levels of somatic pathology on the part of the main body systems were significantly higher in apparatchiks compared to the engineering and technical personnel (ETP).Conclusions:In the production of methyl alcohol and methylamines, the main hygienic importance is the impact on workers of the complex of harmful substances of 1-IV hazard classes in low concentrations, increased levels of industrial noise, labor intensity of 1 degree. According to the subjective assessment of health and medical examination, the greatest prevalence of health risks in workers was observed from the circulatory system, and the levels of the revealed somatic pathology were statistically significantly higher in apparatchiks compared with the ETP.


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