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Author: Thomas F.H. Schmidt
Publisher: Springer Science & Business Media
ISBN: 3662027488
Category : Medical
Languages : en
Pages : 413
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Book Description
Although it is widely recognized that there are significant variations in the circulation throughout the 24-hour day, these patterns have often been conceived as nuisance variables rather than functional differences. Responses of the circulation are examined here not as stable phenomena, but as integrated functions highly sensitive to environmental conditions, and driven by internal and external pacesetters. In this volume, cardiologists with a primary interest in hypertension or heart disease, chronobiologists, and psychologists join together for the first time to give the reader the opportunity to learn the extent and clinical significance of these changes from a chronobiological, behavioral and physiological perspective.
Author: Thomas F.H. Schmidt
Publisher: Springer Science & Business Media
ISBN: 3662027488
Category : Medical
Languages : en
Pages : 413
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Book Description
Although it is widely recognized that there are significant variations in the circulation throughout the 24-hour day, these patterns have often been conceived as nuisance variables rather than functional differences. Responses of the circulation are examined here not as stable phenomena, but as integrated functions highly sensitive to environmental conditions, and driven by internal and external pacesetters. In this volume, cardiologists with a primary interest in hypertension or heart disease, chronobiologists, and psychologists join together for the first time to give the reader the opportunity to learn the extent and clinical significance of these changes from a chronobiological, behavioral and physiological perspective.
Author: Roland N. Pittman
Publisher: Biota Publishing
ISBN: 1615047212
Category : Medical
Languages : en
Pages : 117
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Book Description
This presentation describes various aspects of the regulation of tissue oxygenation, including the roles of the circulatory system, respiratory system, and blood, the carrier of oxygen within these components of the cardiorespiratory system. The respiratory system takes oxygen from the atmosphere and transports it by diffusion from the air in the alveoli to the blood flowing through the pulmonary capillaries. The cardiovascular system then moves the oxygenated blood from the heart to the microcirculation of the various organs by convection, where oxygen is released from hemoglobin in the red blood cells and moves to the parenchymal cells of each tissue by diffusion. Oxygen that has diffused into cells is then utilized in the mitochondria to produce adenosine triphosphate (ATP), the energy currency of all cells. The mitochondria are able to produce ATP until the oxygen tension or PO2 on the cell surface falls to a critical level of about 4–5 mm Hg. Thus, in order to meet the energetic needs of cells, it is important to maintain a continuous supply of oxygen to the mitochondria at or above the critical PO2 . In order to accomplish this desired outcome, the cardiorespiratory system, including the blood, must be capable of regulation to ensure survival of all tissues under a wide range of circumstances. The purpose of this presentation is to provide basic information about the operation and regulation of the cardiovascular and respiratory systems, as well as the properties of the blood and parenchymal cells, so that a fundamental understanding of the regulation of tissue oxygenation is achieved.
Author: Marilyn J. Cipolla
Publisher: Biota Publishing
ISBN: 1615047239
Category : Medical
Languages : en
Pages : 82
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Book Description
This e-book will review special features of the cerebral circulation and how they contribute to the physiology of the brain. It describes structural and functional properties of the cerebral circulation that are unique to the brain, an organ with high metabolic demands and the need for tight water and ion homeostasis. Autoregulation is pronounced in the brain, with myogenic, metabolic and neurogenic mechanisms contributing to maintain relatively constant blood flow during both increases and decreases in pressure. In addition, unlike peripheral organs where the majority of vascular resistance resides in small arteries and arterioles, large extracranial and intracranial arteries contribute significantly to vascular resistance in the brain. The prominent role of large arteries in cerebrovascular resistance helps maintain blood flow and protect downstream vessels during changes in perfusion pressure. The cerebral endothelium is also unique in that its barrier properties are in some way more like epithelium than endothelium in the periphery. The cerebral endothelium, known as the blood-brain barrier, has specialized tight junctions that do not allow ions to pass freely and has very low hydraulic conductivity and transcellular transport. This special configuration modifies Starling's forces in the brain microcirculation such that ions retained in the vascular lumen oppose water movement due to hydrostatic pressure. Tight water regulation is necessary in the brain because it has limited capacity for expansion within the skull. Increased intracranial pressure due to vasogenic edema can cause severe neurologic complications and death.
Author: J. Gordon Betts
Publisher:
ISBN: 9781947172807
Category :
Languages : en
Pages : 0
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Book Description
Author: United States. Public Health Service. Office of the Surgeon General
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 728
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Book Description
This report considers the biological and behavioral mechanisms that may underlie the pathogenicity of tobacco smoke. Many Surgeon General's reports have considered research findings on mechanisms in assessing the biological plausibility of associations observed in epidemiologic studies. Mechanisms of disease are important because they may provide plausibility, which is one of the guideline criteria for assessing evidence on causation. This report specifically reviews the evidence on the potential mechanisms by which smoking causes diseases and considers whether a mechanism is likely to be operative in the production of human disease by tobacco smoke. This evidence is relevant to understanding how smoking causes disease, to identifying those who may be particularly susceptible, and to assessing the potential risks of tobacco products.
Author: Michael Lüdinghausen
Publisher: Springer Science & Business Media
ISBN: 364255623X
Category : Medical
Languages : en
Pages : 112
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Book Description
The objective of this study is to present comprehensive morphological data, almost all of it is new, concerning the venous drainage of the myocardium via the coronary sinus and its related veins. This information is of great significance, not least for the sucessful coronary sinus catheterization and reperfusion of most, or single, cardiac veins.The author presents the three principal cardiac venous systems, the greater (major) cardiac venous, the smaller (minor) cardiac venous system, and the compound venous system. The work concludes with an evaluation of the many anatomical peculiarities and and hindrances with regard to the catheterization of the coronary sinus and the reperfusion of (selected) cardiac veins.
Author: André Aubert
Publisher: Springer Science & Business Media
ISBN: 9401108722
Category : Medical
Languages : en
Pages : 441
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Book Description
In 1992, clinical cardiac electrophysiology became a recognized sub-speciality of the American Board of Internal Medicine. The formal recognition of this highly specialized and technical field of medicine represents the culmination of thirty years of remarkable scientific and intellectual discovery. Beginning in the 1950s, cardiologists realized that cardiac arrhythmias were the cause of significant morbidity and the sudden death of at least 350,000 patients every year in the United States alone. At that time the only tools available for analyzing abnormal heart rhythms were the standard EKG machine and careful deductive reasoning. During the early 1960s, cardiac pacemakers reflected the first foray in the electrical therapy of cardiac arrhythmias. Pacemakers were first implanted in order to control syncopal episodes related to bradycardic heart rhythms. Although crude and bulky devices, their utility was immediately obvious to physicians and patients alike. The recognition that electrical signals could be recorded from inside the heart and that the heart's rhythm could be controlled by the application of electrical energy began the era of clinical cardiac electrophysiology which was to follow. In the late 1960s and early 1970s and at the peak of the Vietnam conflict. a group of cardiologists with special training in cardiac electrophysiology were sequestered at the US Public Health Service Hospital at Staten Island.
Author: M. Di Rienzo
Publisher: IOS Press
ISBN: 9789051991581
Category : Medical
Languages : en
Pages : 340
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Book Description
CHAPTER 17: Respiratory Pattern, Invested Effort, and Variability in Heart Rate and Blood Pressure During the Performance of Mental Tasks -- CHAPTER 18: Power Spectra of Blood Pressure in Normotensive and Spontaneously Hypertensive Rats: Relationship with Sympathetic Cardiovascular Control -- CHAPTER 19: Sympathectomy, Sinoaortic Denervation and Spectral Powers of Blood Pressure and Heart Rate in Lyon Rats -- CHAPTER 20: Heart Rate Variability in Chronic Heart Failure -- CHAPTER 21: Spectral Analysis of Blood Pressure and Heart Rate in Patients with Myocardial Infarction -- CHAPTER 22: Heart Rate Variability and Sudden Death: What's the Connection? -- CHAPTER 23: Power Spectrum Analysis of Heart Rate in Diabetic. Patients: A Marker of Autonomic Dysfunction -- References -- Author Index
Author: Karin Trimmel
Publisher: Frontiers Media SA
ISBN: 2889196526
Category : Physiology
Languages : en
Pages : 168
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Book Description
Over the last decades, assessment of heart rate variability (HRV) has increased in various fields of research. HRV describes changes in heartbeat intervals, which are caused by autonomic neural regulation, i.e. by the interplay of the sympathetic and the parasympathetic nervous systems. The most frequent application of HRV is connected to cardiological issues, most importantly to the monitoring of post-myocardial infarction patients and the prediction of sudden cardiac death. Analysis of HRV is also frequently applied in relation to diabetes, renal failure, neurological and psychiatric conditions, sleep disorders, psychological phenomena such as stress, as well as drug and addiction research including alcohol and smoking. The widespread application of HRV measurements is based on the fact that they are noninvasive, easy to perform, and in general reproducible – if carried out under standardized conditions. However, the amount of parameters to be analysed is still rising. Well-established time domain and frequency domain parameters are discussed controversially when it comes to their physiological interpretation and their psychometric properties like reliability and validity, and the sensitivity to cardiovascular properties of the variety of parameters seems to be a topic for further research. Recently introduced parameters like pNNxx and new dynamic methods such as approximate entropy and detrended fluctuation analysis offer new potentials and warrant standardization. However, HRV is significantly associated with average heart rate (HR) and one can conclude that HRV actually provides information on two quantities, i.e. on HR and its variability. It is hard to determine which of these two plays a principal role in the clinical value of HRV. The association between HRV and HR is not only a physiological phenomenon but also a mathematical one which is due to non-linear (mathematical) relationship between RR interval and HR. If one normalizes HRV to its average RR interval, one may get ‘pure’ variability free from the mathematical bias. Recently, a new modification method of the association between HRV and HR has been developed which enables us to completely remove the HRV dependence on HR (even the physiological one), or conversely enhance this dependence. Such an approach allows us to explore the HR contribution to the clinical significance of HRV, i.e. whether HR or its variability plays a main role in the HRV clinical value. This Research Topic covers recent advances in the application of HRV, methodological issues, basic underlying mechanisms as well as all aspects of the interaction between HRV and HR.
Author: Peter H. Redfern
Publisher: Springer Science & Business Media
ISBN: 3662093553
Category : Medical
Languages : en
Pages : 682
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Book Description
Measured by any criteria, research in chronobiology in general and chronopharmacology in particular has expanded rapidly in recent years. This expansion has been paralleled by an increasing recognition by those outside the field of the relevance and significance of recent developments in chronobiology. Advances in two areas have been chiefly responsible. First, application of the full range of modern techniques in behavioral, neurochemical, and molecular biology have greatly improved our understanding of basic clock mechanisms. In several species the genetic basis of the circadian clock is being progressively delineated. A complete picture of the neurochemical and neuroanatomical structure of the mammalian clock is emerging and the complex pattern of control mechanisms involving endogenous clock mechan isms and photic and nonphotic zeitgebers is being built up as a result of behavioral studies. Secondly, in parallel with these exciting developments in basic science, clinical applications are being convincingly demonstrated in the general fields of pharmacology and medicine as well as in specific areas, e.g., jet lag, shiftwork maladaption syndrome, blindness, and cardiovascular system. It is therefore an opportune time to review progress in the field of chronopharmacology and to introduce some of the exciting developments and prospects to a readership beyond the confines of the chronobiological cognoscenti. This volume is therefore aimed primarily at the pharmacologist - whether basic, applied, or clinical-who is not a specialist in chronobiology.
