Описание: Environmental heat stress is associated with a marked decrease in orthostatic tolerance (OT), which is defined as the ability to stand or sit upright without symptoms of dizziness, lightheadedness, presyncope, or fainting. In most healthy humans, the autonomic nervous system makes rapid and balanced adjustments to heart rate and peripheral blood flow, such that most people are able to stand up ""successfully"" most of the time, in most environments. The goal of this book is to discuss various aspects of the sympathetic neural response to heat stress, how the sympathetic nervous system coordinates the successful integrative physiological response to orthostasis, and what happens when it encounters both challenges simultaneously. We include overviews of mechanisms of thermoregulation and blood pressure regulation in humans, with particular focus on control of cardiac output and neurovascular control mechanisms during heat stress. We discuss the implications that these changes have for distribution of peripheral blood flow and, in particular, for blood flow to the cerebral circulation. The added stressor of dehydration is also discussed, as it so often goes hand in hand with heat stress. We end with a brief presentation of countermeasures against the decreases in OT with heat stress.
Автор: K.O. Stumpe; Karin Kraft; Alan I. Faden Название: Opioid Peptides and Blood Pressure Control ISBN: 3540189351 ISBN-13(EAN): 9783540189350 Издательство: Springer Рейтинг: Цена: 15372 р. Наличие на складе: Есть у поставщика Поставка под заказ.
Описание: A. , FADEN, K. KRAFr, and K. O. STUMPE Following the discovery of the pentapeptide enkephalins in 1975, a number of endogenous opioid peptides and opiate receptors have been identified. Endogenous opioids and opiate-receptor mechanisms have been implicated in a variety of regulat- ory and dysregulatory functions including analgesia, cardiovascular regulation, shock, hypertension, traumatic spinal cord and brain injury, stroke, immune func- tion, feeding behavior, diuresis, gastrointestinal motility, and respiratory control, among others. Over the past 10 years, many studies have demonstrated a relationship between endogenous opioids and the cardiovascular system under both homeostatic and pathophysiological conditions. Opioids and opiate receptors have been found in various cardioregulatory sites within the brain and spinal cord, as well as in peripheral tissues such as sympathetic ganglia, adrenal gland, and heart. Both endogenous opioids and exogenous opiates have been shown to produce potent cardiovascular effects following central nervous system or systemic administration. Opiate-receptor antagonists have been demonstrated to reverse hypotension from sepsis, hypo- volemia, and anaphylaxis; such studies have been used to infer activity of endogenous opioid systems in shock. Changes in tissue concentrations of endogenous opioids and or opiate receptors have been found after shock and hypertension, further implying a role for opioid systems in the etiology of these conditions. In addition, modification of opiate receptor regulation, receptor binding, or opioid metabolism has also been used to establish a potential role for endogenous opioid systems in cardiovascular control and dyscontrol.
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