■探索太空旅行的生理影响的早期研究表明,人体具有可逆的适应能力。然而,长期太空飞行的影响,超过6个月,提出了更复杂的挑战。
■长期暴露于微重力和辐射会对CV系统产生深远的影响。值得注意的现象包括流体向头部移动和改变的动脉压。这些变化破坏了血压调节并提高了心输出量。此外,静脉压缩的丧失导致中心静脉压的降低。
■流体从血管系统到间质的位移,由压力感受器刺激驱动,导致血浆体积下降10%-15%。
■有趣的是,尽管心脏负荷可能会增加,已经观察到心肌萎缩和血细胞比容水平的令人困惑的变化。萎缩的潜在机制似乎涉及通过mortalin介导的机制从内质网到线粒体的蛋白质合成转移。
■心律失常的实例已被反复记录,虽然一般是非致命性的,在俄罗斯和美国的太空任务中。长时间的太空飞行与QT间期的延长有关,特别是在扩展任务中。
■心脏暴露于深空的质子和重离子辐射会导致冠状动脉变性,增强的主动脉僵硬度,和颈动脉内膜通过胶原介导的过程增厚。此外,它加速动脉粥样硬化的发生并引发促炎反应。
■重新进入时,宇航员经常经历体位不耐受和改变的交感神经反应,在需要快速动员或疏散的情况下具有潜在危险。
■因此,对于即将进行的任务,必须仔细监测这些心脏风险.虽然早期的研究阐明了身体对太空旅行挑战的适应性,长期任务的复杂性及其对CV系统的影响需要继续调查和警惕,以确保宇航员的健康和任务的成功。
UNASSIGNED: Early studies exploring the physiological effects of space travel have indicated the body\'s capacity for reversible adaptation. However, the impact of long-duration spaceflight, exceeding 6 months, presents more intricate challenges.
UNASSIGNED: Extended exposure to microgravity and radiation profoundly affects the CV system. Notable phenomena include fluid shifts toward the head and modified arterial pressure. These changes disrupt blood pressure regulation and elevate cardiac output. Additionally, the loss of venous compression leads to a reduction in central venous pressure.
UNASSIGNED: The displacement of fluid from the vascular system to the interstitium, driven by baroreceptor stimulation, results in a 10%-15% decline in plasma volume.
UNASSIGNED: Intriguingly, despite potential increases in cardiac workload, cardiac muscle atrophy and perplexing variations in hematocrit levels have been observed. The mechanism underlying atrophy appears to involve a shift in protein synthesis from the endoplasmic reticulum to the mitochondria via mortalin-mediated mechanisms.
UNASSIGNED: Instances of arrhythmias have been recurrently documented, although generally nonlethal, in both Russian and American space missions. Long-duration spaceflight has been associated with the prolongation of the QT interval, particularly in extended missions.
UNASSIGNED: Exposure of the heart to the proton and heavy ion radiation pervasive in deep space contributes to coronary artery degeneration, augmented aortic stiffness, and carotid intima thickening through collagen-mediated processes. Moreover, it accelerates the onset of atherosclerosis and triggers proinflammatory responses.
UNASSIGNED: Upon reentry, astronauts frequently experience orthostatic intolerance and altered sympathetic responses, which bear potential hazards in scenarios requiring rapid mobilization or evacuation.
UNASSIGNED: Consequently, careful monitoring of these cardiac risks is imperative for forthcoming missions. While early studies illuminate the adaptability of the body to space travel\'s challenges, the intricacies of long-duration missions and their effects on the CV system necessitate continued investigation and vigilance to ensure astronaut health and mission success.