失重条件下人体心血管系统反应的仿真研究

发布时间：2018-03-20 22:50

本文选题：失重　切入点：仿真　出处：《第四军医大学》2005年硕士论文　论文类型：学位论文

【摘要】：航天飞行时人体处于失重或微重力环境,流体静压消失,体液头向分布,返回地面1G环境后,将对人体心血管系统产生不利影响,造成心血管功能失调,主要表现为立位耐力下降。失重或微重力环境下心血管功能失调的机制是复杂的、多方面的,主要有以下几种原因:心功能下降,心输出量较飞行前仰卧位时降低10%～20%;失重引起反射性多尿,水盐从尿中排出,使血容量减少;脑血流降低;下肢静脉顺应性增加等。以往开展的失重或模拟失重实验表明,血容量的减少将引起类似于失血时心血管系统的变化。另外失重后体液头向分布,约有2000 ml血液由下肢转移到上身,对脑血流将产生显著影响,引起脑血流速度和压力感受器调节的改变。这些因素将直接影响血压和血流量的变化。因此,研究失重时人体血压、血流量的变化可为研究心血管功能失调的机理提供指导。针对这方面的研究已经开展很多,大多采用在航天飞行和在地面模拟等方法研究失重对人体的影响,人体和动物的实验方法成为主要的研究手段,并取得了一定的进展。但是,由于受到客观条件的限制,很难获得理想的研究条件,许多指标在现有的条件下难以获得,而且采取人体实验的方法开展研究对人体损伤大,动物实验又不能完全适用人体。针对人体和动物实验的不足,近年来广泛开展了对这一领域的计算机仿真研究,以弥补实验的不足。本研究在借鉴以往研究的基
[Abstract]:When the human body is in a weightlessness or microgravity environment during space flight, the hydrostatic pressure disappears, the body fluid head distributes in the direction of the body fluid, and the body fluid returns to 1 gigabyte environment on the ground, which will have adverse effects on the cardiovascular system of the human body and cause cardiovascular dysfunction. The mechanism of cardiovascular dysfunction in weightlessness or microgravity environment is complex and multi-faceted, mainly due to the following reasons: decreased cardiac function. Cardiac output is 10 / 20 lower than that in supine position before flight; weightlessness causes reflex polyuria, water and salt are excreted from urine, resulting in decreased blood volume, cerebral blood flow is decreased, and lower extremity venous compliance is increased, etc. Previous weightlessness or simulated weightlessness experiments have shown that. The decrease in blood volume will cause changes similar to those in the cardiovascular system during blood loss. In addition, after weightlessness, the head of the body fluid is distributed in the direction of about 2000 ml of blood transferred from the lower extremities to the upper body, which will have a significant effect on the cerebral blood flow. These factors will directly affect the changes of blood pressure and blood flow. Therefore, the study of changes in blood pressure and blood flow during weightlessness can provide guidance for the study of the mechanism of cardiovascular dysfunction. Many researches have been carried out in this field, most of them are used to study the effects of weightlessness on human body in space flight and simulation on the ground. The experimental methods of human body and animals have become the main research means, and have made some progress. Due to the limitation of objective conditions, it is difficult to obtain ideal research conditions, and many indexes are difficult to obtain under the existing conditions. In view of the deficiency of human and animal experiments, computer simulation research in this field has been carried out extensively in recent years in order to make up for the deficiency of experiment.
【学位授予单位】：第四军医大学
【学位级别】：硕士
【学位授予年份】：2005
【分类号】：R85

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