人体肺呼吸非线性动力学模型的构建及求解

发布时间：2018-10-09 13:23

【摘要】：呼吸系统是人体重要的氧气储运循环通道,依据人体生理结构可划分出近似相对独立、相对封闭的循环系统。此系统中各参量之间存在着相互作用并且处于非常复杂的正负反馈调节状态,由此促成由吸入空气而获得进入血液的氧气,到呼出二氧化碳使得肺泡内部产生负压,进而促成下一循环的吸气这样周而复始的呼吸循环运动,以维持人的生存。正常成年人平静状态下的呼吸是具有一定节律的过程,参与呼吸各参量之间正负反馈的调节控制具有非线性特征。因此可以采用探讨非线性问题的理论和方法研究其各参量之间的相互作用变化行为。已有很多的研究表明,对人体生理中相对独立的循环系统建立非线性动力学模拟,可以较好地解释其内在参量的作用规律,并与已有的实验结果相吻合。因此,根据生理系统运行机理建立相应的非线性动力学模型,来分析所研究系统的生理功能是一个新的研究热点,受到了研究人员的普遍的关注与研究,并已取得了显著的成果。正常成年人的呼吸是一种生理上自动调节运动节律的近周期过程,目前认为,呼吸过程中决定气流进出和强弱(用单位时间内肺泡体积变化率的通气量V(5)表示)的主要影响来源于两种:(1)机械作用,其包含:(1)大气压0p与肺泡内气压p之差0(35)p=p-p引起的气体流动;(2)肺泡(和气道)形变对气压差的影响;(2)化学反馈作用:主要是血液中的CO2和O2的浓度变化作用在相关感受器,后经迷走神经反馈到脑的呼吸中枢,再反过来作用在相关的呼吸肌上影响通气量V(5)的变化。本文基于人体生理结构及对临床实验结果的分析,全面地考虑呼吸系统中各参量调节控制作用及其机理,首次建立了一个人体肺呼吸系统的非线性动力学模型,并借助MATLAB计算平台求解出了此模型的周期振荡解、倍周期解和混沌解,并且在周期振荡解的合理参数基础上,通过设定特定通道参量的改变,以模拟出部分呼吸疾病的情况,得到了较为切合临床已有实验数据的模拟结果。结果表明:由所建立的人体肺呼吸系统非线性动力学模型模拟所得的各参量数值及其变化与实验研究结果一致,因此,模型是合理的。
[Abstract]:Respiratory system is an important circulation channel of oxygen storage and transportation. According to the physiological structure of human body, it can be divided into relatively independent and relatively closed circulation system. There is interaction between the parameters in this system and it is in a very complex positive and negative feedback regulation state, which causes oxygen to enter the blood by inhaling air, and the exhalation of carbon dioxide creates negative pressure in the alveoli. In turn, the next cycle of inhale, such as the repeated cycle of respiration, to maintain the survival of human beings. In normal adults, breathing is a rhythmic process, and the regulation and control of positive and negative feedback among the parameters involved in breathing have nonlinear characteristics. Therefore, the theory and method of nonlinear problems can be used to study the interaction between the parameters. Many studies have shown that the establishment of nonlinear dynamic simulation of relatively independent circulatory system in human physiology can better explain the law of the action of its internal parameters, and it is in agreement with the existing experimental results. Therefore, it is a new research hotspot to establish the corresponding nonlinear dynamic model according to the mechanism of physiological system operation to analyze the physiological function of the studied system. Remarkable results have been achieved. Breathing in normal adults is a near-periodic process that automatically regulates motion rhythms, and is now thought to be, The main effects of determining the air flow in and out of the respiratory process (expressed in terms of ventilation volume V (5) in terms of alveolar volume change rate per unit of time) come from two main sources: (1) mechanical action, It includes: (1) the gas flow caused by the difference between atmospheric pressure (0 p) and intraalveolar pressure (P) 0 (35) p=p-p; (2) the effect of alveolar (and airway) deformation on air pressure difference; (2) chemical feedback: the change of concentration of CO2 and O2 in blood is mainly affected by the related receptors. The vagus nerve fed back to the brain's respiratory center, which in turn affected the changes of ventilation V _ (5) in the related respiratory muscles. Based on the physiological structure of human body and the analysis of clinical experimental results, a nonlinear dynamic model of human lung respiratory system was established for the first time. The periodic oscillation solution, the double periodic solution and the chaotic solution are obtained by using the MATLAB computing platform. On the basis of reasonable parameters of the periodic oscillation solution, the partial respiratory disease is simulated by setting the change of the specific channel parameters. The simulation results are obtained, which are suitable for the clinical experimental data. The results show that the values and changes of the parameters obtained from the established nonlinear dynamic model of human lung and respiratory system are in agreement with the experimental results, so the model is reasonable.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R318;O322

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