State-space analysis of a myocybernetic model of the lower urinary tract
State-space analysis of a myocybernetic model of the lower urinary tract
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DOI：
10.1006/jtbi.1996.0098
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发表时间：
1996-06-07
影响因子：
2
通讯作者：
vanLeeuwen, JL
中科院分区：
文献类型：
--
作者：
Bastiaanssen, EHC;Vanderschoot, J;vanLeeuwen, JL
为了研究下尿路的控制，分析了Bastiaanssen等人（1996）的肌控制模型的状态空间。该模型能够响应来自神经网络的输入信号，并且包括膀胱壁中的逼尿肌和尿道括约肌的肌肉动力学的描述。恒定输入信号的模型的平衡状态被发现通过计算的流量曲线的根的评价。可以区分两种类型的平衡状态：（i）膀胱的流入和流出都等于零，以及（ii）膀胱流入和流出都等于从输尿管到膀胱的规定的小恒定流量。第一种类型的平衡特征是非常高的膀胱压力，这在体内可能导致尿液回流到输尿管中。第二种类型表现为尿液的不断流失。对于不同的恒定输入信号组合，发现了两种类型的几种稳定平衡状态，神经控制器应避免这些状态，使下尿路既能完成其储存功能，又能完成其排泄功能。因此，在此评估通过模拟正常充盈和排尿事件的状态空间的轨迹。它出现的平衡状态，避免了输入信号的快速变化。正常轨迹外的模型的行为进行了比较，神经泌尿道疾病。一些病理行为与模型预测定性一致。(C)1996年学术出版社
To study the control of the lower urinary tract, the state space of the myocybernetic model by Bastiaanssen et al. (1996) is analysed. This model is able to respond to input signals from a neural network and includes descriptions of the muscle dynamics of both the detrusor in the bladder wall and the urethral sphincter. The equilibrium states of the model for constant input signals were found by evaluation of the roots of calculated flow curves. Two types of equilibrium states could be distinguished: (i) the inflow and the outflow of the bladder are both equal to zero and (ii) the bladder in- and outflow are both equal to a prescribed small constant flow from the ureters into the bladder. The first type of equilibrium features a very high bladder pressure, which in vivo could result in a reflux of urine into the ureters. The second type shows a constant loss of urine. For different combinations of constant input signals, several stable equilibrium states of both types were found. The neural controller should avoid these states so that the lower urinary tract fulfils either its storage or its voiding function. Therefore, the trajectory through the state space of a simulated normal filling and micturition event was evaluated here. It appeared that equilibrium states were avoided by rapid changes of the input signals.The behaviour of the model outside the normal trajectory is compared with neurologic urinary tract disorders. Several pathological behaviours are in qualitative agreement with the model predictions. (C) 1996 Academic Press Limited