Zachoval R, Záleský M, Lukes M, Mares J, Urban M, Palascak P
Urologická klinika 3. LF UK Praha.
Cesk Fysiol. 2000 Aug;49(3):134-44.
The lower urinary tract provides two modes of operation--storage and elimination of urine. The normal function results in the coordination of contraction and relaxation of muscles of the urinary bladder and urethral sphincters. Disorders of these activities or their interaction lead to the development of lower urinary tract dysfunctions. The nervous system plays an essential role in the regulation of the functions. The control of micturition is coordinated by several regious of the central nervous system. Afferents and efferents of the peripheral nervous system carry signals from and to the lower urinary tract. The reflex circuitry controlling micturition consists of five components: spinal efferent neurons, peripheral efferent neurons, primary afferent neurons, spinal interneurons and neurons in the brain. Preganglionic neurons located in the sacral parasympathetic nucleus and lumbar sympathetic nucleus excite the peripheral efferent neurons innervating smooth muscles of the urinary bladder and urethra. Motoneurons of sacral Onuf's nucleus excite the striated muscle of the external urethral sphincter. Myelinated and unmyelinated afferent axons transmit information from the lower urinary tract to the lumbosacral spinal cord. Three receptor types of the lower urinary tract are present: tension receptors, volume receptors and "silent receptors", which become nociceptors following the sensitization. Afferent pathways terminate on spinal interneurons. Spinal interneurons relay information to the brain or to other regions of the spinal cord. Because micturition reflexes are mediated by disynaptic or polysynaptic pathways, interneuronal mechanisms are of crucial importance in the regulation of lower urinary tract. Central pathways involved in micturition reflexes are located in spinal and supraspinal areas. Micturition reflexes can be modulated at the level of the spinal cord by viscero--bladder and somato--bladder reflexes. Supraspinal areas have a more complicated organization: critical component of the micturition reflex is the pontine micturition center and the periaqueductal gray. Inhibitory and excitatory areas in the pontomedullary and hypothalamic systems and the brain play an important role in the regulation of micturition reflexes.
下尿路具有两种运作模式——尿液储存和排出。正常功能依赖于膀胱和尿道括约肌肌肉收缩与舒张的协调。这些活动或其相互作用的紊乱会导致下尿路功能障碍的发生。神经系统在这些功能的调节中起着至关重要的作用。排尿控制由中枢神经系统的多个区域协调。外周神经系统的传入和传出神经将信号传至下尿路及从下尿路传出。控制排尿的反射通路由五个部分组成：脊髓传出神经元、外周传出神经元、初级传入神经元、脊髓中间神经元和脑内神经元。位于骶副交感核和腰交感核的节前神经元兴奋支配膀胱和尿道平滑肌的外周传出神经元。骶部奥努夫核的运动神经元兴奋尿道外括约肌的横纹肌。有髓和无髓传入轴突将下尿路的信息传至腰骶脊髓。下尿路存在三种受体类型：张力受体、容量受体和“沉默受体”，后者在敏化后成为伤害感受器。传入通路终止于脊髓中间神经元。脊髓中间神经元将信息传递至脑或脊髓的其他区域。由于排尿反射由双突触或多突触通路介导，中间神经元机制在调节下尿路功能中至关重要。参与排尿反射的中枢通路位于脊髓和脊髓以上区域。排尿反射可在脊髓水平通过内脏-膀胱和躯体-膀胱反射进行调节。脊髓以上区域的组织结构更为复杂：排尿反射的关键组成部分是脑桥排尿中枢和导水管周围灰质。脑桥延髓和下丘脑系统以及脑中的抑制性和兴奋性区域在排尿反射的调节中起重要作用。
