Structure and function of the external urethral sphincter (EUS)

1)在人尿道的电镜观察中，前列腺部尿道周围叶的髓质内有丰富的肾上腺素能自主神经。这些肾上腺素能纤维进一步下行，作为自主神经传出纤维到达EUS，在那里它们形成所谓的表面连接，表明肾上腺素能参与人EUS的功能。2）超微结构上似乎有三种类型的横纹肌-两种类型的红肌和一种类型的白色肌。3）在神经源性排尿功能障碍中，通过肌电图评估的EUS活动与膀胱输尿管返流和相关肾瘢痕的严重程度相关。神经源性膀胱中EUS的肾上腺素能激活似乎是引起逼尿肌-括约肌-协同失调（DSD）的部分原因，DSD是这些受试者中排尿功能障碍的主要原因。5）根治性TURP通过与壁内外科交感神经切除术等效的作用缓解DSD来缓解排尿功能障碍。

1) On electron microscopic study of human male urethra there was a rich supply of autonomic adrenergic nerves in the interstitium of peripheral lobe of the prostatic urethra. These adrenergic fibers descended further more as autonomic efferents to the EUS, Wherein they formed so called surface junctions, suggesting adrenergic involvement in the function of human EUS.2) Ultrastructurally there seem to be three types of striated muscle - two types of red muscle and one type of white muscle.3) In neurogenic voiding dysfunction the activity of EUS as assessed by its electromyography was correlated ot the severity of vesicoureteral feflux and associated renal scarring.4) Alpha-adrenergic activation of EUS in neurogenic bladder seems to be partially responsible for the genesis of detrusor-sphincter-dyssynergia(DSD), a leading cause of voiding dysfunction among these subjects.5) Radical TURP relieves voiding dysfunction by relieving DSD through ist effects equivalent to intramural surgical sympathetectomy.