排便和克制排便是直肠和肛门的主要生理功能。这两个看起来似乎相反的功能由大脑皮层对腰骶段脊神经有意识的支配所协调。排便是一连惯的肠道运动，起自排便意识，引起由脑干中枢所调控的一系列盆底反射。基本的排便控制功能与生俱有，较高级的皮层活动由后天“训练”产生。静 Defecation and defecation are the main physiological functions of the rectum and anus. These seemingly opposite features are coordinated by the conscious cortex of the lumbosacral spinal nerves. Bowel movement is a habit of bowel movement, from the awareness of bowel movements, causing a series of pelvic floor reflex regulation by the brainstem center. Basic defecation control is inherent and higher cortical activity results from acquired “training.” Static