排便的生理和便秘的病理生理

慢性便秘可以看作是不同病理生理过程的最终症状表现 ,其胃肠运动主要出现以下病理生理变化 :( 1)结肠运动功能异常 :表现为运动亢进、减弱、不协调。结肠非推进性收缩幅度、频率增加 ,肠传输时间延长 ,肠内容物水分吸收过多 ,粪便干燥 ;结肠推进性收缩的幅度频率减少、结肠蠕动无力 ,肠传输时间增加 ,粪便无法正常推送至直肠 ;不协调运动 ,结肠某一部分收缩增强、逆向蠕动 ,影响传输时间 ;( 2 )直肠运动异常 :直肠张力下降 ,顺应性增加 ,感觉功能下降 ;( 3 )肛门括约肌功能异常 ;( 4 )盆底肌群收缩功能下降 ,持续收缩、不协调收缩或松弛。本文对排便的生理和便秘的病理生理进行综述

Physiology of defecation and pathophysiology of chronic constipation

Chronic constipation may be a result of varied p athophysiological action.Abnormalities associated with chronic constipation are as follows:(1)The colonic motility disorders.The colon contraction frequency and amplitude without propelling movement increases,the transit time prolonged,wate r in the bowel content is excessively absorbed,which produces a hard stool;The c olon contraction frequency and amplitude with propelling movement decreases,the transit time prolonged,the feces cannot be pushed to the rectum;The local dishar mony contraction and reverse peristalsis of the colon make dyssynergic defecatio n.(2)The rectal motility disorders.The rectum tension and sensitivity reduce,and compliance increases.(3)Dysfunction of the anal sphincter.(4)Abnormal contracti on of muscle groups in the pelvic floor such as declined or persistent contracti on,disharmony contraction and relaxation.The article reviewed the physiology of defecation and pathophysiology of constipation.