AIM:To study the relationship between the radiologicalanatomy and the dynamics on bile duct sphincter in biledraining and regulatory effect of gallbladder.METHODS:Sixteen healthy dogs weighing 18 kg to 25 kgwere divided randomly into control group and experimentalgroup (cholecystectomy group).Cineradiography,manometrywith perfusion,to effect of endogenous cholecystokinin andchange of ultrastructure were employed.RESULTS:According to finding of the choledochography andmanometry,in control group the intraluminal basal pressureof cephalic cyclic smooth muscle of choledochal sphinctercCS was 9.0±2.0 mmHg and that of middle oblique smoothmuscle of choledochal sphincter (mOS) was 16.8±0.5 mmHg,the intraluminal basal pressure of cCS segment was obviouslylower than that of mOS (P<0.01) in the interval period ofbile draining,but significant difference of intraluminal basalpressure of the mOS segment was not found between theinterval period of bile draining (16.8±0.5 mmHg) and thebile flowing period (15.9±0.9 mmHg) (P>0.05).The motilityof cCS was mainly characterized by rhythmically concentriccontraction,just as motility of cCS bile juice was pumpedinto the mOS segment in control group.And motility of mOSsegment showed mainly diastolic and systolic activity ofautonomically longitudinal peristalsis.There was spasmodicstate in cCS and mOS segment and reaction to endogenouscholecystokinin was debased after cholecystectomy.Thechange of ultrastructure of cCS portion showed mainly thatthe myofilaments of cell line in derangement andmitochondria is swelling.CONCLUSION:During fasting,the cCS portion has afunction as similar cardiac “pump” and it is main primarypower source in bile draining,and mOS segment servesmainly as secondary power in bile draining.The existenceof the intact gallbladder is one of the important factors inguaranteeing the functional coordination between the cCSand mOS of bile duct sphincter.There is dysfunction in thecCS and mOS with cholecystectomy. AIM: To study the relationship between the radiologicalanatomy and the dynamics on bile duct sphincter in biledraining and regulatory effect of gallbladder. METHODS: Sixteen healthy dogs weighing 18 kg to 25 kgwere divided randomly into control group and experimentalgroup (cholecystectomy group) .Cineradiography, manometrywith perfusion, to effect of endogenous cholecystokinin and change of ultrastructure were employed .RESULTS: According to finding of the choledochography andmanometry, in control group the intraluminal basal pressure of cephalic cyclic smooth muscle of choledochal sphinctercCS was 9.0 ± 2.0 mmHg and that of middle oblique smoothmuscle of choledochal sphincter (mOS) was 16.8 ± 0.5 mmHg, the intraluminal basal pressure of cCS segment was significantly lower than that of mOS (P <0.01) in the interval period ofbrain draining, but significant difference of intraluminal basalpressure of the mOS segment was not found between theinterval period of bile draining (16.8 ± 0.5 mmHg) and thebile flowing (15.9 ± 0.9 mmHg) (P> 0.05). The motility of cCS was mainly characterized by rhythmically concentric contraction, just as motility of cCS bile juice was pumpedinto the mOS segment in control group. End motility of mOSsegment showed mainly diastolic and systolic activity ofautonomically longitudinal peristalsis. was was spasmodicstate in cCS and mOS segment and reaction to endogenouscholecystokinin was debased after cholecystectomy. The change of ultrastructure of cCS portion showed primarily that the myofilaments of cell line in derangement and mitochondria is swelling. CONCLUSION: During fasting, the cCS portion has afunction as similar cardiac “pump ” and it is main primarypower source in bile draining, and mOS segment servesmainly as secondary power in bile draining.The existence of the intact gallbladder is one of the important factors inguaranteeing the functional coordination between the cCSand mOS of bile duct sphincter.There is dysfunction in thecCS and mOS with cholecystectomy.