| choledochal sphincter | Smooth muscle sphincter of the common bile duct immediately proximal to the hepatopancreatic ampulla; it is this sphincter that controls the flow of bile in the duodenum. Synonym: musculus sphincter ductus choledochi, Boyden's sphincter, choledochal sphincter, sphincter muscle of common bile duct. (05 Mar 2000) |
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| microscopic sphincter | A sphincter visible only under the microscope. (05 Mar 2000) |
| midgastric transverse sphincter | Angular sphincter, thickening of the circular muscular layer forming a proposed intermediate sphincter at the level of the angular notch of the stomach. While the thickening of the circular muscle may indicate the commencement of the pyloric antrum, true functional sphincteric activity distinct from the other peristaltic contractions of the stomach is not observed although some of these may in fact temporarily close off the antrum from the remainder of the stomach lumen. Synonym: antral sphincter, midgastric transverse sphincter, sphincter antri, sphincter intermedius, sphincter of antrum, sphincter of gastric antrum. (05 Mar 2000) |
| midsigmoid sphincter | The physiological sphincter midway in the sigmoid colon. Synonym: iliopelvic sphincter. (05 Mar 2000) |
| physiological sphincter | A section of a tubular structure that acts as if it has a band of circular muscle to constrict it, although no such specialised structure can be found on morphological examination. Synonym: functional sphincter, radiological sphincter. (05 Mar 2000) |
| colic sphincter | One of the physiological sphincter's of the colon. (05 Mar 2000) |
| myovascular sphincter | A sphincter having a muscular and a vascular (usually venous) component. See: myovenous sphincter. (05 Mar 2000) |
| myovenous sphincter | A sphincter having a muscular and a venous component, e.g., at the pharyngoesophageal junction and anal canal. (05 Mar 2000) |
| postpyloric sphincter | The duodenal portion of the sphincter or closing mechanism of the gastroduodenal pylorus. (05 Mar 2000) |
| prepapillary sphincter | A sphincter of duodenum described in the location oral to the major duodenal papilla. (05 Mar 2000) |
| preprostate urethral sphincter | The complete collar of smooth muscle cells of the neck of the urinary bladder which extend distally to surround the preprostatic sportion of the male urethra. There is not a comparable structure in the neck of the femoral bladder; the internal urethral sphincter may exist to prevent reflux of semen into bladder. Synonym: annulus urethralis, internal urethral sphincter, musculus sphincter vesicae, preprostate urethral sphincter, proximal urethral sphincter, sphincter muscle of urinary bladder. (05 Mar 2000) |
| prepyloric sphincter | A band of circular muscular fibres in the wall of the stomach near the gastroduodenal pylorus. (05 Mar 2000) |
| hepatopancreatic sphincter | The smooth muscle sphincter of the hepatopancreatic ampulla within the duodenal papilla. Synonym: musculus sphincter ampullae hepatopancreaticae, Glisson's sphincter, hepatopancreatic sphincter, Oddi's sphincter. (05 Mar 2000) |
| proximal urethral sphincter | The complete collar of smooth muscle cells of the neck of the urinary bladder which extend distally to surround the preprostatic sportion of the male urethra. There is not a comparable structure in the neck of the femoral bladder; the internal urethral sphincter may exist to prevent reflux of semen into bladder. Synonym: annulus urethralis, internal urethral sphincter, musculus sphincter vesicae, preprostate urethral sphincter, proximal urethral sphincter, sphincter muscle of urinary bladder. (05 Mar 2000) |
| segmental sphincter | A sphincter of a segment of an organ, a tube, or a canal, and longer than an annular sphincter. (05 Mar 2000) |