- A tubular structure giving exit to the secretion of a gland or organ, capable of conducting fluid. SEE ALSO: canal. SYN: ductus [TA]. [L. duco, pp. ductus, to lead]- aberrant bile ducts small ducts occasionally present in the ligaments of the liver or originating from the surface of the liver.- accessory pancreatic d. [TA] the excretory d. of the head of the pancreas, one branch of which joins the pancreatic d., the other opening independently into the duodenum at the lesser duodenal papilla. SYN: ductus pancreaticus accessorius [TA], Bernard canal, Bernard d., ductus dorsopancreaticus, Santorini canal, Santorini d..- alveolar d. 1. the part of the respiratory passages distal to the respiratory bronchiole; from it arise alveolar sacs and alveoli; 2. the smallest of the intralobular ducts in the mammary gland, into which the secretory alveoli open. SYN: ductulus alveolaris.- amnionic d. the transitory opening between the seroamnionic folds in birds just before they fuse to form the seroamnionic raphe.- anal ducts short ducts lined with simple columnar to stratified columnar epithelium that extend from the valvulae anales to the sinus anales.- Bellini ducts SYN: papillary ducts.- bile d. 1. a d. formed by the union of the hepatic and cystic ducts; it discharges at the duodenal papilla. SYN: ductus choledochus [TA], choledoch d., choledoch, choledochus, common bile d.. 2. any of the ducts conveying bile between the liver and the intestine, including hepatic, cystic, and common bile d.. a d. formed by the union of the hepatic and cystic ducts; it discharges at the duodenal papilla. SYN: ductus biliaris [TA], biliary d..- Botallo d. SYN: ductus arteriosus.- bucconeural d. SYN: craniopharyngeal d..- d. of bulbourethral gland [TA] the long slender d. on each side passing down through the inferior fascia of the urogenital diaphragm to enter the bulb of the penis and course forward 2 or 3 cm before terminating in the urethra. SYN: ductus glandulae bulbourethralis [TA].- carotid d. SYN: ductus caroticus.- cochlear d. [TA] a spirally arranged membranous tube suspended within the cochlea, lying between and separating the scala vestibuli and scala tympani; it begins by a blind extremity, the vestibular cecum, in the cochlear recess of the vestibule, terminating in another blind extremity, the cecum cupulare or lagena, at the cupola of the cochlea; it contains endolymph and communicates with the sacculus by the ductus reuniens; the spiral organ (of Corti), the neuroepithelial receptor organ for hearing, occupies the floor of the d.. SYN: ductus cochlearis [TA], Löwenberg canal, Löwenberg scala, membranous cochlea, scala media.- common hepatic d. [TA] the part of the biliary d. system that is formed by the confluence of right and left hepatic ducts. At the porta hepatis it is joined by the cystic d. to become the common bile d.. SYN: ductus hepaticus communis [TA], hepatocystic d..- craniopharyngeal d. the slender tubular part of the hypophysial diverticulum; the stalk of Rathke pocket. SYN: bucconeural d., hypophysial d..- cystic d. [TA] the ductus leading from the gallbladder; it joins the hepatic d. to form the common bile d.. SYN: ductus cysticus [TA], cystic gall d..- deferent d. SYN: ductus deferens.- ejaculatory d. [TA] the d. formed by the union of the deferent d. and the excretory d. of the seminal vesicle, which opens into the prostatic urethra. SYN: ductus ejaculatorius [TA], spermiduct (2).- endolymphatic d. [TA] a small membranous canal, connecting with both saccule and utricle of the membranous labyrinth, passing through the aqueduct of vestibule, and terminating in a dilated blind extremity, the endolymphatic sac, on the posterior surface of the petrous portion of the temporal bone beneath the dura mater. SYN: ductus endolymphaticus [TA].- d. of epididymis [TA] a convoluted tube into which the efferent ductules open and which itself terminates in the ductus deferens. SYN: ductus epididymidis [TA].- excretory d. a d. carrying the secretion from a gland or a fluid from any reservoir. SYN: ductus excretorius.- excretory ducts of lacrimal gland the multiple (6–10) excretory ducts of the lacrimal gland that open into the superior fornix of the conjunctival sac. SYN: ductuli excretorii glandulae lacrimalis, excretory ductules of lacrimal gland.- excretory d. of seminal gland [TA] the passage leading from a seminal vesicle to the ejaculatory d.. SYN: ductus excretorius vesiculae seminalis [TA], excretory d. of seminal vesicle.- frontonasal d. the passage that leads downward from the frontal sinus to open into the ethmoidal infundibulum.- hemithoracic d. an accessory thoracic d., usually emptying into the thoracic d. but sometimes discharging independently into the right subclavian vein. SYN: ductus hemithoracicus.- Hensen d. SYN: ductus reuniens.- Hoffmann d. SYN: pancreatic d..- incisive d. [TA] an infrequent rudimentary d., or protrusion of the mucous membrane into the incisive canal, on either side of the anterior extremity of the nasal crest. SYN: ductus incisivus [TA].- intercalated ducts the minute ducts of glands, such as the salivary and the pancreas, that lead from the acini; they are lined by low cuboidal cells.- interlobar d. a d. draining the secretion of the lobe of a gland and formed by the junction of a number of interlobular ducts.- interlobular d. any d. leading from a lobule of a gland and formed by the junction of the intralobular ducts.- lactiferous ducts [TA] one of the ducts, numbering 15–20, which drain the lobes of the mammary gland; they open at the nipple. SYN: ductus lactiferi [TA], canalicular ducts (1), galactophore, galactophorous canals, galactophorous ducts, mamillary ducts, mammary ducts, milk ducts, tubuli galactophori, tubuli lactiferi.- left d. of caudate lobe of liver [TA] a tributary to the left hepatic d. draining bile from the left half of the caudate lobe. SYN: ductus lobi caudati sinister hepatis [TA].- left hepatic d. [TA] the d. that drains bile from the left half of the liver, including the quadrate lobe and the left part of the caudate lobe. SYN: ductus hepaticus sinister [TA].- longitudinal d. of epoöphoron [TA] a rudimentary vestige of the mesonephric d. in the female into which the tubules of the epoöphoron open; it is located in the broad ligament of the uterus, parallel with the lateral part of the uterine tube, and in the lateral walls of the cervix and vagina. SYN: ductus longitudinalis epoöphori [TA], ductus deferens vestigialis, Gartner canal, Gartner d..- Luschka ducts glandlike tubular structures in the wall of the gallbladder, especially in the part covered with peritoneum.- major sublingual d. [TA] the d. that drains the anterior portion of the sublingual gland; it opens at the sublingual papilla. SYN: ductus sublingualis major [TA], Bartholin d..- mamillary ducts SYN: lactiferous ducts.- mesonephric d. a d. in the embryo draining the mesonephric tubules; in the male it becomes the ductus deferens; in the female it becomes vestigial. SEE ALSO: longitudinal d. of epoöphoron. SYN: ductus mesonephricus, wolffian d..- metanephric d. the slender tubular portion of the metanephric diverticulum; the primordium of the epithelial lining of the ureter. See epoophoron, longitudinal d. of epoöphoron.- minor sublingual ducts [TA] from 8–20 small ducts of the sublingual salivary gland that open into the mouth on the surface of the sublingual fold; a few join the submandibular ducts. SYN: ductus sublinguales minores [TA], Rivinus ducts, Walther canals, Walther ducts.- Müller d., müllerian d. SYN: paramesonephric d..- nasolacrimal d. [TA] the passage leading downward from the lacrimal sac on each side to the anterior portion of the inferior meatus of the nose, through which tears are conducted into the nasal cavity. SYN: ductus nasolacrimalis [TA], nasal d..- nephric d. SYN: pronephric d..- pancreatic d. [TA] the excretory d. of the pancreas that extends through the gland from tail to head where it empties into the duodenum at the greater duodenal papilla. SYN: ductus pancreaticus [TA], Hoffmann d., Wirsung canal, Wirsung d..- papillary ducts the largest straight excretory ducts in the kidney medulla and papillae whose openings form the area cribrosa that open into a minor calyx; they are a continuation of the collecting tubules. SYN: Bellini ducts.- paramesonephric d. either of the two paired embryonic tubes extending along the mesonephros roughly parallel to the mesonephric d. and emptying into the cloaca; in the female, the upper parts of the ducts form the uterine tubes, while the lower fuse to form the uterus and part of the vagina; in the male, vestiges of the ducts form the vagina masculina and the appendix testis. SYN: ductus paramesonephricus, Müller d., müllerian d..- paraurethral ducts [TA] inconstant ducts along the side of the female urethra that convey the mucoid secretion of Skene glands to the vestibule. SYN: ductus paraurethrales [TA], ducts of Skene glands, Schüller ducts.- parotid d. [TA] the d. of the parotid gland opening from the cheek into the vestibule of the mouth opposite the neck of the superior second molar tooth. SYN: ductus parotideus [TA], Blasius d., Stensen d., Steno d..- pharyngobranchial ducts ductus pharyngobranchialis III, ductus pharyngobranchialis IV.- right d. of caudate lobe of liver [TA] the bile d. from the right half of the caudate lobe, a tributary to the right hepatic d.. SYN: ductus lobi caudati dexter hepatis [TA].- right hepatic d. [TA] the d. that transmits bile to the common hepatic d. from the right half of the liver and the right part of the caudate lobe. SYN: ductus hepaticus dexter [TA].- right lymphatic d. [TA] one of the two terminal lymph vessels, a short trunk, about 2 cm in length, formed by the union of the right jugular lymphatic vessel and vessels from the lymph node s of the right superior limb, thoracic wall, and both lungs; it lies on the right side of the root of the neck and empties into the right brachiocephalic vein. Frequently, no right lymphatic d. is formed, with the vessels that normally contribute to its formation entering the venous system independently. SYN: ductus lymphaticus dexter [TA], ductus thoracicus dexter.- saccular d. [TA] saccular portion of the utriculosaccular d.; extends between the sacculus and the endolymphatic d.. SEE ALSO: utriculosaccular d.. SYN: ductus saccularis [TA].- salivary d. SYN: striated d..- Schüller ducts SYN: paraurethral ducts.- secretory d. SYN: striated d..- semicircular ducts [TA] three small membranous tubes in the bony semicircular canals that lie within the bony labyrinth and form loops of about two-thirds of a circle. The three semicircular ducts: anterior semicircular d. [TA] (ductus semicircularis anterior [TA]), lateral semicircular d. [TA] (ductus semicircularis lateralis [TA]), and posterior semicircular d. [TA] (ductus semicircularis posterior [TA]), lie in planes at right angles to each other and open into the vestibule by five openings of which one is common to the anterior and lateral ducts. Each d. has an ampulla at one end within which filaments of the vestibular nerve terminate. SYN: ductus semicirculares [TA].- seminal d. any one of the ducts conveying semen from the epididymis to the urethra, ductus deferens, or ejaculatory d.. SYN: gonaduct (1).- spermatic d. SYN: ductus deferens.- striated d. a type of intralobular d. found in some salivary glands that modifies the secretory product; it derives its name from extensive infolding of the basal membrane. SYN: salivary d., secretory d..- submandibular d. [TA] the d. of the submandibular salivary gland; it opens at the sublingual papilla near the frenulum of the tongue. SYN: ductus submandibularis [TA], ductus submaxillaris, submaxillary d., Wharton d..- d. of sweat glands the superficial portion of the sweat gland that passes through the corium and epidermis, opening on the surface by the porus sudoriferus or sweat pore. SYN: ductus sudoriferus, sudoriferous d., sweat d..- testicular d. SYN: ductus deferens.- thoracic d. [TA] the largest lymph vessel in the body, beginning at the cisterna chyli at about the level of the second lumbar vertebra; the abdominal part extends superiorly to pass through the aortic opening of the diaphragm, where it becomes the thoracic part and crosses the posterior mediastinum to form the arch of the thoracic d. and discharge into the left venous angle (origin of the brachiocephalic vein). SYN: ductus thoracicus [TA], Pecquet d., van Horne canal.- thyroglossal d. [TA] a transitory endodermal tube in the embryo, carrying thyroid-forming tissue at its caudal end; normally, the d. disappears after the thyroid has moved to its definitive location in the neck; its point of origin is regularly marked on the root of the adult tongue by the foramen cecum; occasionally, its incomplete regression results in the formation of cysts along its embryonic course. SEE ALSO: pyramidal lobe of thyroid gland. SYN: ductus thyroglossus [TA], thyrolingual d..- uniting d. SYN: ductus reuniens.- utricular d. [TA] utricular portion of the utriculosaccular d.; extends between the utriculus and the endolymphatic d.. SEE ALSO: utriculosaccular d.. SYN: ductus utricularis [TA].- utriculosaccular d. [TA] a d. that connects the inner aspect of the utricle with the endolymphatic d. a short distance from its origin from the saccule. SYN: ductus utriculosaccularis [TA], Böttcher canal.
* * *duct 'dəkt n a bodily tube or vessel esp. when carrying the secretion of a gland
* * *n.a tubelike structure or channel, especially one for carrying glandular secretions.
* * *(dukt) [L. ductus, from ducere to draw or lead] a passage with well-defined walls, especially such a channel for the passage of excretions or secretions. See also entries under ductus and ductulus. ductal adj
For descriptions of anatomic structures not found here, see under ductus.
Medical dictionary. 2011.