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a passage with well-defined walls, especially a tubular structure for the passage of excretions or secretions. adj., adj ductal.
accessory duct of Santorini a tubular structure that drains the lower part of the head of the pancreas.
alveolar d's small passages connecting the respiratory bronchioles and the alveolar sacs.
Bartholin's duct (duct of Bartholin) the larger and longer of the sublingual ducts.
bile d's (biliary d's) see bile ducts.
cochlear duct a spiral membranous tube in the bony canal of the cochlea between Reissner's membrane and the basilar membrane; it is divided into the scala tympani, scala vestibuli, and spiral lamina. Called also scala media.
common bile duct a duct formed by the union of the cystic and hepatic ducts; see also bile ducts.
cystic duct the passage connecting the gallbladder neck and the common bile duct.
efferent duct any duct that gives outlet to a glandular secretion.
ejaculatory duct the duct formed by union of the ductus deferens and the duct of the seminal vesicles, opening into the prostatic urethra on the colliculus seminalis.
endolymphatic duct a canal connecting the membranous labyrinth of the ear with the endolymphatic sac.
excretory duct one through which the secretion is conveyed from a gland.
hepatic duct the excretory duct of the liver, or one of its branches in the lobes of the liver; see also bile ducts.
lacrimal duct the excretory duct of the lacrimal gland; see also lacrimal apparatus. Called also lacrimal canaliculus.
lacrimonasal duct nasal duct.
lactiferous d's ducts conveying the milk secreted by the lobes of the breast to and through the nipples.
lymphatic duct, left thoracic duct.
lymphatic d's see lymphatic ducts.
mammary duct lactiferous ducts.
mesonephric duct an embryonic duct of the mesonephros, which in the male becomes the epididymis, ductus deferens and its ampulla, seminal vesicles, and ejaculatory duct, and in the female is largely obliterated.
müllerian duct either of the two paired embryonic ducts developing into the vagina, uterus, and fallopian tubes, and becoming largely obliterated in the male.
nasal duct (nasolacrimal duct) the downward continuation of the lacrimal sac, opening on the lateral wall of the inferior meatus of the nose; see also lacrimal apparatus.
pancreatic duct the main excretory duct of the pancreas, which usually unites with the common bile duct before entering the duodenum at the major duodenal papilla; see also bile ducts.
papillary d's straight excretory or collecting portions of the renal tubules, which descend through the renal medulla to a renal papilla.
paramesonephric duct müllerian duct.
paraurethral d's Skene's glands.
parotid duct the duct by which the parotid glands empty into the mouth.
prostatic d's minute ducts from the prostate, opening into or near the prostatic sinuses on the posterior wall of the urethra.
lymphatic duct, right a vessel draining lymph from the upper right side of the body, receiving lymph from the right subclavian, jugular, and mediastinal trunks when those vessels do not open independently into the right brachiocephalic vein.
salivary d's the ducts of the salivary glands.
semicircular d's the long ducts of the membranous labyrinth of the ear.
seminal d's the passages for conveyance of spermatozoa and semen.
sublingual d's the excretory ducts of the sublingual salivary glands.
submandibular duct (submaxillary duct) the duct that drains the submandibular gland and opens at the sublingual caruncle.
tear duct lacrimal duct.
thoracic duct a duct beginning in the cisterna chyli and emptying into the venous system at the junction of the left subclavian and left internal jugular veins. It acts as a channel for the collection of lymph from the portions of the body below the diaphragm and from the left side of the body above the diaphragm.
either of the two paired embryonic ducts extending along the mesonephros roughly parallel to the mesonephric duct and emptying into the cloaca; in the female, the upper parts of the ducts form the uterine tubes, whereas the lower fuse to form the uterus and part of the vagina; in the male, vestiges of the ducts form the prostatic utricle and the appendix testis.
Etymology: Johannes P. Müller, German physiologist, 1801-1858
one of a pair of embryonic ducts that become the fallopian tubes, uterus, and vagina in females and that atrophy in males, resulting in formation of the prostatic utricle.
Müllerian ductAn embryonic structure that, in females, develops into the ducts of the reproductive system. The Müllerian duct degenerates in the male under the influence of the protein Müllerian inhibiting substance. (Johannes Peter Müller, German physiologist and comparative anatomist, 1801–58).
Mullerian ductthe duct from the embryonic PRONEPHROS which in later development in mammals becomes the oviduct in females and disappears in males. It is named after the German anatomist and physiologist Johannes Müller (1801–58).
müllerian duct, Muellerian duct
either of the paired embryonic paramesonephric ducts developing into the vagina, uterus and uterine tubes, and becoming largely obliterated in the male or retained as the uterus masculinus or prostatic utricle. Named after J.P. Müller, a German physiologist.
müllerian duct aplasia
the ovaries cycle normally and the lumen of the tube oral to the obstruction distends with secreted fluids. The lumen may be obstructed at any location along its length, including only one horn; the commonest form is hymenal persistence. Called also 'white heifer disease'.
müllerian duct inhibitory factor
produced by the Sertoli cells in the developing testis; causes müllerian duct regression, a key step in sexual differentiation.