mesonephros


mesonephros
One of three excretory organs appearing in the evolution of vertebrates; in life forms with a metanephros, the m. is located between the regressing pronephros and the metanephros, cephalic to the latter. In young mammalian embryos, the m. is well developed and briefly functional until establishment of the metanephros, the definitive kidney; in older embryos, the m. undergoes regression as an excretory organ, but its duct system is retained in the male as the epididymis and ductus deferens. SYN: middle kidney, wolffian body. [meso- + G. nephros, kidney]

* * *

me·so·neph·ros .mez-ə-'nef-rəs, .mēz-, .mēs-, .mes-, -.räs n, pl -neph·roi -.rȯi either member of the second and midmost of the three paired vertebrate renal organs that functions in adult fishes and amphibians but functions only in the embryo of reptiles, birds, and mammals in which it is replaced by a metanephros in the adult called also Wolffian body compare PRONEPHROS

* * *

n.
the second area of kidney tissue to develop in the embryo. Its excretory function only lasts for a very brief period before it degenerates. However, parts of it become incorporated into the male reproductive structures. Its duct - the mesonephric (or Wolffian) duct - persists in males as the epididymis and vas deferens, which conduct sperm from the testis.
mesonephric adj.

* * *

meso·neph·ros (mez″o-) (me″zo-nefґros) pl. mesonephґroi [meso- + Gr. nephros kidney] the excretory organ of the embryo, arising caudad to the pronephros or pronephric rudiments and using its duct; it consists of a long tube in the lower part of the body cavity, running parallel with the vertebral axis and joined at right angles by a row of twisting tubes. See also metanephros. Called also mesonephron, middle kidney, and wolffian body. mesonephric adj

Medical dictionary. 2011.

Look at other dictionaries:

  • Mesonephros — Reconstruction of a human embryo of 17 mm. (Label for Mesonephros is at center right.) Gray s …   Wikipedia

  • mésonéphros — ● mésonéphros nom masculin Formation rénale embryonnaire des vertébrés amniotes, remplacée chez l adulte par le rein définitif ou métanéphros. mésonéphros [mezonefʀos] n. m. ÉTYM. 1897, l Année biol., XIV, p. 276; de méso , et nephros « rein ». ❖ …   Encyclopédie Universelle

  • mesonephros — [mes΄ə nef′räs΄, mez΄ə nef′räs] n. [ModL < meso ,MESO + Gr nephros, kidney: see NEPHRO ] the excretory organ serving as the adult kidney of fishes and amphibians and as the embryonic kidney of higher vertebrates: the mesonephros and its duct… …   English World dictionary

  • Mesonephros — Mes o*neph ros, n. [NL., fr. Gr. me sos middle + nefro s kidney.] (Anat.) The middle one of the three pairs of embryonic renal organs developed in most vertebrates; the Wolffian body. [1913 Webster] …   The Collaborative International Dictionary of English

  • Mesonephros — Mesonephros, s. Nieren …   Meyers Großes Konversations-Lexikon

  • Mesonephros — ⇒ Urniere …   Deutsch wörterbuch der biologie

  • Mésonéphros — Le mésonéphros est un organe excréteur rudimentaire qui se développe chez les vertébrés. Chez les mammifères, les oiseaux et les reptiles il représente le deuxième des trois appareils rénaux différents qui se succèdent pendant la vie utérine.… …   Wikipédia en Français

  • mesonephros — the functional organ of excretion with a large number of tubules in all adult fishes except Myxini. Arises in the middle portion of the body cavity but extends backwards to the entire length of body cavity, and is deflected ventrally on the… …   Dictionary of ichthyology

  • Mesonephros — Urniere eines Hühnerembryos am 4. Bebrütungstag. Links davon liegt die Genitalleiste (Genital ridge) Als Urniere (Mesonephros, „Wolffscher Körper“) bezeichnet man die zweite Nierengeneration in der Entwicklung bei Wirbeltieren. Ihre Bildung… …   Deutsch Wikipedia

  • mesonephros — mesonephric, adj. /mez euh nef ros, mes , mee zeuh , seuh /, n., pl. mesonephroi / roy/. Embryol. one of the three embryonic excretory organs of vertebrates, becoming the functional kidney of fishes and amphibians and becoming part of the tubules …   Universalium

  • Mesonephros — tarpinis inkstas statusas T sritis gyvūnų raida, augimas, ontogenezė, embriologija atitikmenys: lot. Mesonephros ryšiai: platesnis terminas – šlapimo organai siauresnis terminas – mezonefriniai vamzdeliai siauresnis terminas – tarpinio inksto… …   Veterinarinės anatomijos, histologijos ir embriologijos terminai


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.