It is observed zone I and zone II, both of them localized into the head. The third zone, or zone III, comprises the distal head and all the body. The fourth and fifth zones zones IV and V , are restricted to the tail, localized into the proximal and distal Cauda epididymidis, respectively. Each zone can be readly distinguished on the basis of its own duct morphological characteristics. This distinction concerns mainly to the overall duct histology, and also to cytological appearence and epithelial lining constitution.

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Morphology of scrotum and testicle, and spermatic pathways of Metachirus nudicaudatus Geoffroy, , Didelphidae-Marsupialia. Suely F. Nogueira 3. Bruno A. Soares 4. Chaves 2. Leandra Q. Zangeronimo 2. E-mail: nogueira icb. E-mail: brunoantunes. Gonads and sperm pathways of five adult male Metachirus nudicaudatus in the reproductive phase were used to describe the morphology of scrotum, testicle, and spermatic tract. The scrotal skin is not pigmented and has few hairs and glands.

The parietal vaginal tunic is slightly pigmented. The testicles are oval and connected to the epididymis by testicular-epididymal pedicle; they are surrounded externally by the testicular capsule and supported by a stroma of connective nature. Interstitial cells are the predominant elements in abundant intertubular tissue. The seminiferous tubules are wide, meandering and surrounded by a fibro-elastic coat, containing myoid cells.

The seminiferous epithelium is composed of spermatogenic cells and Sertoli cells interspersed. The seminiferous tubules converge toward the end of the testis capitata, getting coated only support cells, featuring a transition region between the seminiferous tubules and straight tubules, occupied by a type "valve" structure that partially blocks the tubular lumen.

Straight tubules together to form a single efferent ductule, which runs a small intra-testicular extent, penetrates through the tunica and the pedicle testis-epididymis. The flexuosa part of the efferent ductule forms a separate lobe in the medial part of the body of the epididymis. The epididymis is enveloped by a capsule and epididymal comprising the epididymal duct, which is quite entangled.

The epididymal duct is lined by pseudostratified columnar epithelium with simple principal, basal, apical and "clear halo" cells. The main cells are prevalent and have morphological and histochemical differing characteristics along the duct, enabling to characterize nine different epididymal areas.

In the lumen of the seventh area top of tail that starts the pairing of sperm. This phenomenon coincides well with morphological change and a larger amount of neutral muco-substances is secreted in that area. Vas deferens has three parts: fair-epididymal, abdominal and funicular part, based on histological and histochemical changes of the epithelium and surrounding components.

The vas deferens has no bulb and even crosses the ureter before flowing into the urethra. The spermatic cord contains the vas deferens, testicular artery and veins, lymphatic vessels, nerves and developed cremaster muscle. Its components have structural changes in the proximal, middle and distal region, with a peculiar admirable network.

Sua cauda mede cerca de 30,0cm e tem pelos somente na base. B Pele escrotal com epiderme fina, sem cunhas epiteliais e sem camada papilar da derme. O asterisco mostra a cavidade vaginal. HE, 76x. HE, l92x. HE, x. A seta indica um dos pontos de desembocadura. HE, 4,5x. C A zona VII possui um lume estreito, de contorno regular. PAS, x. O ducto deferente possui lume estreito, de formato irregular e estrelado. Alcianofilia pH 2,5 foi negativa. O tecido conjuntivo que envolve o ducto permanece muito celular e bem vascularizado.

Na parte funicular, o ducto deferente possui lume estreito, de formato irregular, "estrelado". A alcianofilia pH 2,5 permanece negativa.

O tecido conjuntivo que circunda o ducto externamente permanece bastante vascularizado Fig. Todas essas estruturas encontram-se envolvidas por tecido conjuntivo e tecido adiposo unilocular. Externamente, o ducto encontra-se envolvido por uma prega peritonial. A pele escrotal de M. De acordo com Rodger em Caenolestes obscurus e Nogueira et al. Davis et al. Segundo Nogueira et al. Como descrito por Martinelli em M. Semelhante ao que acontece em outros Didelphideos Rodger , Woolley , Martinelli , exceto C.

Semelhante ao observado por Martinelli em M. Segundo Rodger , semelhante ao observado em M. Semelhante ao descrito em D. Rodger observou que, em P. O estroma intralobular de M.

Ribeiro observou em P. Segundo Jones et al. Em Tarsipes rostratus , Cummins et al. Cummins et al. Segundo alguns autores, Jones et al. Martinelli , , em M. Kelce et al. O ducto deferente de M. Na parte funicular, o ducto possui lume estreito, com formato "estrelado". Machado et al. Rodger em D. Anderson M. Paraformaldehyde-induced fluorescence as a histochemical test for 5-hidroxytryptamine in the epididymis of the opossum.

Amann R. Function of the epididymis in bulls and rams. Barbour R. Anatomy of marsupials, p. In: Stonehouse B. Eds , The Biology of Marsupials.

MacMillan Press, London. Barnes R. Reproductive system, p. In: Ibid. Academic Press, New York. Barnett C. The testicular rete mirabile of marsupials. Barros M. Revta Bras. Marsupial morphology of reproduction: South America opossum male model.

Brown D. Membrane specialization in the rat epididymis. The clear cell. Biggers J. Conjugated spermatozoa of the North American opossum. Nature Conjugated spermatozoa in American marsupials.

Reproduction in male marsupials, p. In: Rowlands I. Academic Press, London. Chase E. The reproductive system of the male opossum, Didelphis virginiana Kerr, and its experimental modification.





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