Ultrastructure and morphometry of ovarian follicles in the armadillo Chaetophractus villosus (Mammalia, Dasypodidae)

Abstract

Ultrastructural and morphometric changes in oocyte and surrounding granulosa cells during armadillo follicular growth are described. Primordial, intermediary, early and late primary, secondary, tertiary and preovulatory Graafian follicles were found. From primordial to Graafian follicle, granulosa cells increase in height, become multilayered while fluid-filled spaces arise among them in the tertiary follicle stage. As the follicle expands the oocyte is located eccentrically and grows in size. From primordial to secondary stage organelles develop in number and complexity and many vesicles start arising in the cytoplasm at the secondary stage. From tertiary follicle stage the number of mitochondria decreases. In follicular cells, secreting-related organelles expand, but mitochondrial number decreases according to the follicle expansion. Intercellular junctions between both cell types increase. The morphometrical study shows a biphasic pattern of oocyte and follicle growth. The morphological baseline here provided will be essential for further comprehension of the reproductive biology in armadillos.

Follicular development in the volcano mouse (Neotomodon alstoni alstoni, Rodentia: Muridae) from birth to maturity: A morphological approach

“…The findings in the volcano mouse, that as the follicle matures there is a positional change of the oocyte nucleus from centric to slightly eccentric, and an increase in complexity of its cytoplasm with the formation of filamentous and vesicular bodies, among which lipid droplets are found, are common phenomena in the follicular development of mammals (Fleming and Saacke 1972; Fair et al . 1997; Codón et al . 2001).…”

The Spleen of a Specialy Adapted Mammal: The Little Hairy Armadillo Chaetophractus vellerosus, (Xenarthra, Dasypodidae). A Light and Electron Microscopic Study

“…In spite of these remarks, the morphology, physiology, ecology and conservational status of the group are poorly known and only some work exists about genus Chaetophractus Estecondo & Casanave, 1999;Polini et al, 1999;Codón et al, 2001;Maldonado et al, 2002, Bermúdez et al, 2004Casanave et al, 2005Casanave et al, , 2006. The little hairy armadillo C. vellerosus shows a physiological adaptation to semiarid environments (Greegor, 1975) but only some studies about this species have been published (Greegor, 1980;Estecondo et al, 1997;.…”

Biologia da reprodução em tatus: análise morfológica do aparelho reprodutor feminino da espécie Euphractus sexcinctus e análise morfológica placentária comparativa entre as espécies Chaetophractus villosus, Chaetophractus vellerosus e Euphractus sexcinctus

“…O folículo secundário é caracterizado pela contínua proliferação de células foliculares, chamadas de camada granulosa, e pelo espessamento da zona pelúcida que separa a camada granulosa do oócito (BANKS, 1992;CODÓN et al, 2001;KIERSZENBAUM, 2008). No folículo terciário observa-se o antro folicular e menor número de mitocôndrias (BANKS, 1992;CODÓN et al, 2001). Hamlett (1932) Os remanescentes embrionários existentes na região medular são parte da "rete ovarii", homólogo feminino da "rete testis", que são cordões sólidos e curtos de células epiteliais (BANKS, 1992).…”

“…, 1977b;SEIFERLE, 1979;GETTY, 1986). Sua morfologia oval assemelhou-se ao descrito por (NEWMAN, 1912;HAMLETT, 1935;CODÓN et al, 2001;MARCOS;MERANI, 2005) , 1947;SCHUMMER, 1977;GETTY, 1986). Embora outros estudos tenham feito referência às redes admiráveis (ARRUDA, 1995;ARRUDA;ARRUDA, 1999) ;GOSLOW, 2006;KARDONG, 2007).…”

“…A estabiliade morfológica tem sido interpretada, com base na genética molecular, como sinal de maturidade evolutiva. Considerando-se as descrições de autores mais rescentes CASANAVE, 2000;CODÓN et al, 2001;MARCOS;MERANI, 2005) GRASSÉ, 1955;REISS, 2001;NARITA;KURATANI, 2005;HILDEBRAND;GOSLOW, 2006).…”