| Full text | |
| Author(s): |
Oliveira, C. de
[1]
;
Santos, L. R. de S.
Total Authors: 2
|
| Affiliation: | [1] Universidade Estadual Paulista (UNESP). Campus de São José do Rio Preto. Instituto de Biociências, Letras e Ciências Exatas. Departamento de Biologia - Brasil
Total Affiliations: 2
|
| Document type: | Journal article |
| Source: | Revista Brasileira de Zoologia; v. 21, n. 4, p. 919-923, dez. 2004. |
| Field of knowledge: | Biological Sciences - Morphology |
| Abstract | |
This paper describes morphological characteristics of the ovarian germinative cells of the Scinax fuscovarius (Lutz, 1925). The ovary is organized in primordial germinative cells (oogonia) and follicular structures (ovarian follicle) - oocytes surrounded by follicular cells. Oogonia: their nests are peripherically localized, containing cells with large and oval nucleus. Oocytes I: basophilic cytoplasm; the spherical nucleus presents few nucleoli, one or two; the follicular cells (one tenuous layer) surround these previtellogenic cells. Oocytes II: the cell is larger and the cytoplasm becomes more basophilic; the nucleus presents few nucleoli and contains many chromosomes in the periphery (beginning the perinucleolar stage). Oocytes III: the cytoplasm acquires an intense acidophilia; the peripherical region of cytoplasm is filled with yolk and the internal region has no yolk at all; pigment synthesis begins; the follicular envelope presents three tenuous layers: an inner acellular (vitelline envelope) and two cellular layers (follicle cells). Oocytes IV: a characteristic of this stage is the differentiation between the animal and the vegetal poles; the nucleus in the animal hemisphere and the pigments give the oocyte a color dark brown; the vitellogenesis is intense and the yolk occupies the whole cytoplasm. (AU) | |