oogonium

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oogonium

 [o″o-go´ne-um]
[Gr.], a primordial oocyte during fetal development; near the time of birth it becomes a primary oocyte.

o·o·go·ni·um

, pl.

o·o·go·ni·a

(ō'ō-gō'nē-ŭm, -ă),
1. Primordial germ cells; proliferate by mitotic division. All oogonia develop into primary oocytes before birth occurs; no oogonia are present after birth.
2. In fungi, the female gametangium bearing one or more oospores.
[G. ōon, egg, + gonē, generation]

oogonium

(ō′ə-gō′nē-əm)
n. pl. oogo·nia (-nē-ə) or oogo·niums
1. Any of the cells that give rise through mitosis to the oocytes and are found in the ovaries of vertebrates.
2. A female reproductive structure in certain thallophytes and in oomycetes, usually a rounded cell or sac containing one or more oospheres.

o′o·go′ni·al (-nē-əl) adj.

o·o·go·ni·um

, pl. oogonia (ō'ŏ-gō'nē-ŭm, -nē-ă)
1. Primordial germ cells; proliferate by mitotic division.
2. In fungi, the female gametangium bearing one or more oospores.
[G. ōon, egg, + gonē, generation]

oogonium

  1. an early DIPLOID (1) stage in GAMETOGENESIS of female animals giving rise to the OOCYTES.
  2. (in algae and fungi) the female sex organ containing the OOSPHERES.
References in periodicals archive ?
Tilly, "Bone morphogenetic protein 4 (BMP4) promotes mammalian oogonial stem cell differentiation via Smad1/5/8 signaling," Fertility & Sterility, vol.
fortunei takes into account the presence and predominance (in the gonad) of: oogonial proliferation and entrance into meiosis; morphological changes in the ooplasm of the oocytes from the previtellogenic to vitellogenic stages; full-grown to mature oocytes and the spawning event.
fortunei Stages Steps Diagnosis Oogonial Cell nests Oogonial proliferation results in proliferation the formation of germ cell nests stage in the epithelium that lines the ovarian tubules.
However, the presence of the tissue stalk, in addition to the rounded oogonial nests throughout the gonad, strongly indicated that the specimen was female.
It is also important to point out that oogonial mitoses were identified in this study only at the beginning of the gametogenesis and NP utilization stage, but spermatogonial mitoses were observed at low levels throughout the year and at maximum levels at the same time that oogonia undergo mitosis.
The oogenesis of the two Corbicula species occurred in the oogenic or hermaphroditic follicles between the digestive and the outer fibromuscular layers and was divided into five stages: oogonial, previtellogenic oocyte, vitellogenic oocyte, and mature oocyte stages.
Gonadal maturity determined from microscopic staging of histological ovary preparations indicated maturation stages ranging from oogonial to fully vitellogenic (Table 2; Minagawa and Sano, 1997) for the females of each species.
From April through early August ovaries were in a resting state and contained oogonial nests and slightly larger oocytes with a basophilic cytoplasm and a maximum diameter of 50 [mu].