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An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell (PGC), which then undergoes mitosis, forming oogonia. During oogenesis, the oogonia become primary oocytes. An oocyte is a form of genetic material that can be collected for cryoconservation.
The primary oocyte is defined by its process of ootidogenesis, which is meiosis. [2] It has duplicated its DNA, so that each chromosome has two chromatids, i.e. 92 chromatids all in all (4C). When meiosis I is completed, one secondary oocyte and one polar body is created. Primary oocytes have been created in late fetal life.
Renal fibrosis is the result of failed kidney healing and associated with renal dysfunction, [206] but it was suggested that it might support survival of non-injured and partially injured nephrons. [207] Chronic kidney injury is characterized by fibrosis, scarring, and loss of tissue function. [48]
During oogenesis, the oogonia become primary oocytes. Oocytes (immature ova) residing in the primordial follicle of the ovary are in a non-growing prophase arrested state, but have the capacity to undergo highly efficient homologous recombinational repair of DNA damages including double-strand breaks. [ 1 ]
A simple means of estimating renal function is to measure pH, blood urea nitrogen, creatinine, and basic electrolytes (including sodium, potassium, chloride, and bicarbonate). As the kidney is the most important organ in controlling these values, any derangement in these values could suggest renal impairment.
Spermatogonia going through mitosis to form primary spermatocytes in Grasshopper testes. Spermatocytogenesis. At puberty, spermatogonia located along the walls of the seminiferous tubules within the testis will be initiated and start to divide mitotically, forming two types of A cells that contain an oval shaped nucleus with a nucleolus attached to the nuclear envelope; one is dark (Ad) and ...
The zona pellucida is a translucent matrix of cross-linked glycoprotein filaments that surrounds the mammalian oocyte and is 6.5–20 μm thick depending on the species. Its formation, which depends on a conserved zona pellucida-like (ZP) module that mediates the polymerization of egg coat components, [2] is critical to successful fertilization. [3]
The secondary oocyte undergoes meiotic division II and that results in the formation of a second small polar body and a large mature egg, both being haploid cells. The polar bodies degenerate. [12] Oocyte maturation stands by at metaphase II in most vertebrates. During ovulation, the arrested secondary oocyte leaves the ovary and matures ...