ANSC 3080 Lecture 21: Ovarian and Cycle
13 Nov 2016
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Document Summary
A large number of pgcs (oocytes) will die. Oocytes organized in cluster (cysts) surrounded by the squamous granulosa. Oocytes start meiosis and arrest in prophase i. Rodents: clusters (cysts) assembly occurs at birth. In humans and cows the process occurs mid gestation - Primordial follicles do not proliferate, population represent a female"s total reproductive potential. Process of primordial follicle formation in gonadotropin (lh; fsh) independent in mammals. In vitro: primary follicles do not arrest in prophase i. As levels of estradiol and progesterone drop just before assembly and activation, they have been proposed as being responsible for the delay and arrest. A) nest of unassembled follicles in neonatal ovary. B) primordial follicles in postnatal ovary with squamous pregranulosa cells. C) primary follicles in post natal d 4 ovary with cuboidal granolas cells. Cysts break down and oocytes surrounded by a layer of cuboidal granolas cells (assembly)= primary follicle. Once stimulated into a primary follicle the process is irreversible.
