Lecture 05: Female Gonad - Oogenesis (Kelleman) Flashcards
largest cell in the body
female gamete
oogenesis =
formation of the female gamete
spermatogenesis =
formation of the male gamete
When does oogenesis arrest? ** When does it resume development?
Prophase I (late diplotene/dictyate stage). Resumes development either by LH surge during ovulation, or by hormonal control pre-ovulation. In the latter case, it will only reach metaphase II. Ultimately, fertilization must occur for oocyte to fully develop.
primordial germ cells migrate from where to where?
from yolk sac to genital ridge
PGCs undergo mitosis or meisosis?
mitosis
oogonia and how do they replicate?
PGCs that have reached genital ridge and lost their motility. 2n. Replicate by mitosis
primary oocyte
formed by meiosis of oogonia. Still 2n diploid!
folliculogenesis
formation of an antral follicle starting from a primordial follicle
follicle =
oocyte surrounded by somatic cells
difference between tertiary and Graafian follicle?
antrum has formed in Graafian follicle
What does LH control? ***
ovulation (final follicular maturation)
primordial follicle and when is it formed? **
Primary oocyte surrounded by a single layer of pregranulosa cells. Forms during fetal life
Primary follicle
oocyte surrounded by a single layer of cuboidal granulosa cells
when does zona pellucida start forming?
in primary follicle
at what stage does follicle develop independent blood supply and become sensitive to hormone regulation?
secondary follicle (early development is independent of gonadotropic hormonal support)
at what stage does theca differentiate into theca interna and externa?
tertiary follicle
FSH fx
stimulates follicular growth
LH fx
maturation of the oocyte, triggers ovulation
location of FSH receptors
granulosa cells
location of LH receptors
thecal cells, (+granulosa cells in late stages)
Two-cell-two-gonadotropin-hypothesis
thecal cells produce androgens via LH, which then diffuse into granulosa cells where they are converted to estrogens via FSH
1st meiotic division
separates homologous chromosomes. Results in two haploid daughter cells which each contain only 1 copy of each homolog
2nd meiotic division
separates the two sister chromatids from eachother. Results in 4 haploid cells