Oogenesis Flashcards
What are oogonia?
a primordial oocyte in a female foetus
How are oogonia formed?
When are they formed?
formed in large numbers by mitosis early in foetal development
proliferate between the 9th and 22nd week of foetal development
At what stage of meiosis are primary oocytes arrested in until puberty?
prophase 1
contrasts with male primordial germ cells which are arrested in the spermatogonial stage at birth and do not enter meiosis to produce primary spermatocytes until puberty
What is oocytogenesis?
the process of developing oogonia, which occurs via the transformation of primordial follicules into primary oocytes
What is ootidogenesis?
primary oocyte ==> ootid
process begins at prenatal age but stops at prophase 1
at puberty these cells continue to develop but only a few do so every menstrual cycle
dictyate - prolonged resting phase of oogenesis
What stage of meiosis II is the secondary oocyte halted at until fertilisation?
metaphase II
What makes up an ovarian follicle?
an oocyte surrounded by granulosa cells
What happens at the first stage of the ovarian cycle?
corresponds with days 1-7 of menstrual cycle - menses
6 - 12 primary oocytes begin to mature
When does the zona pellucida first appear?
in primary oocytes
What is the follicle that gets ovulated called?
the dominant follicle
What is atresia?
the process by which all the follicles that are not the dominant follicle die off
What is a polar body?
a polar body is formed when the primary oocyte divides to form two daughter cells which have an equal number of chromosones but inequal division of the cytoplasm
polar body gets the least amount of cytoplasm so it cannot be a functional oocyte
it degenerates and dies
What cell type is ovulated from the ovary?
secondary oocyte
What hormone causes the oocyte to mature?
FSH
What part of the ovum releases inhibin to decrease levels of FSH?
granulosa cells
