Intro to Female embryology and oogenesis Flashcards
what are gametes derived from
primordial germ cells (PGCs)
where are primordial germ cells formed
they are formed in the epiblast during the second week and that move to the wall of the vitellus sac.
where do the primordial germ cells migrate to after four weeks
toward the developing gonads
what happens when PGCs arrive at the gonads of a female
they differentiate into oogonia
what happens to the oogonia by the end of the third month
they are arranged in clusters surrounded by a layer of epithelial cells, the flat epithelial cells, known as follicular cells, originate from surface epithelium covering the ovary
what happen to the oogonia by the end of the 7th month
majority of oogonia have degenerated except for a few near the surface
what is a primordial follicle
A primary oocyte, together with its surrounding flat epithelial cells
what is the diplotene stage
a resting stage during prophase which oocytes enter
what produces the arrested state of primary oocytes
oocyte maturation inhibitor (OMI), a small peptide secreted by folicular cells
what happens as primordial follicles begin to grow
surrounding follicular cells change from flat to cuboidal and proliferate to produce a stratified epithelium of granulosa cells, and the unit is called a primary follicle
what do the Granulosa cells and the oocyte secrete
a layer of glycoproteins on the surface of the oocyte, forming the zona pellucida
what extends across the zona pellucida and interdigitate with microvilli of the plasma membrane of the oocyte
small, finger-like processes of the follicular cells, important for transport of materials from follicular cells to the oocyte
Granulosa cells rest…….
on a basement membrane separating them from surrounding ovarian connective tissue (stromal cells) that form the theca folliculi
what happens as follicles continue to grow
cells of the theca folliculi organize into an inner layer of steroid secretion cells and rich in blood vessels, the theca interna, and an outer fibrous capsule, gradually merges with the ovarian connective tissue, the theca externa
what does merging of the theca interna and externa form
antrum, and the follicle is termed a vesicular or an antral follicle
