now follicle-stimulating hormone is doing something to a follicle so let's just do a really quick and brief description of what is this follicle you speak of well first of all a follicle is a structure in the ovary that surrounds some flavor of a site think back on the process of meiosis and remind yourself that within one of the stages of oogenesis the process of producing a fertile egg one of the stages is to go through and create a primary oo site it's pretty fascinating how the ladies actually freeze their like mitotic cells like the cells that are going to go through the process of meiosis there are only 500,000 of them in each ovary and that's not very many and they get frozen in meiosis they get stuck in this primary oocyte stage and they're stuck inside something called a primordial follicle and I'm drawing little flat cells around this Oh site to show you that this is a primordial follicle Prime that's an R I'm or deal follicle now follicle-stimulating hormone who do you think the follicle-stimulating hormone is stimulating follicle and I'm not gonna go into all the crazy details we'll avoid those crazy details you can go to Anatomy to look for those but I'm just gonna do like a really quick like from here over the course of 14 days and under the influence of follicle stimulating hormone the follicle is going to grow luteinizing hormone plays a role as well and we'll talk about that in a second inside my follicle even after 14 days I'm gonna still have a oside of some flavor but now it's actually a secondary oocyte and it's sitting inside a mature follicle so I'm gonna draw you a mature follicle and you'll see I mean I'm not even gonna do it any semblance of justice because mature follicles are gigantic at the beginning of the cycle follicle stimulating hormone stimulates I mean up to 20 follicles out of your 500,000 in your ovary to start to develop and as the process goes along over the course of 14 days not all of them usually it's just one who reaches the stage of the mature follicle and there's a whole bunch of processes in between here so the mature follicle is surrounded by a type of cell called a granulosa cell there's a reason I've done it in green I'm going to tell you that follicle stimulating hormone stimulates granulosa cells and so my granulosa cells are what I'm drawing right now in green and take a deep breath because you'll see in a second why I'm drawing it like this this is a mature follicle and fees right here are all my cells and you agree that they are like little square cuboidal looking little cells and don't they look like oh they're ready to do some jobs here and I'm just trying to show you that their layers and layers of cells and looks like layers and layers of cells and right here inside here this is a space called the antrum and there's fluid in here and actually the granulosa cells are producing that fluid like they're growing really fast why are they growing they're growing really fast because of the follicle stimulating hormone they're also growing really fast because they're producing more hormones Oh ovarian hormones like we're gonna have another whole story that we have to talk about here there aren't just granulosa cells there are also cells called fecal cells not fecal cells fecal cells and LH is the hormone that gets the fecal cells going the fecal cells are the guys that are going to produce estrogen so look that fecal cells surround the outside of the mature follicle now primordial follicles I mean we might draw like some little like baby lines like oh yeah there's some precursor out there but really the thecal cells start to develop with the influence of follicle-stimulating hormone they start to develop now I think that what we want to talk about is who is being produced by my fecal cells these guys are going to produce estrogen how am I gonna do that I'm gonna go like this and say that they're gonna produce estrogen and if you can imagine that we started out with like none and we end up with whoa there's a lot of them because that's a huge mature follicle and all those outer cells are producing estrogen and the interesting thing is that they produce a molecule that then diffuses into the granulosa cells and the granulosa cells do like some modification and like give it a kiss and now it becomes actual estrogens so the granulosa cells and fecal cells are working together to produce the estrogen but what are you gonna expect to happen to the levels of estrogen in your system as this happens okay well let's go talk about estrogen but of course