hi guys my name is Mina's and today I'm going to be going over the embryo logical development of the female reproductive system and as usual I've broken it down into the most simple steps as possible so that all of these confusing drawings behind me will be broken down and fully explained so that anyone that is watching this video should be able to understand the development of a female reproductive system as usual let's begin at the beginning we begin with a blastula which is a result of fertilization where a sperm and an egg fuse and a ball of cells are made which is the blastula the blastula moves down the uterine tubes into the uterine cavity and implants into the uterine wall and a process of gastrulation will form three germ layers one ectoderm the mesoderm and the endoderm and this hamburger looking thing is an oversimplification for this in blue we have the exodor which becomes skin and nervous tissue in red we have the mesoderm and in green we have the endoderm which will become your gut tube and this is an early version of this where you see over here that the neural tube has pinched off the ectoderm and is surrounded by mezodon and that is the focus of today's video the miz' done because the middle part of the mesoderm is where the female reproductive system is from as well as the kidneys and the male reproductive but we're focusing on female reproductive the first part of the mesoderm is called the paraxial methadone which are so much or muscles the next part is the intermediate methadone and that's the focus that's where we're going to focus on in this video because female reproductive system comes from intermediate mesoderm and the third component of the mesoderm are the lateral plates which are on the outside and conform things like arteries and circulation in green we have the primitive gut you okay so this is a cross-section of the fetus this is again a cross-section of the fetus so if we have a look at these intermediate mesoderm cut it and flip it up we will have this right here don't let this confuse you this is a longitudinal view and this is a cross-sectional view where this is a single snapshot in time however this is a time lapse so the initially how the intermediate means the derm grows is from the top to the bottom from cranial to cordial from cranial to chordal and so what you have is week 1 week 2 week 3 week 4 week 5 and it keeps growing all the way to the bottom this structure are your rudimentary kidneys and they will eventually become the general tract as well as the reproductive system okay over here this long tube you'll is called the met Mezen eric ducked in purple we have the nephrogenic cord and these are all still mesoderm and tissue so the three stages of the development of this mesoderm are the pronet frosts which is a rudimentary structure it is your initial kidneys and by week forth they're gone and then we have the maser narrows which contains the Mezen eric duct otherwise known as the wolffian duct and the Mezen eric tube you'll or the wolffian tube you'll and these are the middle stage of the kidney development and this is what will contribute to becoming the female reproductive system later on and over here we have the Mitanni frost this is the final form of the kidney and that's what will remain into adulthood and grow in as a kidney okay enough with kidney let's go back and talk about the reproductive system so if we look at this fetus up here and this is a if you're looking this way at me and you cut me in half this way you'll see this as a fetus in green we have the endoderm the gut tube and in red we have the nephrogenic cord which is still intermediate mesoderm and the gonads initially appear as genital ridges on the nephrogenic cord and these general ridges they're formed by proliferation of the epithelium and the Mazin kind and so back here we have these go narrow ridges being formed and remember this is a time lapse and this is a single snapshot we have genital ridges being formed and so what happens from the epiblast from the outside we have an influx of primitive germ cells so we have germ cells coming in through the primitive streak entering the fetus and climbing through amoebic movement past the primitive gut into the dorsal mesentery and eventually with consent invading that go narrow Ridge okay so where this is following with amoebic movement have a look over here now this is to show how the germ cells invade you have these germ cells coming in through the endo dot into the dorsal mesentery and eventually in habitate in invading and inhabit ating the go natal ridge over here where the GU narrow ridges here we've kind of flipped this up and cut it so that you can see exactly what's going on and the go nano reach is a proliferation of epithelium and mesenchyme mesenchyme is just tissue it's all intermediate Me's are done but germ cells come in and join them during the germ cells moving with amoebic movement which is a little bit like this like kind of imagine if a cell can move like a caterpillar while that's happening the go narrow Ridge will proliferate waiting for them to a cup to for them to invade at this stage the fetus is neither male nor female however because the in a normal situation there is either an XX or XY chromosome the gender of the baby or the fetus is determined at fertilization now let's focus over here where we have the gonad all rich over here we're gonna take a splice out of that and bring it down here so looking at it like this where we have the aorta and the glomerulus kidney blood supply and we have this receptor looking thing which is the rudimentary kidney or the intermediate stage of the kidney the mesoamerica tubule and the mezzo narak duct this is the genital Ridge that is proliferating waiting for the germ cells to arrive and the germ cells arrive this way from the dorsal mesentery so that if we focus our attention here you'll see these germ cells invading as the primitive ovary is actually differentiating okay so where we have the invasion of these germ cells into the go narrow Ridge you'll notice that they form clusters and these clusters of germ cells with the connective tissue of the gonad will reach the epithelium that is proliferating you will have the primitive sex chord development and the primitive sex chords are initially in the medullary root region of the ovary and again they're rudimentary eventually the primitive sex chords will degenerate away and the cortical sex cords are the actual cords that remain in the ovary and become the follicular cells okay so easy steps step one step two step three step four okay so this again is section of this like that through the gonad arranged initially the genital and gonad orig are proliferating and differentiating waiting for germ cells to arrive the germ cells arrive through the dorsal mesentery and form clusters of cells with the epithelium cells of the gonad all rich the epithelial initially those clusters are primitive sex chords in the medullary region which degenerate and the cortical region will remain with the germ cells and form the sex chords so the cortical sex chords okay and over the over here this is again a longitudinal section where this is a cross-section we have over here the degeneration of the medullary chords and what happens by week 20 is at the follicular cell and the oocyte are remain because the cortical sex chords actually break down more and differentiate into them okay again the sex of the fetus isn't determined until about week 7 in the pre in the absence of a Y chromosome if the fetus is an x and x chromosome then you'll actually have the development of the ovary rather than at-st something that we haven't yet spoken about ah the parametric duct and the Mezen narak duct let's first talk about what happens to the Mezen eric duct initially it was a kidney in a male it will become epididymis a parody Damas in a female it completely degenerates in some cases it won't degenerate and remain as a proof front or a para Gouffran okay so let's just only look at Mezen eric duct step 1 step 2 step 3 the mesenteric duct will start degenerating and become an improved from or a Peru from and may remain inside a female the Ypres front is just like the epididymis in a male but serves no function in a female and the Peru front is a parody Dumas in a male but in a female again might not have any function one clinical correlation is an adenoma might present within the remnant of the Mezen narak duct so for a female in the absence of a Y chromosome the mezzo narak duct will vanish will degenerate and the paramagnetic duct will remain now the most important part of what I'm about to talk about next has to do with a paramagnetic duct the Perim is in Afric duct is pretty much created from knees are done it pinches off the back of the nephrogenic cord and joining other cells it will become a tube on both sides to simplify it at the cranial end its top end it'll remain open to the abdomen because that will eventually become the fimbriae the part of the uterine tube that picks up the oversight and brings it down into the uterus so in some ways we're starting at the beginning again where the embryo will get the oocyte the ovary and give a chance of fertilization and then bring the blastula down to the cavity but back to the development the top bit will become the fimbriae the in the middle part this part over here the majority of the pyramids in Africa duct will become the uterine tube and the core and the chordal part the bottom bit will fuse with the other side of the para mesenteric duct and become the uterine canal - quickly summer up some sum it up paramagnetic duct fimbriae uterine tubes uterus okay over here going back we have the week six indifferent gonad so just this is just to illustrate that it could either be a testes or an ovary but you can otherwise ignore that because over here we have the ovary developed and over here we begin to see the fimbriae the uterine tube and the uterus being developed okay and here we have the situation at birth where we have the ovary being suspended with the suspensory ligament and the round ligament of the uterus with the uterus here the cervix and the vagina with the furnaces surrounding the cervix okay now let's talk about uterine development we have three steps here to break it down for you guys week nine week twelve and at birth so in Week nine we already spoke about how the paramagnetic duct will join its counterpart on the other side and fuse and the uterine septa will degenerate and form a uterine cavity and this is color-coded here so in red we have paramagnetic duct and in black we have urogenital sinus and here is the uro general ridge and down at the bottom here we have the urogenital sinus and eventually what happens by week 12 is that the tip of the paramagnetic duct will invade into the urogenital sinus forming the vaginal plate which is a signer vaginal bulb it's solid tissue and eventually what happens is that the vagina will canalize which means it becomes a lumen and has a tube and at the top here the furnaces are made from paramagnetic origin and the bottom part are from urogenital sinus so the hymen is created from urogenital sinus and it consists of epithelium of also vaginal cells and uro urogenital sinus cells okay again the solid tip of the parametric duct will invade the urogenital sinus and form and form the signer vaginal bulb the so no vaginal bulb will proliferate and form a SONET solid vaginal plate and by week 20 the VAD vagina is completely canalized and the fauna sees are evident at birth the fauna sees are paramagnetic origin and the vagina is therefore derived of both paramagnetic duct and urogenital sinus the lumen of the vagina is separated from the urogenital sinus by the thin tissue called the hymen and so that is the development of the female reproductive system the second part will have the external genitalia development and to keep things simple for this video I've made it extremely simple didn't talk about molecular regulation and I've left a couple of more complex things out if you need more understanding if you need more if this video wasn't enough for you contact me and I'll send you my notes and to get a full understanding of it but I hope you've understood this easy-to-understand tutorial on the female reproductive system embryology thank you you