hi and welcome hopefully to the very last video you ever have to watch in any of my classes so we will finish off embryology I hope it won't take too long and I just wanted to show you my shirt something to always remember I know it's backwards but it says if at first you don't succeed try doing what your Anatomy teacher told you to do so there you go I had a student give that to me a few years back and I really like it so I thought it was an appropriate thing message to leave you with as we finish up bio 202. all right so we're going to take a look at how that two layered so this is what you were before let me draw what you were before so on the top you were a layer of cells I'm doing you in cross-section like head on face or long cross I don't know yeah cross section here would be the amnion here with your amniotic cavity that's the amnion right here and then this is the epiblast right here okay then you have this yellow layer of cells as the hypoblast and then whoops he had the yolk sac all right so that's what you were before but now they're epiblast is going to turn into three primary we call them germ because if you think about what does germy means to grow and to germinate so um uh that's that's where everything is going to grow from so like it says the cells from which all body tissues develop so this epiblast layer right here is going to go into ectoderm mesoderm and endoderm okay you should know two out of these three terms ectoderm that's where we got our nervous system from so when we talked about um uh how your spinal cord formed it formed from ectoderm there on your back mesoderm we talked about mesenchyme so one kind of messenger mesoderm is mesenchyme and you guys absolutely know what mesenchyme is that's what all connective tissues come from so bones and and blood and fibroblast so the loose and dense connective tissues in the cartilages um so you know ectodermino messenger and so now you're just now we've got a new thing with endoderm but we'll be going into what are all what are the derivatives of each layer so all the things we have in our body now what did they and did they come from all right so we I'm trying to think if I want to show let's look at picture first all right here is you so what's going to happen so this is the epiblast is a hypoblastic we thought what's going to happen is that the epiblast is going to fold over inside and make a little dip now this is not your nervous system dip that's going to come later but this is going to form what's known as the Primitive streak and so all the cells are going to migrate so you can see how we got these little Folds so they fold in and then cells are going to migrate through that primitive streak and we have um so we have this um opening up here and this well this just aligns our head to tails of cephalic cuddle head tail um or eventually we're going to have a mouth we're gonna have an anus first because we are deuterostomes and so we start with an anus and then we build up to a mouth that's kind of funny but but anyway um so we're going to come back to this picture in a little bit more in a minute so that was the Primitive streak all right and then we have um a cephalic end primitive pit we have a caudal end too and then the invagination cells are going to detach from the epiblast and then they're going to migrate through that primitive streak between the epiglast and the hypoblast II become these three um tissues so the endoderm are epiblast cells that displace the hypoblast come push it out of the way and take its place mesoderm will be a new layer that we didn't ever have before and then the ectodermis just the cells that stay on the top of the epiblast all right so we saw that here is that migration so now we have the cells migrating in forming the endoderm so early week three so we're like on easily day 16 day 17. okay and then we're going to keep migrating so we've got the endoderm replaced the this is not hypoblast anymore this is endoderm tissue that came from the epiblast in the middle and then this section right here so this has become Endo I mean mesoderm okay so that's in the middle and that's how I always remember mesoderm so so we're like at day 19 right here day 20. somewhere in there that we have this mesoderm forming so I have ectoderm on the outside here mesoderm in the middle and endoderm on the inside so this is going to form your gut So eventually that hole in the middle of your gut that's your is going to come from this endoderm um all right so let's go back here and look at our notes okay so uh we're not going to worry too much I think I I don't know I can't remember if I put this in the in your notes or not oh I think I did Okay so here you are just so without that lined here in pink is you we call it the embryonic disc so you are a flat sheet of three types of cells and in fact with the ectoderm and the mesoderm I mean the ectoderm and the endoderm that's only one layer of cells you can see they look like simple columnar epithelium so you get one layer of cells and then you have a few multiple layers in the in the mesoderm and then another layer of the endoderm so we need to turn you into a baby because you're just a sheet you're just three sheets of paper is basically what you're doing so you are this flattened disc shaped three-way old embryo so now we're at the start of the fourth week is where we're heading and then um right here so we get two types of folding what you're going to do is cephalocado and transverse and I may um get out of here if you let's see I'm I'm just going to show you this all right so here's what we're going to do we're going to take this sheet and we're going to curve it up so we're going to curve it up like this and then we're going to take the caudal end and we're going to curve it in and curve it in and so now you have a head end and a tail end but you're so let me here let me show you what that looks like all right so your three sheets of paper all right this is you so you're these nevermind let's do it this way so you're this three sheets of paper so we're gonna have our our cotton or our cranial end on here and this is our caudal end and so what we're going to do is curve you up this way okay now you have a head and now you have a tail okay so that's what we're gonna do the caudal uh whatever cranial folding okay we're gonna fold you like that now here is the most amazing thing ever in the whole world because your body knows that that folding is gonna go on let me just show you we put your brain what is eventually going to be your brain okay we stick it up here in what's going to be your head but above it we build the tissue for what is that ah it's a heart so that when we fold it your brain is where your brain is going to be in your head and look at where's your heart it's in your chest where it's supposed to be I think that's amazing when I learned that I was like you've got to be kidding me that heart tissue started to form anterior to your brain tissue because later on your body knew that you were gonna get put your heart was going to get put in your chest region just like that oh my gosh friends that is the most amazing thing ever all right so that's your um cranial caudal folding then we're going to fold you transversely no and when we fold you transversely oh you guys I'll just do it like this okay so now we've folded you transversely and what we're gonna this is now your thoracic and abdominal cavity pelvic cavity so this is all your ventral body cavity and now we're going to descend that endoderm inside of there because here is your endodermis the third layer that's the inner I would love to just teach an embryology class for like a whole semester okay so here is your endoderm so that's going to come down here and then when you pinch it off then and you fold it like this then you have your gut tube suspended in the middle of your abdominal cavity again so amazing how did we know we were going to do that one day we'll find out okay so we'll go back to sharing okay so um there we go so we have the cephalic and the cuddle and rapid growth of embryonic disc and amnion no growth of the yolk Sac we are not going to do that anymore and then we that causes because we want those to curl around so we have to grow them big okay so we want them to to um curve around like that so we lots of growth lots of growth and it pinches up like that and then you can see oh we're gonna we're getting our little yolks back in here and we're getting a gut tube developing right there so that's going to cause the head and tail to fold in on itself all right then so we've already folded head to tail now we've got to fold in the middle so these are the sides so we're going to do this lateral folding or transverse folding and as we fold what we're going to do is pinch together so here is the cavity right here okay here's our cavity this is all over inside of our body oh look there is our peritoneal cavity that's so awesome and then here's mesentery and here's our gut so we pinch this off we're making mesentery out of that and then um uh no it comes from right here and um then we have you know the mesentery that holds your intestines to the back of your abdominal cavity and then there's your abdominal organs they're all gonna are all gonna um be modifications off of your uh your uh um endoderm right there okay so then the right and left sides curve towards the midline pinch off the oak Sac um makes a cylindrical embryo now so ectoderm is on the outside endoderm is now on the inside instead of being on the bottom and then the oak Sac pinches off from most of the endoderm except you have this fiddling duct which is eventually going to be present in your um um in your uh no because it's still the viddling duct is in your umbilicus and so you still have to have your connection to your mom so even we fold over but we we still persist that bitly induction and then like I said create it creates your torso so this is going to make your um uh thoracic and abdominal cavities all right so now what we're going to do is make what we're going to make out of our three germ layers so the first one we're going to take a look at is ectoderm and ectoderm is now on the outside surface of our cylindrical embryo so remember that we were a tube where an entire tube and we're going to make a tube in the tube and so it's responsible for forming the nervous system tissue which we already know in a process called neuralation so what is going to come from ectoderm and we could spend days and days and days talking about neurolation but we kind of did when we did nervous system back into a one so just remember these things are going to come from ectoderm so the epidermis obviously because it's on the external surface of the embryo our sense organs why are sense organs because they grow from your brain so that nervous tissue that makes up your brain is going to sprout and it's going to sprout out to become your sense organs it's going to come down to form your pituitary gland posterior pituitary in particular but here's the funky part so the posterior pituitary is going to come down from your brain okay but where the anterior pituitary come it came from the in the back your throat yeah it just grew back up into your head and then it matched up because that was epithelial tissue that's glandular and so then it Formed with the nervous tissue of your posterior pituitary oh so cool then Adrenal medulla what did we have we had neurons that that um neural crest cells that migrated out stuck themselves inside the adrenal cortex which is going to come from mesoderm and then didn't differentiate into neurons anymore they just said hey you know what we're going to release epinephrine and norepinephrine as a gland instead of neurons because we can shoot it out into the bloodstream and we can get to a whole bunch of places even though it might take a little bit longer we can get to a whole lot more places with a whole lot less effort as far as Anatomy is concerned I don't have to have neurons to my to my sympathetic organs I I do but that extra boost is going to come from the hormones as you know enamel of your teeth why the enamel of your teeth well because it's the outside part of your teeth and then why that lens of your eye you think well it's on the inside how does that work it wasn't always on the inside your eye was a cup and then cut from the back from your brain and then the outside surface ectoderm formed the lens of your eye and it just kind of sat inside of the cup and then and then the rest of this epithelium on the outside on the external surface then covered it over so so yeah it's pretty cool that your eye was once upon a time of cup okay so if we take a look at this um there's exactly the same stuff if you read in this box of ectoderm um that's what you need to know so epidermis of the skin epidermal derivative so anything that comes from the epidermis obviously hair nail sweat glands memory glands okay because we know that that's all those are all epidermal derivatives nervous tissue and sense organs pituitary gland adrenaline in both sides of the pituitary because one is going to be surface ectoderm ones can be neuroelectoderm but you don't have to wade into the weeds that much and Adrenal medulla no longer takes lens of your eye okay all right so now we're going to go down to mesoderm so we'll come back to this picture but let's go into mesoderm so mesoderm is going to become a bunch of different stuff um all right so um the very first thing that comes first oh early early is what's known as the notochord and nodochord is a bunch of mesodermal cells that are going to be pretty thick pretty um stiff okay and this notochord is the basis of vertebrates so all vertebrates started out with a notochord embryonically every single one of them so the the simplest fish um we call them tunicates and we have and they're not even fish they're um they're chordates they're vertebrates but um they kind of look like fish but they're not even fish they're their own their own thing not tunicates um is that something else uh I can't remember so anyway for just pretend simple simple simple simple simple fish and then fish amphibians reptiles birds and mammals so everything has a notochord and the notochord is stuck back there even before your nervous system forms and remember your nervous system form starts on starts on day 16. so you get a notochord super super early and what that does is make you know that you have the center part of your body and where your axial skeleton is going to come from so your skull and your vertebrae of your axial skeleton and the only part we have left of our nodal cord because it kind of just gets absorb into our body is in the middle of our intervertebral discs so our our axial skeleton our vertebrae form around our notochord by the time we're born but um there is still a remnant of that original notochord in the inner vertebral discs okay and it by having that note accord then and then it says hey you know what maybe you should form a nervous system and then you start to get that in folding so it's going to be below right where you get that neural Groove happening just immediately underneath that will be that nodal cord all right you're not going to need to remember paraxial mesoderm but I do want you to know that there is going to be mesoderm so I want you to know this whole chunk right here um okay so this are these we're going to have soul mites little bodies not little but bodies they're block like masses and I'm going to show you what a soulmate looks like in just a minute and this is how we're related to earthworms because earthworms have segmented bodies and embryonically we had segmented bodies and there are sections in those somites that are going to give rise to the skeleton muscle cartilage dermis and the rest of connective tissues in that segment of your body so let's go back here to where we had an embryo that had somites on it there we go okay see all these little blocks right here they look like they're vertebrae but they're not these are the somites and so what the somites are going to do is you have a um in your soulmates you have a skeletal component you have a dermal component and a muscle component and so muscular whatever and so let's take this little s this First Sunlight right here okay all the skin muscle and bone connective tissue that's going to come in this section of your body will grow from that soulmate and then you're going to have this only and that will grow that and then here and then here and then here and so so you have these little seeds in the back of you that are then going to grow out and build that section of you that they Encompass okay now remember we had dermatomes remember we said we had a dermal component of it dermatomes remember those are the things with shingles those are the things that if we touch it then we know whether we're anesthetized or not or that's when we're going to control the muscle that comes out of that spot so that's what why they come our dermatomes come in lines like that it's being oh and nervous and then the nervous will follow so the nervous is not part of a soulmate but the somite will pull the nervous tissue with it and so that's how we get innervated into these little segments of our skin oh my gosh you guys Soul mites are the best thing in the world I love them but all I need you to know about Soul mics is we get to soul mates all right so the somites then are these chunks of tissue that run along your neural tube okay pound or both sides of your neural tubes that's why we have bilateral symmetry um why we have right and left halves when we do a mid sagittal section is because of the somites and so they're going to form our axial skeleton or muscle cartilage dermis connective tissue so our bone and everything I don't know why they didn't put bone so our appendicular skeleton too comes um soulmates okay so there you go so that's mesoderm some of the mesoderm then what else does mesoderm forms your kidneys ureters and part of your reproductive system and spleen adrenal cortex cardiovascular systems serous membranes connective tissue of the limbs so the bones I guess because it's lateral plate messenger because what's going to happen in your lateral plate mesoderm is that um and I don't have a good picture of it this is where your arm your limb buds are going to come from so your arms and legs are going to butt out of your lateral plate mesodermin form so all the the tendons and ligaments and bones and vasculature and everything that you have in your limbs is going to come from there um the Derm reactive tissue because of mesenchyme and then all of our internal steps because remember meso is Middle meso means middle so everything that's in the middle of you is going to come from mesoderm okay so in between your skin and your gut tube is going to be mesoderm and then connective tissues and musculature of the face okay all right so if we put it all together here it is all together so what do we have dermis of the skin epithelial lining of the blood vessels lymph vessels serous membranes muscle tissue connective tissue adrenal cortex heart kidneys ureter internal reproductive organs and spleen so internal reproductive organs means testes and ovaries and part of the ductwork but not all in the ductwork because some of the duct work like the prostate gland and the ureters are going to come from endoderm no not the ureters the urethra is going to come from endoderm the bladder I already say that all right so then we want to go to endoderm uh I'll hear your Los somites okay and then um let's see lateral plate mesoderm so your arms and legs are going to Bud out of that stuff there that's on the outside okay then endoderm so endoderm becomes the innermost tissue after transverse folding so after we make a tube out of view so everything that's tubed is going to have is going to come from endoderm so the the epithelium lining it so simple columnar epithelium of the GI tract the respiratory epithelium urinary epitheater and transitional epithelium reproductive tracts all of that tympanic cavity auditory tube actually the cool thing about auditory tube is that it comes from endodermin and it also comes from ectoderm on the outside and the two butt up against one another and then so these are the tubes these are the traps so let's take GI so for example stomach this is all implied in this GI tract so stomach small intestine large intestine oh esophagus okay so esophagus and then rectum anus okay so but there's some aren't there's some still some other things that are not part of the tube of your digestive system right like your liver your gallbladder pancreas tonsils thyroid parathyroid and thymus glands all those that can come off of this Center gut tube so these guys will Sprout off of your GI tract to become these glands and things okay these accessory organs then the cool thing is that here was you so this was your gut tube so this is your mouth and I I'm gonna probably make another video because I just realized it's the thing that I want to show you is not in here it's really really cool um it's not here so anyway dang it I'll make another video oh what are we missing I'll have to show you in a minute all right so here's your mouth here's your pharynx right okay so now you're gonna go into so you're esophagus it'll be your esophagus but what is right next to your esophagus friends your trachea so we're gonna take and we're gonna make a little oops I didn't mean to do that whole line but anyway so we're going to take a little we're gonna make a little opening right here and we're gonna make a trachea off of that in your pharynx and then we're going to grow lungs on the ends of your trachea I didn't draw that very good there we go okay um so that's where your respiratory tract epithelium comes from now let's go back to here because I don't know how that happened but we don't have a bladder so the bladder is right here oh okay let me tell you why so um epithelial lining respiratory tract GI tract urinary tract that's why they just included urinary tract it didn't take out bladder so urinary bladder is part of that urinary tract urinary bladder and urethra but your kidneys and your ureters are going to form from mesoderm and so they're going to come down and then they're going to plug in once your bladder gets made and your urethra then they'll come and plug in to the bladder okay so this stuff came so here you have an opening you have that cloaca you remember we've talked about cloaca before well maybe I haven't but anyway so your cloak is this is the one opening that links the urogenital and and digestive tracts all together so your urinary system your reproductive system and your your anus they're all together in one opening and so what we do with that opening is that we fold this in to make your bladder and then we seal it off so that it's not connected to your rectum and behind it or your vagina and your rectum depending on what sex you are all right um okay so let's make sure we know bladder and urethra are in here and reproduct reproductive tracts is going to be the vagina um and prostate gland and um but the rest of it's going to come from mesoderm so we kind of pair up so here in mesoder or okay kidneys reproductive system so these are going to be the gonads over his intestes and um vas deferens and um SEMO vesicle and then for females is going to be so Aubry though obviously the ovaries and the uterine tubes and the uterus okay and then we're gonna meet the vagina to come up come up and meet it and same with the seminal vesicles and vas deferens are going to come down and meet the prostate gland and the urethra all right probably more than you needed to know but anyway okay and then organogenesis is just making organ so by week eight week or the week eight upper and lower limbs I've started to take their adult shape because now what we're doing is taking that cartilage that they were made out of and start tournament into bone okay so by week eight we have formed the foundation of everything and now we're just going to grow it from here um and this time by week eight is very sensitive to teratogens substances that cause birth effects or death like we said Alcohol Tobacco drugs and viruses so we don't want to do anything during gastrulation say prior to week eight we have to be very very careful so that we are not exposing our baby to the teratogens and causing birth defects okay um let's see so like I said before eight weeks okay um peak development time is just different for different organs limbs four to eight weeks and then we would because they're forming collagenously and then they'll turn to Bone after eight weeks because they're all dead okay and then external genitalia late embryonic through early fetal period that's kind of later well no um yeah a little bit later so here is the thing teratogens are the most dangerous during the peak development of a particular system and since your nervous system is first and a cardiovascular system and skeletal system and reproductive system um it varies all right now if you notice this is from chapter 28 so this is this was in the reproductive system chapter but I prefer to teach it with the um embryology chapter so that's why it's here so this is what determines um phenotypic sex so what genes do you have and how does that turn you into physically a male or a female so you in order to be a male you have to have a y chromosome okay and so we have this region we have this Gene called the sry gene and in the sry gene on the chromosome is the testis-determining factor or tdf region and in there is the sry gene on the Y chromosome and a genetic male and if the sry gene is fine and is expressed then it's going to produce proteins to stimulate the androgens that are in the adrenal cortex and the testes okay so the androgens are then going to make you typically typical phenotypically male so elongate the penis develop the um that's different or the ductus deferens and the sum of s gold and all that kind of stuff now that Y chromosome is absent like you're a female or I don't know how else you're going to be if you have no Y chromosome unless you had a non-disjunction we don't get non-disjunction in males you can't be a male no you're just a female because you have One X chromosome so if you have if you're female put it that way or you lack so there may be mutation that causes you to lack or have an abnormal sry Gene no testosterone so we're going to put that because it's all about the testosterone test osterone it's all about the testosterone then you're going to still be phenotypically female but you could um still be an XY male but then because you weren't expressing testosterone then you would still stay on the female floor plan and so um uh uh anatomically you would you would be a female okay but yet you could still be a male because you could still have the Y chromosome if the gene had mutated and it wasn't even present or that you weren't making the testosterone like you should all right now um let's go to a picture all right so you start out at five to six weeks of development as sexually indifferent okay so we can't tell by looking at you whether you're going to be a male or a female and you have two sets of ductworks associated with what's going to end up being your kidney and what's going to end up being your gonet so this genital Ridge is either going to be if your X Y is going to turn into a the testes and if it's XX then it's going to turn into an ovary then we have the tubing so we're born with two no we're not born we we develop with two tubes mesonephric and paramesonephric now I'm not going to refer to them as that anymore so mesonephric I'm going to give them their people name the person that named them or that they were named after or named for so the mesonephric ducts are known as the mullerian nope are known as the wolfian Ducks okay so I'm gonna from now on call them Wolf the index these are for the boy these are going to develop into male ductwork right there okay then paramazonephric Al Netflix are going to develop in or called mullerian I hope I put the light on the right yeah I did mullerian ducks and those are going to develop into female ducks okay so how does that work so you're so at five to six weeks you have both kinds you have mesonephrine ducks and paramesonephroducts then testosterone would if you are a boy testosterone will start being secreted at about seven weeks and that seven week period is now going to start acting on the mesonephroducts and cause them to grow so what are they going to do they're going to become the efferent actuals they're going to become the epididymis they're going to produce the seminal vesicle and the ductus deference okay so all the two parts efferent actuals epididymis ductus deferens and seminal vesicle because it's gland that epithelium those are all going to be from the wolfian Ducks okay so the wolfian Ducks are going to progress now that testosterone is going to act on the testes as well and it's going to cause the spectacular cells to produce a substance called anti-mullerian hormone and that amh is then going to act on the mullerian ducts or the paramesonephric which are out here on the edges and we're going to inhibit their growth so that all you have by the time you're born are just oh geez Wolfie and ducks okay so wolfy and Ducks are going to be SEMO vesicle ductus deferens uh epididymis effectuals they're going to plug into the testes okay now what's going to happen if you're if you don't have any testosterone if you don't make any testosterone at all these mesonephric ducts are going to shrivel up and disappear and we will just keep growing the mullerian now genetically you are designed to just grow new larion ducts so if there's no testosterone to come in and change the mind of your cells then you just keep growing the ductwork of the mullerian ducts which will become the uterine tube then the uterine tubes are going to fuse together so yeah they're separate right here and right here and then they kind of meet right here well they're going to meet earlier and they're going to fuse together and make one big uterus and then they're going to plug into the vagina so your general assignment is forming the urethra in the vagina and the urinary bladder which came from endoderm so all of this yellow down here came from endoderm but the purple and pink came from mesoderm all right so girls get mullerian ducks that will um turn into the uterine tubes and the uterus and then the boys have Wolfie and ducks that will turn into these hair inducturals if your induction is epididymis ductus different seminal vesicles um and remember you what's the key if you want to be on this pathway right here then you have testosterone okay so if we go back here um so we have two duct systems we have mesonephric nail duct system and they Connect into the developing urinary bladder which came from endoderm okay then the pair of medicine females uterine tubes uterus Superior vagina and then they're outside of the mesonephrine that's why they're called para is because like parasympathetic remember is around your sympathetic so that's what Pera means all right and I don't know why I didn't get a pretty background and it didn't want to fix this so sorry all right so both deck systems are developed in human embryos but only one remains in the fetus depending on whether you have testosterone or not so the female will build the paramesonephric which are the mullerian now why did I pick female as mullerian and wolfian as male well that's what they were called but how does that help me remember is because females are mules and boys are wolves and females are stubborn and males are aggressive I don't know but that's how I just remember meals are stubborn girls are meals and boys are wolves all right and then so then we'll develop mesonephric as boys and then I went through that and then female development means I have no sry proteins I degenerate my mesonephroducts develop the paramesonephric um between weeks eight to twenty see that takes a long time our skeletal system is already formed by definitely by week 12 and um look at this can go all the way through week 20. so we get a uterus and a vagina and then two uterine tubes and then the year uh the endoderm so this is meso and then Endo Derm forms the inferior vagina bladder and urethra all right mail week seven sry Gene secreted influence the gonad to become a testis forms the sustentacular cells which make anti-mullerian hormone which inhibits the girl ducts paramazonefric which then degenerate so then wait weeks eat eight through twelve we make efferent ductules epididymis ductus ductus deferens seminal vesicle and jackets where you don't okay all right um and then prostate gland bubble erythropland are going to come from endoderm from they sprout off of the urethra and then gonad oh here's interesting so remember this is testes because we're talking about male development so the testes form inside of the abdomen and then they go down into the scrotum so they descend into the scrotum and what pulls them into this scrotum is this thing called the gubernet gubernaculum so the gubernaculum thin band connective tissue attached to each testis helps descend into the scrotum testes are passively pulled into the scrotum but we're not done until the ninth month so you got to make sure when you have a little baby that you feel you palpate the scrotum to see that there's a testis on each side all right and then so here you can get into this we just don't have time so I'm just leaving those things about when things don't work properly okay now what about the outside okay so male and female genitalia develop from the same primordial structure so we all have the same things in common and then again testy testosterone is going to come in excuse me and influence the progression of these structures so the first thing we have your general Folds so they're gonna surround when it's eventually going to be the urethra one way or another they are going to surround the urethra and in the female they're also going to surround the vagina okay General tubercle as a rounded structure anterior to the original fault that has erectile tissue in it okay I'm pinning that and then labial scrotal swellings well that kind of gives it away doesn't it so paired structures lateral to the urethral fold so they're just going to be on the outside I wonder what they could form into all right so until week 12 we they look identical whether you're a male or female because there's not enough testosterone to make differentiation but by week 20 we can tell them apart on an ultrasound and so that's why oh we wait until week 18 at least week 18 week 20 before we have a genetic not a genetic how we have a ultrasound um check to see what sucks your baby is okay now we can do it blood testing wise if we withdraw some blood that's baby blood on blood but baby blood but I wouldn't ever mess around with that so um just you know ultrasound or just wait and see what it is I guess it's up to you it's whatever you want all right so in the absence of testosterone female genitalia developed so whether you are a female you're XX female or if you're an XY male you could be making here's the thing oh excuse me you could be making testosterone but what if it doesn't bind to these structures then genetically you could be an XY male but you know typically your physical structure May manifest as a female so that's where we run into all sorts of problems all right but anyway so the genital tubercle is not going to do much of anything it's just going to be that little tiny cluster of erectile tissue in the female that's the clitoris the urogenital folds don't fuse they just become the labia minora remember I said they're outside of the urethra in the vagina so they're the folds that are immediately around those two openings then the labial scrotal swellings they just stay open become the labia majora so they're just going to surround all that external genitalia protect the vulva all right but what if testosterone is present what if you are female and you are producing excess testosterone because females do create testosterone but what if if there's a hypersecretion of that then that may influence the development of your external genitalia so again a problem all right so in the presence of testosterone the genital tubercle elongates and enlarges to form the end of the penis the glands of the penis and the dorsal side of the penis which is going to have the erectile tissue in so the uh Corpus spongiosum and the corpora Amorosa all right then the urogenital folds are going to fuse around the urethra and form the body of the penis so this is the end of the penis and then internally inside of the penis then that urogenital fold is going to fuse around the urethra now I'm going to show you a little picture about something that can happen which um it's kind of crazy when this urogenital folding thing doesn't happen correctly and then the year the labius girl swellings are going to come together and form the scrotum so let's go to what you look like as a baby here you are in week six genital tubercle labial scrotal swelling your genital fold doesn't matter this is every so we have the sexually different stage every male every female looks like this to begin with now what do we have no testosterone yeah I have a hard time spelling testosterone so look at the genital tubercle doesn't really change very much okay um labia minora they look just like the eurogenal folds labia majora look just like the labial squirrel swellings oh we're starting to develop a little bit something going on here development of the glands okay the end of the penis um we will have erectile tissue that's going to go down here into the penis as well look at what's happening to our urogenital fold it's starting to close up and look at where it closes up first so it starts down here and it's just like a zipper and it closes together and it zips up and it zips up and it zips up until finally it's totally closed over and the urethra is on the inside but I'm going to talk about something when that doesn't happen all right so now let's look at what happened as a as week 20 exterior genitalia well differentiated okay glands of the clitoris is actually receded and it's really not much of anything anymore um labionora Menorah there's the folds remember I said it's going to surround the urethral orifice and the vaginal orifice here's our labia majora not doing anything either State remaining open what do we have oh look this urethral orifice has now been drawn through and comes out the end of the penis comes out through the middle of the glands because what we did was zip up so this is this Ray fee that's right here on the back of the penis is actually the zipper for your virgin or your um yeah your urogenital fold so they zipped up and formed the body of the penis now here's something interesting sometimes if it doesn't zip up all the way you're going to get an opening right here is your urethral orifice instead of the outer there in the glands at the tip of the penis so if this happens and it's fairly common we call it hypospadias I think it's with an A so this is now this is where the male is going to urinate out of it's going to come out of the end of that instead of the end of the penis sometimes we have episode epic epispadius excuse me for me to say where the openings on the back of the P or the I don't know the other side of the penis however side you want to call that um it's actually the ventral side um and then you can urinate out the top of the penis but that's that's really rare hypospadias is the thing that's more common and then look at what the um uh labiosperidal swellings have done that hasn't completely they're gonna come all the way together and form a wall all the way together and so that's why there's a septum in the middle of the testes I mean in the middle of the scrotum for each testis to go into and so then the testes will be in here and in here all right okay so let's go back and wrap all of this up because we don't have a lot of stuff going on now um yeah let's just power through this last 10 minutes or so okay fetal period so after everything has developed now we're just going to make it big we're going to mature everything we're going to grow we're gonna lengthen um from a two and a half centimeter embryo to a 53 centimeter baby and then weight increase is most striking during the last 10 months last 10 months yeah I'm pregnant but 20 minutes the last two months all right pregnancies divided into three trimesters first trimester zygo becoming embryo and early fetus growth of fetus expansion of maternal tissues during the second trimester and the third trimester we're getting the fetus is growing the most rapidly and we're getting ready to deliver all right not gonna do any of this stuff I've left this in here for anybody that's interested I'm just going to click through these slides real quick so um hormonal changes not um I didn't put any of this in your notes um we do have um relaxed lips prolactin and um uh beginning and so that we can have lactation after birth we know about oxytocin um our uterus is getting bigger or mammary glands or developing here's what's happening in the mom and you can get more I mean warming morning sickness which I always have and all this gestational diabetes cardiovascular changes you get another two liters of blood in you and so your your blood pressure is going to go up and you're pumping around a whole lot more blood than um than you were before as a non-pregnant person so preeclampsia hypertension of the mother the plant placenta will end up with poor perfusion um bed rest medications labor induction but usually You Gotta Give rid of that baby out of there okay um what are people that might have pre-eclampsia previous preeclampsia or diabetes older age or obesity um and then eclampsia has high blood pressure causing seizures and that is absolutely a medical emergency when you have that um and then okay so now we want to go into labor so labor is when we get rid of the baby typically at 38 weeks full-term pregnancy remember I told you about the two weeks in the beginning um contractions can come and go if we have Labor before 38 weeks um premature we don't want that because baby's not ready baby's got to stay in there and cook all right so we can have contractions um in and around our pregnancy um called Braxton Hicks contractions really what is happening is that your your uterus will just tighten it'll just kind of get ready for um having a baby um relatively weak do not increase in intensity irregularly spaced don't become more frequent um doesn't lead to cervical changes so you're not going to dilate your or a face um I used to get Braxton Hicks well I always got Braxton Hicks but I was um right when I was going to deliver my oldest daughter um my kids would go oh you're having a contraction you know because my face would flush and it wasn't Braxton Hicks but it wasn't anyway okay so when we're in true labor this is when we're getting ready to have a baby so what are our uterine contractions are increasing in intensity and regularly and we're changing the cervix if you watch the having a baby video you'll see exactly what all of that uterine contraction is going to do to the cervix the hypothalamus is involved it's producing oxytocin the fetal fetus's hypothalamus is also producing octotism everybody's producing oxytocin let's get this baby out of here um okay so both we're gonna make prostaglandins which stimulate more uterine contractions and soften and dilate the cervix and the maternal and Fetal oxytocin initiates true labor and then we put you into positive feedback because contractions lead to more oxytocin more oxidants than leads to more contractions and we just keep going and going and going until finally you have the baby um let's see frequency intensity pain doesn't go away dilation and effacement happen and then there's all the positive feedback stuff um so the baby's head push against the cervix and stretch and dilate hypothalamus oxytocin more prostaglandins more intense keep going um prostaglandins are gone uterus is no longer stretched oxytocin drop sign labor ceases yay which I just have no idea because I've never been in labor all three of my kids were C-section and the first was an induction followed by an emergency C-section and the other two were just C-sections because we're just like you know what nothing works I'm I don't work okay and so this is everything that goes on and then here's inducing labor I was more than a week late and so they're like we gotta get that baby out of there so they induced me but then he wasn't progressing he wasn't doing anything his head wasn't down he wasn't causing me to a face and fit well that's the same thing dilate in a face I stayed out of three for 12 hours nothing was going on on Pitocin and nothing was happening okay all right um here different anesthesias remember my spinal block cesarean section did not numb all the way in it just numbed my skin so that when you pinched it I said no I don't feel it I don't feel it and then they made that first incision that's fine I didn't feel the cut with the scalpel but all the pulling and tugging and and cutting and everything after that I felt every ounce of that with my last child so I wasn't anesthetized deeply enough and um yeah so my anterior abdominal wall was not numbed all the way through and they had to put me under general anesthesia in order to finish off my c-section because my heart rate was racing I think if my heart rate hadn't done anything they might have just left me there good night I can't even imagine that I was in so much pain friends I couldn't even speak I couldn't even tell them that was what was wrong with me all I could do was cry and I think that crying is what elevated put me into that stress and elevated my heart rate and that's when the anesthesiologist said oh okay I'm putting her under and that was it I knew nothing more and I came out of came out of uh in recovery crying came out the anesthesia crying because I was crying as I went in and um had uh had no idea what had just happened didn't know I was had a baby or anything like that and they wheel me into my room and there's my husband holding my baby and I'm like what is that in his arms it was the weirdest feeling in the whole world it was so disconnected from everything that had just happened so there's my fun description of my last pregnancy or my last delivery my deliveries suck friends my my pregnancies are great well no because I'm I get hyperemesis but um but then after that when I'm in my second trimester then I loved being pregnant for that three months or five months it's just the deliveries just are crappy all right what do we have to do well if you watch the having a baby video we're gonna dilate so uterine contractions are going to cause the surface the surface the cervix to a face and dilate from nothing fingertip width to 10 centimeters which is if you put your thumb and index finger to make a circle out of your thumb and index finger of each hand that unless you have super big hands because mine are fairly decent size um that's 10 centimeters this is the longest of the three stages you could be in there for for hours and hours and hours and hours so it is the time it is the stage with the greatest variability in time um so people who have women who haven't had birth yet who knows eight to two we have no idea how long it's going to take you to dilate women who have given birth usually less time for the second baby all right so what's going on your baby's head my kids never ever were down in the birth canal never ever ever so I never went into labor I never dilated so annoying um I really wanted to have a vbac but uh it just wasn't gonna happen and so I had to have all three C-sections um rupture of amniotic sac and release of the fluid can help um manually rupture it if necessary that was the worst I uh it just was horrible so I I felt like the little scrapey thing tool that he was using was scrape in the back of my throat and so then one of my one of my so I had a nurse practitioner that I was talking to that's a good friend of mine about that and she goes oh yeah isn't it funny how your nerves all connect and do weird things when they go to your brain like yeah yeah all right so here we are early dilation late dilation see your baby can just squeeze through that spot right here we're not gonna squeeze through a three but we're gonna squeeze through a ten um and then expulsion stage usually 30 minutes or several hours we don't even know um uterine contractions will help push but then facilitate the if the woman Bears down um use the valsava maneuver to increase abdominal pressure if you want yes whatever the crowning of the baby's head stretches the vagina um we hardly ever do episiotomies anymore um um muscle surgically in size we just don't do that because it just takes so much longer to heal um yeah sure it creates a wider opening but you just cut through the muscle uh no tear because you're going to tear where you're supposed to tear that's the rule and then umbilical cord cleansed off it tied off and then here you're having the baby and placental stage is when we get the um after birth out so the placenta and all the rest of the step so we're still we still got to deliver that okay people don't really think about that so there's the placenta all right last but not least friends we have something called the apgar score so once you have your baby we are going to evaluate your neonate at one minute and five minutes after birth and we use five signs so we look at heart rate respiratory um muscle tone reflex irritability and color um so we and we evaluated on a zero to two scale so you can get a 10. that's a perfect apgar score so if we look at this chart absent less than over so um one minute ten minutes so you can see it our feet five minutes here you can see a six we want to get to it excuse me a ten by five minutes so when my son was born I have no idea what his heart rate was respiratory rate he was Zero hits no respiration um he was purple so that goes with the pale um so two four six that's the best that he could get but I he wasn't crying so that was a zero on that so what maybe his heart rate was high enough to three whoa my son had a three so and I don't know what he was at five well at five he was more up here because he was crying he was breathing and and could cry and he was pink and everything um even his extreme he might have even had a one on there because his extremities were still blue at that point we can put Blue in here because you know what a purple because he was totally purple when he came out and he wasn't breathing at all and so they had him on the table and they were bagging him and his dad and I were going come on buddy come on Cameron you got to breathe you got to breathe and he wasn't and then all of a sudden he started to breathe and just to watch his skin become oxygenated he just went his from the top of his head you could just see a line that just went down his body and he turned pink and his his hands and feet were still blue his arms were a little Pinker but oh just to watch that line pass down his body it was amazing all right and um that's it hey oh I was gonna tell you let me just tell you really quick so because he had such a low apgar score to at Birth um I got a call after after you've been home for a couple weeks and I got a call from the health department in Utah and uh where we were living and they said hey we're just checking on your baby see how you guys are doing and I said well yeah he's great he's fine and um uh they said okay we're glad to hear it and then that was it and I thought that's weird until I was teaching this and I was like oh that makes sense all right so here is just a little bit last stuff um you can read through this we're just not even gonna do any of this um I probably uh well no we did it so let's go back over here let's go back the changes in the neonate okay so yeah let's look at I didn't put the notes in here but we talked about it in lab so um make sure that you know this so um feed alone is obviously not fully inflated prior to birth takes a breath within 10 seconds caused by central nervous system reactions to change environment lungs inflated with first breasts or fact it keeps the alveoli open if the you're born before 28 weeks you don't have enough surfactant so you may need to be on a ventilator until your lungs can mature because your lungs are not fully matured until you're eight years old and so and your lungs go from being very thick dense tissue to the to the air sponges that they are as adults and um and so that has to develop over time and so you don't want to be born too early now circulatory so remember circulatory we had the ductus arteriosus the foraminal Valley the ductus fenosis we went over in in the lab portion um okay and then pressure is going to decrease on the right because the right side of the heart was the side that was pumping the blood out to the rest of the body because it was going through the ductus arteriosus but then when we take the the um first breath then the pressure becomes greater on the left side of the heart and because we're breathing and we want more blood and pulmonary arteries and Pulmonary resistance drops and more blood comes over here on the left and then the left pumps the blood out okay that's where we're going to end it so yay okay all right friends so that's it um what a journey you've been on uh good luck with everything with this test and then your final exam and let me know if there's anything I can do for you otherwise you got no more videos to watch okay thanks bye