that lining remember in the endometrium we have two different layers to the endometrium in red here i'll put the stratum functionalis and that's what grows each month and then deep to that is going to be the stratum basalis and that's what it grows from so the stratum functionalis gets bigger each month and then if pregnancy doesn't occur it slops off deep to it is that stratum basalis the basal layer and that is going to help the oops you can't see it yeah it's erasing it that is going to yeah there you can see it strong basalis is going to allow that new layer to grow each month okay and then when if the embryo does not produce human chorionic gonadotropin and feed back and tell that corpus luteum to continue to produce progesterone that inner layer is going to slough off and then then it will start to after it all is removed the tissue as well as the blood that goes with it because remember we have in here we have those spiral arteries and when progesterone levels go down it causes those spiral arteries to constrict and when they constrict it starves that tissue for blood for nutrients for oxygen it starves it and so that tissue is going to slough off it's going to die and then peel off and when it does it's going to break those blood vessels and you're going to produce blood as well as um you're going to have tissue that stratum functionalis is also going to be shed so once it starts feeding back it keeps the progesterone levels high as long as progesterone levels are high then that stratum functionalis will remain as long as it remains implantation can occur now i think i told you before that of all the embryos that are formed that reach this stage two-thirds of them don't implant and those that do implant thirty percent of them won't survive so you know when you consider how many people get pregnant and how easy it seems for most younger people in particular to get pregnant and think about how many of these that could occur that you might not even know about where you were pregnant um but it didn't take and you never knew you were even pregnant okay because most of us aren't taking pregnancy tests all the time um so there's a window of time during which implantation can occur things have to be just right and the levels of hormones progesterone in particular but also estrogen have to be what they're supposed to be and if they are then this guy i'm actually just going to draw the stratum functionalist like that this guy the trophoblast is going to release digestive enzymes that are going to eat through the that stratum functionalis so that it can actually it's going to move inside of it and be completely encompassed inside of the stratum functionalis it digests its way in and now what's going to happen is it is going to start further development is you're gonna have a yolk sac and um we can look at that i this is well beyond my level of uh drawing ability so um there is a yolk sac and it's going to develop the corion remember the chorionic villi help this is over here we're going to have th the trophoblast is going to become the embryonic contribution to the placenta and then the mother's contribution from the placenta is going to come from that endometrium okay so um we can move into pictures now um and and then we can talk let me just quickly go through um some of the other hormones and then we can go to to the powerpoints and look at some actual pictures okay so let me just make a little chart for you so here we can put hormone an action okay estrogen action secondary secondary sex characteristics so it's it's slim hit rounded hips excuse me the um less body hair less muscle mass also provides helps with regulating cholesterol levels in your blood so women tend not to have problems with cholesterol at least until they go through menopause okay so it's involved in secondary sex characteristics also development of the egg and the endometrium plays a role in that as well um progesterone stimulates ovulation oh no i'm sorry what am i saying that's a luteinizing hormone progesterone um helps maintain the uterine or endometrium and when you have a decrease in progesterone it causes menstruation um progesterone is also involved in milk production and remember that when we talk about labor when progesterone levels are you need to have the estrogen levels um exceed the progesterone levels in order to start labor okay and we'll look at the slides for that um because i think it will make more sense that way glutenizing hormone is going to stimulate ovulation follicle stimulating hormone is going to stimulate maturation of follicle and the oocyte um uh human chorionic gonadotropin is released by the embryo and remember that the corpus luteum is going to keep on pumping out progesterone until the placenta takes over and then human chorionic gonadotropin levels will decline keeps corpus luteum making hormones relaxin relaxes uterine wall for implantation and pubic symphysis to spread the hips later in pregnancy inhibin inhibits in particular fsh just like it did with the guys it inhibited fsh although in this case with guys it inhibited fsh and that prevented them from producing too much sperm from wasting valuable resources on making more sperm than what's needed for women it prevents you from getting pregnant when you're pregnant so inhibit is going to inhibit follicle stimulating hormone so the follicles don't develop when you're pregnant and then i also want to put in prolactin really small prolactin is involved in producing milk along with progesterone garlactin on its own won't make milk you have to have progesterone with it so for lactin plus progesterone produces milk um and then the other one geez we're just sticking maybe up in here oxytocin oxytocin labor contractions and milk ejection it's also called letdown of milk so proloxide and progesterone help us produce milk the oxytocin allows it to be expressed from the breast okay allows it to be moved out when the baby suckles and oxytocin and prolactin are both positive feedback all the rest are negative okay um so this is it's a whole lot of hormones in the list estrogen progesterone luteinizing hormone follicle stimulating hormone human chorionic anatotropin relaxin inhibin prolactin so that's a whole bunch all right any questions about these hormones okay so let's go to the power points and um i think what i'll do is uh go to oh well i got a wild haircut going on today um me share my screen and i think what i'm going to do first is go into that chapter 29 and finish that whole fertilization everything finish that and then move to back to 28 and go over more about the female reproductive system okay okay so do this is the wrong one i chose the wrong one stop share and there we go okay so um remember that the gestation is fertilization to birth so it's about 38 weeks it can go longer sometimes it goes shorter the only the first two months of it the first eight weeks are the embryonic period and remember that is a crucial crucial period because development of all of the organs occurs during that period once that period passes all you have then following that is growth of already existing organs