 Hey everybody Dr. O here. This is probably the most important video when you're dealing with the femur reductor system because it shows the complex interrelationship between all the hormones involved and then also how critical timing is when it comes to the ovarian and uterine cycle. So very very important. So first thing we're going to show here is just the fact that we've had to make the follicle. Remember the follicle is going to be where the oocyte the female gamete is stored but the follicle will also become a temporary endocrine organ in just a moment. So you'll see that follicles develop the process is called folliculogenesis we covered in a separate video. Many of these follicles will develop but one's going to win. So we're just we're just starting with the fact that we have one perfect single tertiary follicle and then now we're going to jump in here. So it's just going to go down we're so it won't go in order here but I just want to talk about how all these are related timing critically important. So the ovarian cycle you see during the follicular phase of development first the ketoneur member is it's dominated by estrogen so that's the first important thing to note they're the first half of the ovarian cycle is dominated by estrogen then we have the luteal phase the second half is dominated by progesterone so that during the follicular phase the follicle is developing so this follicle is preparing to release a fully functional egg and that's what's going to be happening during the follicular phase pretty good name for it right then we have ovulation the key thing to note here in the middle with ovulation is they spike in luteinizing hormone these it's called the lh surge or luteinizing hormone surge is what leads to ovulation so as so it's like switches gears so the follicular phase of the ovarian cycle is dominated by estrogen then lutein this huge spike in luteinizing hormone leads to ovulation but also leads to what's called luteinization which is why the second half is called the luteal phase which is now dominated by progesterone so very important things there follicular phase dominated by estrogen ovulation occurs because of a huge spike or surge in luteinizing hormone the luteal phase dominated by progesterone so we see so the follicle has been released from the ovary and ovulation is called the oocyte to be released there you see the corpus luteum remember the corpus luteum is a temporary endocrine structure it takes the theca and granulosa cells from this this beautiful follicle and it and it turns into a factory making the female sex hormones especially progesterone as long as the corpus luteum is around progesterone levels will stay elevated 10 to 12 days later though if this egg has not been fertilized the corpus luteum will break down and become the corpus albicans going from being yellowish to whitish and then it'll be degraded which will which will signal to the body that there's not going to be a pregnancy this month and that's why we're going to see these changes later so that's the the phases of the ovarian cycle then we have the menstrual cycle so timing along with it and while this month's follicle is developing we have menses during the the uterine cycle last month's uterine lining is being sloughed off because there wasn't a pregnancy last month or else we wouldn't be making a new follicle this month so last month's uterine lining is sloughed off so we can grow a new one so menses or the loss of last month's functional layer of the uterus is the start of the uterine cycle or the menstrual cycle that's menses the proliferative phase is also under the control of estrogen so as long as we're in this environment full of estrogen the the new functional layer for this month's uterine lining will start to develop and thicken then you see at ovulation as we switch to a progesterone dominated system now we're going to see what's called the secretory phase of the uterine cycle so the uterine lining gets thicker and thicker it starts to produce thick glangular secretions releases food for hoping that this fertilized egg comes along right so if that oocyte was fertilized it'll happen somewhere in the uterine tube and probably right near the middle and then it's going to be a zygote and then two cells and four cells and eight cells if this cluster of cells reaches this uterine lining then it's going to be nice and thick and inviting it's going to be sticky enough to grab it and it's going to have the food to feed it that's why the two cycles have to be timed together you can have the perfect egg but no uterine lining for it you can have the perfect uterine lining but but no egg so the timing and the connection of the ovarian and uterine cycles are very very important so if there's pregnancy the secretory phase so the the progesterone levels will stay elevated from signals from your body and you'll continue to feed this embryo and into the fetus if not there's no reason to keep this month's uterine lining along around so the drop in sex hormones especially progesterone will cause the the functional layer to slough off and then we're back at the beginning we're menstruating last month's uterine lining off while producing the next follicle for the for the next ovulation oh looking at the hormones you see the pituitary hormone levels the key thing to note there is just that the follicle stimulating hormone is is elevated higher than luteinizing hormone in the first half which is why it's called follicle stimulating hormone and why it's the follicular phase the huge spike in luteinizing hormone is what leads to ovulation and then we have the switching we're now luteinizing hormones going to primarily be elevated and progesterone is going to be dominant the ovarian hormones there you see that again during the follicular phase estrogen is going to be dominant you see it really start to climb once this one dominant follicle is taken over and then then it flip-flops the second half of the ovarian cycle and and uterine cycle dominated by progesterone so we talked about menses that would that's generally a process that takes somewhere between two and seven days but the cycles are if everything's working perfectly the cycle should take 28 days total and i think i've covered all that the last thing to note here what else should we say the temperature stuff that's pretty cool so if you're if you're trying to figure out when you ovulate you can look at the you can keep a calendar and look at look at the length of menstrual cycles and these types of things but one other way you can do it is to monitor your core body temperature because these fluctuations and hormones will change your core body temperature so during the follicular phase the first half here when estrogen is dominant your resting body temperature is going to be about half a degree maybe 0.3 degrees celsius about half degree fahrenheit lower than in the luteal phase so the so the first half of the so when you when then you're going to see the during ovulation the body temperature is going to drop and then it's going to be to climb so you're going to see an even more noticeable climb so you're going to see a lower temperature in the in the follicular phase of the ovarian cycle you're going to see it drop during ovulation and then it's going to peak which that elevation and temperature is going to be even more noticeable so if you if you keep a calendar and you're doing this you can actually predict when you when you ovulate based on core body temperature that's pretty cool Okay, so that's that. We've covered the oberian cycle and all the things happening there. We've covered the uterine cycle and the hormones involved. The last thing to just one last reminder, if there's a pregnancy, then these hormone levels are going to stay elevated and you're not going to slough off the uterus and also you're not going to make another follicle for next month. There's no reason to because you're already pregnant. If there is not a pregnancy, then you'll slough off the functional layer of the uterus and you'll get ready to start again and try again next month. So that is very important. I'd watch this video a few times, the interplay between the oberian cycle and the uterine cycle and all the hormones involved. I hope this helps. Have a wonderful day. Be blessed.