Alright Ninja Nerds, in this video we're going to continue our discussion about the female reproductive cycle. If you guys haven't already seen it, go and watch the ovulatory cycle first because it's completely dependent upon being able to do this video. Alright, so now if you guys remember we left off with progesterone production right from the corpus luteum and then we had estrogen production also. So let's bring estrogen over here so we can have them together.
So over here you're going to have estrogen. and progesterone. Now before we actually go into what these hormones are going to do to the uterus, let's map out the three phases of the menstrual cycle. Okay so the three phases in order.
First one is going to be menstruation. Now the menstruation phase is the shedding phase. We'll actually put a little thing here to kind of describe it. So this is the shedding phase.
What do I mean by shedding? Okay, in here in the uterus, you have an inner lining. So there's an inner lining of the uterus which is called the endometrium.
Okay, so again, what are the two layers here? There's actually the specific layer is called the endo. Now the endometrium is actually composed of two like sub layers or strata if you will.
You see this like lime green one right there? That lime green one is actually called the stratum functionalis. Okay so this green one right here is actually called the stratum functionalis.
Okay it's that green layer right there. This blue layer below it is actually called the stratum basalis. Okay?
So, one more time. Endometrium is the inner lining of the uterus, which is made up of simple columnar epithelial tissue. And it consists of two different sublayers. One is the stratum functionalis, which is this green lime layer right there. And then the other one is the stratum basalis, which is this actual blue layer here.
During menstruation, the stratum functionalis is the one that gets shed out of the uterus. So what is actually being shed out of the uterine lining? It's actually going to be the stratum functionalis that's being shed. Okay, now about how long is the menstruation period?
Now again, assuming that it's an average, that average is about days 1 to 5. Obviously, it could change. from person to person, right, depending upon whether they have that actual menstruation period or whether they have heavy menstruation, you know, menorrhagia. Okay. Now, days one through five is the period in time in which this actual stratum functionalis is being shed. Let's show that then.
So what also is being broken down? Oh, before I do that, let's actually discuss something really quick. You see the stratum basalis right there?
You see that red artery that's going through it? That's a straight artery. Then the one in the stratum functionalis is actually going to be spirally and coily arteries.
Let's write that down right now so that you guys have that in your mind. So the stratum functionalis is really, really important. It has these things called the spiral and coiled arteries. Okay, I know it might seem insignificant, but it is extremely important that we understand this and differentiate that.
In the stratum basalis, it consists of straight arteries. Now specifically, these are branches of the uterine artery, which comes off the internal iliac artery. So these spiral and corneal arteries and these straight arteries are going to be arteries that are coming off of the uterine artery, which is a branch of the internal iliac artery.
iliac artery. Now, whenever the stratum functionalis is being shed, what are you actually losing with it? The spirally and coiled arteries. That's why there's blood being lost. So not only is there tissue loss, there's also going to be blood loss and that blood that you're losing is the vessels those spiraling coily arteries but what are you keeping those straight arteries which are within the stratum basalis okay that's the first step so that's our menstruation phase and what was the menstruation is consisting of specifically the shedding of the stratum functionalis with the blood that's carried by the spiral and coily arteries cool now what did you see that actually remains here the stratum basalis remains.
So this next phase is actually called the proliferative phase. Now the proliferative phase is actually going to be whenever you're regenerating your actual stratum functionalis of the endometrium. So the proliferative phase you actually regenerate your stratum functionalis layer. So you shed it off in the menstruation phase and then you regenerate it within the proliferative phase.
Another thing that you're going to regenerate is you're going to regenerate these spirally and coily arteries. So you're going to regenerate the spiraled and coiled and I'm going to explain how this happens. Okay, so first off, what days is the proliferative phase actually occurring from? It's occurring approximately from about days 6 to 14. If we come back over here for a second to the actual follicular phase, do you guys remember what days were the follicular phase? Days 1 through 14. And what was the primary hormone working in that area?
FSH, right? What was the primary hormone being produced? estrogen.
So now let's go ahead and see what this estrogen that we produced over here, what it's actually doing in the uterus. Well, I already told you what it's doing. It's regenerating the stratum functionalis. So let's show that.
What is it going to regenerate here? It's going to regenerate the stratum functionalis. That's why they call it the proliferative phase because it's going to cause proliferation, right, of the endometrium.
All right, specifically the stratum functionalis. What else did I say it was going to do? It was going to regenerate regenerate those spirally and coily arteries. What is that called whenever you actually make new arteries?
You know that's called angiogenesis? It's kind of a long-term auto-regulation, but this is where you're making these new spirally and coily arteries. And again, who's doing this?
This is actually going to be the job of estrogen. Now, you know what else estrogen is doing? Not only is this regenerating the stratum functionalis, not only is it regenerating the spirally and coily arteries. But you know there's also uterine glands that we have to have, these little uterine glands that are secreting specific fluids. He's starting the process of making these uterine glands.
And these uterine glands are going to be really important in the next phase that we talk about. But again, what is it doing? It's leading to the starting the production of these uterine glands.
They're not secreting anything. They're just making these uterine glands. So what's the next thing that they also do up here?
So not only was it regenerating the stratum functionalis and the spiraling corneal arteries, but it was also making uterine glands. Look what else it does. It's also really smart too.
You know here, this is the cervix of your uterus. There's specific glands within the cervix of the uterus. You know these glands, these actually are like mucus glands?
Look what estrogen does. these glands. It tells these glands to start producing a mucus, but this mucus that it produces is very thin.
So this brown stuff that I'm drawing here, this is a mucus, but this mucus is very, very... thin mucus. Why is it important to have a thin mucus? Because what happens around day 14 to about day 14 or 15, the female actually undergoes what's called ovulation, right?
And ejects that oocyte out into the ampullo fallopian tubes. If sperms, if someone's little swimmer decides to run up through this actual female reproductive tract, do you want it to be blocked by a thick mucus plug? No, you do not. You want it to be nice and thin.
And if it's thin, it's going to be easier for it to actually move towards the actual egg. So not only do you want it to be thin, but you also want it to consist of very specific chemicals that we talked about in fertilization that helps with called capacitation of the sperm. So what is it doing here to the cervical mucus production?
It's making it thin. So what is estrogen doing here also? It's also causing thin cervical mucus production.
For what? So that it's easier for the sperm to move up to the egg. And? It also contains chemicals that help with help in the Capacitation of the sperm activating the sperm helping it to clean its head right of cholesterol and glycoproteins and different types of things like that Okay, that's what's happening within this proliferative phase, which is around day 6 through 14 Okay, and again, what is it doing just to recap again?
It's causing proliferation of the actual stratum functionalis of The endometrium it's helping the actual angiogenic effect to make more spirally and coily arteries it's leading to the production of these actual uterine glands they're not secreting anything just undergoing the production of them and on top of that it's making a thin cervical mucus that the sperm cells it's easier to be able to get to the egg and helps to activate the egg right I'm sorry activate the sperm okay for capacitation now we go into the next part Over here. What was that last phase? So this last phase here is actually called the secretory phase.
Now, what was the primary hormone that was involved in the proliferative phase? Just so that we can continuously recap on that. What was the primary hormone? Astrogen, right? He was the primary hormone that was stimulating the proliferative phase.
What's the primary hormone do you think that's going to be stimulating the secretory phase? Progesterone. Now who was actually synthesizing and secreting that progesterone?
Let's come back. Remember in the ovary we had the luteinizing hormone convert the graphene follicle into the corpus luteum and then it stimulated the corpus luteum to pick progesterone? That progesterone right there that was produced by the corpus luteum is going to act on the uterus what is it going to do here in the actual uterus it's going to do some of the similar effects to what estrogen did what did estrogen do he caused regeneration the strata functionality right well guess what progesterone does he makes the actual stratum functionalis even a little bit thicker so he makes it a little bit thicker and then on top of that you're gonna have to have blood supply that part of the area right there right so what is it gonna do to this area it's gonna help to make the spiraling corley arteries a little bit longer right so it's gonna make more spirally and corley arteries guess what else is gonna do you know how those uterine glands were synthesized and they were made guess what the progesterone is gonna do progesterone is actually going to stimulate these uterine glands to start producing a nice type of fluid, nutrient rich broth. I know it's a heck of a nasty word to say, but that's what it's doing.
It's secreting a nice nutrient rich broth, which is rich in glycogen, which is a polysaccharide, a polymer of glucose, a lot of lipids. And a lot of specific types of proteins. So again, if we look at everything it's doing here, let's map out what progesterone is doing again.
The first thing he's doing is proliferating again. proliferating, the stratum functionalis, so making it a little bit thicker. What else is he doing? Angiogenesis, right, making those spirally and coily arteries even bigger, right, more of them.
And it's also causing the secretion of the uterine glands within the endometrium. But it's not done at that. He has to do something else. Estrogen was causing these cervical glands to produce a thin cervical mucus but you know if hypothetically if a sperm that this little swimmer would have got up there and fertilize that egg if it fertilizes it around day 14 technically we should have at least some type of blastocyst that's actually going to be implanting into the actual uterine wall, hypothetically.
That's not always the case, right? But let's assume that there is an embryo implanted into the uterine wall. Do you want anything to just have free access up into this uterus?
No, you do not. So what does this actual progesterone do? It switches the cervical mucus production by these cervical glands and look what happens to it. He plugs this sucker up. He forms a thick, thick, thick cervical mucus that plugs up the cervix.
Why? Why do you want to do that? Because you want to keep this area private. You don't want to have anything have access up.
into this area. So you form a thick cervical mucus plug to prevent any type of substances or any type of organisms up into this area to protect the actual potential embryo. So what's the last thing that it does?
It also causes a thick cervical plug to be formed. Okay, now, We're at the last part, right? And what was the secretory phase?
So we said that specifically for the actual proliferative it was day 6 through 14. On average, the secretory phase is approximately days 15... to 28. Now everyone you must realize that this is not always the case. Obviously menstrual cycles change from month to month all the time for certain people. Okay on average if I was give you like the average generally we say that about 28 days is like the normal range anything that's actually 21 or below so anything less than 21 is pathological okay anything that's actually greater than 40 is also pathological So on average we like to say that the average menstrual cycle is 28 days with give or take a few to 21 is the lowest anything below that is pathological and to about 40 is the top point that you want to go. One more thing if this female is fertilized right the embryo will implant into the wall of the uterus and it'll start producing specific types of chemicals.
One of those chemicals is called human chorionic gonadotropin. And what human chorionic gonadotropin does, it helps to be able to continuously stimulate the corpus luteum to make progesterone, right? So, if the female is not fertilized, so if she doesn't have fertilization, if the embryo isn't producing those chemicals, like human chorionic gonadotropin to let the corpus luteum know that he can start producing progesterone, right? Until the placenta develops around the 12th week, right, of gestation.
If he doesn't get those signals from the embryo, Can the corpus luteum produce progesterone? No. So what happens is, let's say that this egg over here is waiting for the sperm, and it gets to about, you know, day 26, 27, 28, and there's no fertilization occurring.
No fertilization occurring means no embryos implanting. No embryo implanting means no human chorionic gonadotropin. No human chorionic gonadotropin causes the corpus luteum to not produce progesterone.
Why is that significant? You know these spirally and coily arteries? Let's say I zoom in on one. Let's say here I have my spirulina coralea artery.
Its activity, so its activity, its normal vasoconstriction and vasodilation activities is completely dependent upon the stable levels of progesterone. So progesterone is keeping the normal contraction and relaxation of these blood vessels. It's keeping it normal. But what happens if there's no fertilization occurring? progesterone levels start decreasing.
Can they regulate the contraction and relaxation of these vessels now? No. So what starts happening as a result? If you don't have this progesterone, these vessels start undergoing spasms where they undergo very, very vasoconstrictive, vasorelaxation, vasoconstriction, vasodilation, so much that over time these vessels become very, very weak and their walls become very, very fragile. That what happens is eventually after one strong vasoconstriction, The blood vessels dilate so much that so much blood rushes into this area that the capillaries in this area rupture.
If the blood ruptures in this area, what starts happening? So let's say that these vessels here rupture. What starts happening then?
This blood. starts accumulating in the stratum functionalis, right? Because these spirulinae coralea arteries have ruptured.
So let's say here's some blood accumulates here also. And then what else? Over here too, right? These spirulinae coralea arteries also ruptured. If these guys are rupturing, can the actual oxygen and nutrients be delivered to these actual stratum functionalis cells?
No. If the nutrients and oxygen aren't delivered to these stratum functionalis, cells they become what's called ischemic you know what ischemia means ischemic means it's not getting enough oxygen supply to that area if they become a scheming eventually they don't get enough oxygen to where they become necrotic in other words they die if these tissue cells start dying what happens they start sloughing off it's a heck of a word I'm sorry for the word but it's what it is it's sloughing these actual layers off and what is it sloughing off It's sloughing off this actual stratum functionalis and the blood from the ruptured spirally and corally arteries. And whenever it's lost out through the actual vaginal canal, because what happens is eventually the progesterone production stops, right? So what happens to the cervical plug?
It goes away, right? That's another result of it. And look what happens here.
Look what you lose as a result coming out of the vaginal canal. You're actually going to have, what is this? This is the stratum functionalis. what else is going to be a part of that shrouding functionals all that blood that was lost from the spirulina core the arteries what is this called whenever you're shedding the inner lining of the actual uterus menstruation so now guess what happened the normal menstrual cycle ended at day 28 if fertilization didn't occur and it starts back over on day one to begin the menstruation process all over again now like I said if fertilization does occur then the corpus luteum continues to act like the hormone producing structure for progesterone until the placenta develops around the 12th week and then it actually dies off. If the corpus luteum doesn't, I mean if the fertilization doesn't occur, then the corpus luteum doesn't get those signals from the embryo.
Guess what happens to the corpus luteum? The corpus luteum starts dying and actually starts becoming scar tissue. So he starts dying and look what happens to it.
It starts turning into a nice scar and fibrous tissue. Scar and fibrous fatty tissue. What is this scarred and fatty fibrous tissue here called?
This structure right here is called the corpus albicans. So it's called the corpus. Albicans. And the corpus albicans is again the result of fertilization not occurring and the corpus luteum starts dying because it doesn't get signals from the LH or from the human chorionic anatotropin and what happens? It starts undergoing death.
and gets converted into fibrous tissue. What is that fibrous scar tissue called? The corpus albicans.
Okay and can this thing produce progesterone? Can it respond to LH? No. So then the actual whole ovulatory cycle has to start from the beginning. also.
Alright Ninja Nerds, in this video we covered a lot of information about the female reproductive cycle. I really hope you guys enjoyed it. I hope it made sense guys.
What we're gonna do in the next video is we're gonna do a nice little overview of everything here just to get a quick recap and make sure that you guys truly understand all of this.