Menstrual Cycle (Nursing)

00:00 Well let's go through the menstrual cycle. First, the follicle ripens. Then 1 ripe follicle ruptures and the egg is released. When the ruptured follicle then turns into the corpus luteum. See this to me is so cool because like nothing is wasted. Right? You've got a follicle, it ripens. It lets go of the egg and then that just doesn't disappear, turns into something useful. That ruptured follicle turns into a corpus luteum. I think it's awesome. You talk about recycling. That corpus luteum will atrophy if pregnancy doesn't occur. So then it will go away but if pregnancy occurs, this is going to cause some extra changes in the uterus. If it doesn't happen, hormone levels will drop when the corpus luteum atrophies in the uterine lining sheds. So, that's just a monthly cycle. The follicle ripens, it releases an egg, then that ruptured follicle turns into the corpus luteum and if a pregnancy doesn't happen that corpus luteum will atrophy, that' when it stops, it kind of dies away, and so the hormone levels will drop when it atrophies and that's what causes the uterine lining to shed. Ta-da, you're welcome. That's your monthly menstrual cycle, kind of in a nutshell right there. Now, I love the drawing we have for you here of this ovary. It's kind of intense looking but it does a really good job helping you understand what we just talked about.

01:26 Now look, it's not important that you memorize all those different names but it let you sees are these primordial follicle, then a primary follicle, then you got the oocyte. Remember what that is. Write in your notes what you remember an oocyte to be. Right. It's an immature egg then it goes into the secondary follicle, in the Graafian follicle. This is the 1st half of the menstrual cycle. Now what hormone is rising during this 1st half of the cycle? Right, estradiol. Okay. So the estrogens are produced by the maturing follicles. So don't rush over this. Look at that maturing follicle from the primordial follicle, follow it all the way around to the Graafian follicle. I want you to write in your own words so you remember that this is where estrogen or estradiol is being produced. Those are the guys that are doing it. Now the 2nd half of the menstrual cycle, now we mark that 2nd half and 1st half by ovulation. So see the egg, shooting out there. So, now there comes the corpus luteum. So the egg has already shut out, we've already ovulated. Now it's going to start developing into the corpus luteum. So, look at that drawing there. You see the egg leaving, the blue arrow, the ovum. Now you got the corpus luteum developing and then you see the corpus luteum there. It develops in that ruptured follicle after the egg has been released and now that's what can start secreting hormones like progesterone and estrogen but more progesterone and that's what maintains the uterine lining. If pregnancy doesn't occur, look at what they have, actually the corpus luteum. It kinds of all shrunk out there to tell you that it atrophies. So this is the 2nd half of the cycle, the luteal phase. Now, after the corpus luteum dies and degenerates, we call it the corpus albicans if a pregnancy doesn't develop. Now in the luteal phase, the 2nd half of that cycle, when it degenerates, estrogen and progesterone levels will drop and that's what causes the uterus lining to shed. Now they gave you a pretty good picture there. You can see the uterus there and you can see the lining starting to drip down and become menstrual fluid. So, this has started when the corpus luteum atrophies or becomes the corpus albicans when pregnancy doesn't occur and then that's what causes the lining because of that hormone change. That's what causes the lining to start to shed.