now that we've looked at the female anatomy for the reproductive system let's look at how it functions we looked at how the male reproductive system functions and it's pretty straightforward pretty even Keel however when we start looking at the female reproductive system it's going to be much more complex the process by which the gamt are made is called oogenesis and so we say that the gamt is an oite or an ovam now with the male we notice that the gametes are produced at puberty however with females the gamate production is going to begin before they are even born then we're going to see that this process is going to become arrested or sort of dormant for a while until puberty and then the process is going to become active again and in the males we saw that gamt production of the sperm continues well into older age into their 70s in the females we see that the gamet production is going to have a limited time period and it will cease at a given time that is going to be referred to as menopause so when this female baby is Born the ovaries are going to have millions of these gamt the gametes are called o sites and they are at this stage what we call primary o sites now even before the baby is born during in utero there are even more of these o Ides but not all of them are going to be viable and sustained even to the point of of birth so there be natural degeneration of many of these potential gametes and this process is called at treia and we'll see this at treia occur throughout every cycle for the female when the oos sites are present in the primary oite phase when the baby is born that female baby is born they have begun the first phase of meiosis but they don't complete meiosis 1 they're going to be suspended or arrested in meiosis one so the process of O Genesis is going to produce that ovam as we mentioned and we commonly refer to that as the egg the stem cell is referred to as the oogonia so similar to the spermatogonia that we looked at for the male we mentioned that the female baby is born with the primary o sites and these primary o sites have begun meiosis 1 but they did not complete that phase when the female reaches puberty and hormones are starting to be released this process will become active again in the female reproductive system we're going to find that there are two cycles involved one of these Cycles is going to be the cycle that's involved with the maturing oite and so we call this the ovarian cycle so what we see is that gamine is being produced and maturing in the ovary the other cycle that is complimentary is the uterine cycle and this is going to be the process by which the uterus is going to be prepared for the possible fertilization and implantation of the fertilized egg which we call a zygote both of these Cycles run on a monthly process approximately run monthly calendar and they are going to function and symbiotically and function collaboratively let's start by looking at the ovarian cycle we're going to go through each steps and we're going to see how an oite under go maturation and then it will eventually be released from the ovary we call it ovulation and then we're going to look and see at what happens to the remaining structure that's in the ovary still following ovulation so this cycle this ovarian cycle is approximately 28 days give or take both this will differ within the individual and it will differ differ between individuals and we are going to divide this ovarian cycle into three phases or three events so we have two phases the first two weeks approximately are going to be the follicular phase this is when the follicle is going to be developing the second phase is called the ludal phase and this is going to be approximately the second two weeks and this ludal phase is going to occur after the event of ovulation and ovulation is going to occur when this oite this egg is released from the ovary so let's start with the development and maturation of this oid and so we're starting with the baby that has been born with these primary o sites that are in the arrested phase of meiosis one so we refer to these o sites as primary o sites and this is going to take place in the outer portion of the O ovary that we call the cortex this primary oi is going to be surrounded by cells that are dividing and these are called follicle cells and so this structure that includes the primary oite and the follicle cells in the female before puberty is called the primordial ovarian follicle so this is the follicle that the baby is born with and maintains through childhood however when puberty arrives there's going to be hormonal signals that's going to tell these follicular cells to become active and start multiplying dividing growing and now we refer to the follicle as the primary ovarian follicle so as these follicular cells are growing and dividing and multiplying we now say that they are forming what we call the Zona granular CLA so notice we still have a primary oite and it's surrounded by the Zona granulosa which is comprised of maturing follicular cells what we see happening is a unique complementary structure forming between the primary oite and the Zona granulosa and we call it the Zona palua and this is uh going to be structure that is going to consist of microvilli between these two structures and if we remember the purpose of microvilli is going to be to increase surface area and we find this in an area where there's absorption so not knowing the exact details of what's going on you can determine that there's going to be exchange of fluids nutrients waste products between the oite and these follicular cells now these follicular cells are going to continue to multiply and divide and we see that the follicle is beginning to appear differently and now we have re begun to refer to it as a secondary ovarian follicle now as these follicular cells are growing and PR proliferating the oite is also growing and and um maturing but it is still a primary oite so the stages of division have not continued on yet what you also see with the secondary ovarian follicle is they're going to release a fluid and this fluid is going to be begin to collect in an area or a chamber and we call this the Anum as this antrum begins to grow and become larger we can see that this follicle has differentiated and we now refer to it as a tertiary ovarian follicle you will also hear this tertiary ovarian follicle referred to as a graffian follicle or a mature follicle or mature graph follicle there's several different names but you can see that we still have a primary oite we still have the Zona granulosa some of that Zona granulosa has stayed with the next to the oite uh as this Anum it has become larger and larger now another anatomical and physiological change is Tak taking place as this follicle is becoming more and more mature is that there are cells in the surrounding tissue called theal cells these theal cells are going to begin to be to secrete chemical substances that are going to function with these follicular cells to produce estrogen so I'm just going to refer to the theal cells as producing estrogen even though it's it's a process notice where we are in the cycle we are approaching two weeks we are still in the follicular phase the follicular phase meaning that the follicle is maturing and developing we have not reached ovulation yet that tertiary ovarian follicle is growing and growing and growing and it is actually pushing on the wall of the ovary and is causing a bulge so we can see here that this this tertiary follicle is actually literally pushing on the edge of the OV here you can see a different follicle at a different phase of development very interesting now let's go back here where this illustration shows the phases of the FC phase that we are going through they're actually showing the whole ovarian cycle but going around this quote unquote Carousel of the ovary now development of the icle is not going to progress in this fashion going around the edge of the ovary as if it was the where you bag your groceries at Walmart but there is going to be movement of this follicle in the ovary during development and I don't know the details however um as the follicle is maturing and developing it will move either closer or farther away from the medulla uh because remember this medulla is where you're going to get the blood vessels and the nutrients that are going to help nourish the developing follicle and oite and then once the oite and the follicle is mature enough and we're nearing ovulation it's going to be need to be closer to the periphery of the follicle now I don't have details on exactly what's guiding the movement but there is movement it's just not necessarily going to be in this very specific Carousel type fashion I think this is stuff we've all uh covered previously the theal cells uh producing the estrogen uh they don't directly release estrogen they actually release uh androgens that are converted to estrogens with the fular cells but that's beyond the scope of this Coast this course and the corona radiata those are those granulosis cells we saw that are kind of hanging out still stuck to the oite uh it looks like a a star or a crown radiating out so what we see is going to occur next is there's going to be this surge of the lutenizing hormone released from the pituitary gland and this luteinizing hormone is going to initiate meiosis 1 to finish then my iosis 2 is going to start but once again it will not complete this phase it's going to be arrested and in fact the second phase of meiosis doesn't complete until if and until fertilization occurs now when we have meiosis 1 progressing to meiosis 2 we are going to have division of the cell but not equally so we do get a secondary o side but the other structure is going to be what we call a polar body and the polar body is just going to degenerate it from what I understand it contains material that is not useful or viable for functioning as an oite and it is released and it degenerates now this secondary oite that is now in meiosis 2 that is in the arrested State this is what is going to be released from the ovary in the event we call ovulation so we have completed the follicular phase which included the maturation development and maturation of the follicle from primordial to primary to secondary to tertiary and also the primary oite undergoing finishing the meiosis 1 beginning meiosis 2 and so it is now a secondary oite so it is going to be released from the ovary so we are about halfway through the ovarian cycle about two weeks we see that the oite the secondary oite is going going to be released from the ovary the uterine tubes are not connected physically to the ovy it is going to be in proximity and we have these finger like extension called fim that are going to have ciliated structures associated with them and you've got peristalsis and fluid movement probably that's going to help guide the oite into the uterine tu I don't know if they know exactly all of the factors that help assist that secondary oite arrive and enter into the uterine tube now our scientists like to say it's one follicle a month or one oite a month that is released each month with each cycle but as many of us know this is not always true because we have pregnancies Perfectly Natural perfectly healthy that are multiples in which more than one egg is fertilized so that means more than one egg had to be released this video can be helpful to you if you want to look at that I really like this illustration because it goes through the different V views of what is occurring during the OV ovarian phase so we've got the ovarian cycle at least up through the uh follicular phase so we've got the hystology slides to see all the way through ovulation we can see a drawing labeling all of the parts and then you can see the phases of the divisions now what happens to that follicle that's in the ovary that was housing the oite after the oite has been released with ovulation well now we are going to enter into the ludal phase of the ovarian cycle and so this is post ovulatory ovulation has occurred so the follicle that once housed that oite is now going to form what we call the Corpus ludum Corpus meaning body ludum telling you it's yellowy and this is going to be yellow in appearance because it contains a high amount of cholesterol and the cholesterol is there for a reason it is going to be used to produce that steroid hormone we call progesterone remember uh the ring likee structure of the steroids based on the cholesterol Rings progesterone is going to be functional we will learn in different ways it's going to help in the uterine cycle for the preparation of the uterine lining for potential implantation of a fertilized egg the although estrogen is still present it it does not play a primary role in this ludal phase as we saw it playing a role in the follicular phase this ludal phase and this Corpus ludum is going to be maintained for almost two weeks hoping that the ovom is going to be fertilized however if there is no fertilization of the ovom then this Corpus Lum will then differentiate kind of degenerate and become what we call the Corpus Albans Albans is telling you white so this is going to become a scar tissue and over time it will just degenerate into nothing so what we see is that we are losing the progesterone and even the estrogen uh that is being secreted from the ovary for this particular cycle and we have ended this particular 28 day ovarian cycle and it's going to start all over again