Female Reproductive System

welcome to this video on the female reproductive system let's go ahead and get started so we will start with coloring the musculature of the uterus in red so the uterus is a very muscular organ it's often described as being shaped like a pear and it's very small maybe about the size of a fist or smaller when a woman isn't pregnant and then it can expand and the walls thin out during pregnancy till it's about the size of a basketball and all of the stuff that we're coloring in pink is called the myometrium this is the muscle of the uterus you can see it's nice and thick and that allows it to be strong and to not stretch out too thin during the pregnancy and then also to still be strong enough to do contractions to push the baby out when the time has come so we're going to label this as the myometrium that word Myo means muscle and metrium always means uterus so this is the myometrium then let's use an orange for this nice epithelial layer on the inside called the endometrium you can hear right in there endo means inside and the endometrium this lining of the uterus is what nourishes a developing embryo and fetus endometrium so that word means inside the uterus and this is epithelial tissue now over here I have a little graph that shows you during a monthly cycle for a female the endometrium is sloth during what we call menses or a woman's period and so on day five you know period it depends on the woman how long it lasts but about five days is quite average and then it start thickening again for the rest of the cycle and if the woman becomes pregnant in the second half of the cycle then this lining will stay thick for the rest of the pregnancy but if she doesn't become pregnant then it will the cycle starts again she will slop it and then rebuild sloth and then rebuild and that's what causes the monthly periods throughout a woman's reproductive years so if the endometrium is growing in places where it shouldn't we call that endometriosis so we'll use the same orange pen sometimes endometrial tissue can grow on the outside of the uterus on the outside of the fallopian or uterine tube that you see here or on the outside of of the ovary itself so these situations can be painful for a woman and also make it harder for her to get pregnant okay let's go on to using a yellow and we will do the ovaries right here in yellow and the ovaries are the female gonads so they're equivalent to the testes in the male they're on the inside of the body and we'll label that with the black pens this is the ovary and there are two of them and every month under the influence of the hormone estrogen that an egg will mature and be ready to be ovulating so why don't we use green for the egg so it starts out and as the month goes on in what's called the follicular phase the egg matures until it's ready to be ovulated and then when it gets violated there do you see that ring right there there's a layer of cells that are left behind and they are actually yellow so I should probably put that in yellow too so right around here in that what gets left over is called the corpus luteum and only the egg then can't use on its way and so it's moving it takes about a week for it to move down the fallopian tube and then into the uterus and if it was fertilized it will implant in the endometrial wall so we could call this implantation if fertilization happens it should happen at some point in the fallopian tube so that's a key point we should put on here I'm gonna write it right here so fertilization occurs in the fallopian tube and then that little embryo starts dividing like gangbusters and it gets into the uterus and then implants so again this actually this boxed area is about where we would expect fertilization to occur it is pretty early on in the fallopian tube and then it continues dividing and then is implanted if no fertilization occurs then it will just pass out of the body and it's about the size of a dot of a pen and so you would not notice that okay I want to show you what the inside of the fallopian tube looks like over here let's do that in blue so these are real this would be like the walls of a fallopian tube and there are these columnar shaped cells and what is super cool about them is they have cilia on them so these are ciliated cells and they do the wave and then here's that little egg moving along imagine if it is going in this direction down the you know of the fallopian like fallopian tube like that and it should be moving through now what I've put here I imagine if you have some scar tissue in the fallopian tube and that can occur from infections like pelvic inflammatory disease so infection maybe like a sexually transmitted infection can scar the tube and in pee passage of the egg and that's bad for a couple of reasons it means that most likely the sperm also can't get through and the egg couldn't be fertilized or what's actually far more scary and dangerous is if the egg is fertilized but then it's impeded in its progress and implantation occurs in the fallopian tube wall instead of in the uterus where it's supposed to happen so if that implantation occurs anywhere outside of the uterus most likely in the fallopian tube then that is called an ectopic pregnancy obviously the fallopian tube is not designed to stretch the way the uterus is and so first of all this would be extremely painful but worst of all it could actually rupture the fallopian tube and the mother could bleed to death so this is considered an emergency situation and I think over here we can go ahead and label this as the fallopian tube also called the uterine tube there's two of these so every month an egg is ovulated from one ovary or the other not both in the same month if a woman ovulates multiple eggs in one month then that would result in twins or even triplets if it's three eggs and they would be fraternal because each egg could be fertilized by a separate sperm so maybe we could put that right here so fraternal twins that word fraternal just means like brothers or siblings that would be two eggs ovulated and some women are genetically predisposed to do this and so it would require two eggs two separate sperm that's different from identical twins identical twins are when one egg is fertilized by one sperm and then it splits into two completely separate cells very early on in embryonic development and then two fertilized eggs are implanted but they were from the same original egg so this is one egg is fertilized splits so early in development that the genetic code is there to start an entire all the organs that are necessary for another baby so they're going to have a night identical DNA to identify lettuce and this seems to be spontaneous doesn't seem to run in families as much as fraternal twins do okay so sometimes what happens is that there are cysts that develops I think we'll go back to pink I've already gone through all my colors cysts can develop on the ovaries and they might be kind of left over from an ovulated egg or maybe an egg that never ovulated and they can arise from different circumstances but right here I have labeled this would be an ovarian cyst and I think probably most women get them at least a few times in their life and it can cause some pain but then it eventually will rupture and release the pressure certain kinds of hormonal like birth control methods can make it more likely and also some women can have hormonal imbalances such as polycystic ovarian syndrome and that can also cause them to be more likely to have those cysts so if we look down here at our graph estrogen is the important hormone that causes the thickening of the lining and I have it right here I'm gonna use a green highlighter so this line represents how estrogen changes in a woman's body over her one-month cycle so it's very low during the period and then it goes up high and this typically is a time when a woman is going to feel pretty good she has a nice amount and then there's a bit of a dip right after this line is when ovulation of the egg occurs about day 14 then it might go up a little bit in that second phase but then drop off and this would be when people talk about having PMS do you see how the hormone levels are dropping off so the green line represents estrogen and estrogen is the dominant hormone that causes secondary sex characteristics in a female so this would be like breast development smoother skin hip development and also egg maturation so because it's really busy during the first part of the cycle we call this the follicular phase because the follicle is where the egg develops in the ovary and then a hormone called luteinizing hormone spikes to cause ovulation so why don't we put that in blue right here ovulation is marked usually it occurs on day 14 and it's caused by an LH spike so this hormone comes from the pituitary gland and it caused this big spike is what causes that mature egg to finally be ovulating the female will also at this time have a temperature spike that stays for the remaining two weeks so unlike a male whose body temperature might remain roughly the same all the time a female will have let's say a body temperature of like 97.5 for the two first weeks and then it will go up to 98.5 for the next two weeks it's gonna vary depending on the woman but that's pretty typical so 97.5 and then up to 98.5 for the last two weeks and then the third really interesting thing that happens that will help pregnancy to be more likely to occur is she has a thickening of the cervical mucus and that is going to help hold sperm near the uterus so that they're more likely to survive and make it up the fallopian tubes so the second hormone then is see I think I'll use a pink right here this would be for progesterone will do in pink and notice that it's pretty low during the first two weeks and then it goes much higher but then it also will drop off if pregnancy doesn't occur pregnancy does occur it will stay I guess I could go like this it will just continue to stay high throughout the rest of the pregnancy so progesterone in pink is the hormone of pregnancy so all of the body changes that we think of for pregnancy are because of progesterone okay so that is the dominant hormone of the luteal phase that second-sight part of the cycle so everything is set for pregnancy right you have a sloughing of the lining and then a building up a building up a building up and then you have estrogen increasing increasing increasing and then it dips but then goes back up again if pregnancy doesn't occur it drops off progesterone is low in the follicular phase and then it's very high in the luteal phase and if pregnancy occurs it will remain high for the whole rest of the pregnancy so let's go ahead and talk a little bit about that cervix we can do that in blue right here so the cervix is a little opening from the vagina up and to the uterus and the cervix protects the opening to the uterus but in order to allow sperm through it does have a thickening of mucous right here during ovulation and then if intercourse occurs then the sperm will make those in black some sperm then the mucus will help them stay up there and the semen should have alkaline substances in it so that the acidity of the vagina right here is not so much that it kills off the sperm the vagina is very muscular and it contracts during orgasm and not only does that feel good for the woman during orgasm but what's really cool about this too is that the cervix during orgasm will kind of dip down a little bit like this from those contractions and is more likely to grab more of the sperm that might be deposited there and then the sperm will swim up the uterus and a few hundred will go every couple of hours and they sow fertilization will actually happen in the fallopian tube way over here and then there will be sperm that go the wrong way to the way that no egg is on that particular month and so these ones would not have the opportunity to fertilize an egg so you know there's millions of sperm down here and every few hours they go in a group of maybe one or two hundred and go and see if they can find an egg they can live for about five days here and so if someone has sex before they ovulate then let's say on day ten there's still sperm that would be alive and swimming up on day 14 when she obvious so if a woman has sex before she obviates there's still a decent probability that she could get pregnant if she has sex at the time of ovulation that would also be a good chance that she would get pregnant if she has sex after she obvious more than like a day after she obvious then the likelihood is much lower because the egg itself has to be fertilized within about 24 hours maybe we should put that here must be fertilized within about a day of being ovulated and then it takes about a week to reach the uterus in those little cilia help wave it along and keep it moving okay so just a little bit of a recap I want to make sure I covered everything pelvic inflammatory disease or some sort of an infection can scar the fallopian tubes and make an ectopic pregnancy more likely endometriosis is when parts of this nice epithelial lining called the endometrium grow on the outside of the uterus the outside of the fallopian tube or the outside of the ovary ovarian cysts are caused by hormonal imbalances so the hormones would probably not be looking like this and they cause like the egg to not be fully mature or not to be fully ovulated and so then a cyst can develop on the outside of the ovary ovulation will occur at about day 14 and it leaves behind off there's something I forgot to tell you it leaves behind what's called the corpus luteum and that means the yellow body so luteum means yellow corpus means body and I want to say something else about this this is where progesterone comes from so it's the source of the progesterone for those last two weeks and actually throughout the entire first trimester of the pregnancy at the end of the first trimester of a pregnancy the placenta which will be developing and here will take over that role but for those first few weeks the corpus luteum is where it's at releasing progesterone and maintaining the pregnancy and also maintaining the uterine lining those during the luteal phase of the cycle okay so the dominant hormone for secondary sex characteristics is estrogen this is the hormone that makes a female's body change when she goes through puberty progesterone on the other hand is the hormone of pregnancy it is what makes all of the pregnancy changes occur in the body during pregnancy the sperm during intercourse will be deposited near the cervix the semen is sticky and alkaline and the mucous from the cervix is also alkaline and thickened and so that will help the sperm survive millions of sperm are deposited here can survive for about five days and every couple of hours then 100 or 200 of them will go and swim up to both sides and then they may or may not be able to fertilize an egg the first two weeks of the ovarian cycle are called the follicular phase that's when the lining of the uterus is building up again and then the luteal phase caught its cause called that because that's when the corpus luteum is releasing progesterone that you see here in pink and really causing progesterone to be the hormone that's in charge those second two weeks and if pregnancy occurs it maintains being in charge ovulation can be identified with a luteinizing hormone spike and then d sure that luteinizing in there so this LH spike is a hormone that causes ovulation which means the corpus luteum gets left behind so we've got the corpus luteum means yellow body when that yellow body is making progesterone we call this the luteal phase and it's the hormone luteinizing hormone that causes ovulation so they all have that root luteal in them okay I will see you in the next video

Channel: susannaheinze

Views: 64,165

Rating: 4.8916826 out of 5

Keywords: female reproductive system, ovaries, fallopian tubes, myometrium, endometrium, endometriosis, ovarian cysts, progesterone, estrogen, LH, FSH, corpus luteum, follicular phase, luteal phase, ovulation

Id: eRtFnWWB-cM

Length: 21min 39sec (1299 seconds)

Published: Fri May 24 2019