Overview of Male and Female Reproductive Systems

Chapter 28 The Reproductive System In this chapter we're going to cover the reproductive system of the male and the female without pregnancy. Chapter 29 is going to cover pregnancy and fertilization. So the reproductive system we're first going to talk about in general and then we'll talk about male first followed by female. So the reproductive system in male and female functions in gamete production. Gamete of course being a sex cell whether that's egg or sperm. So the gametes are going to be produced then stored. nourished by the reproductive system, and finally transported. Fertilization is defined as the fusion of a male and female gamete together to form what is called a zygote. Now we should remember that a human cell is made up of 46 chromosomes. So a male sperm will carry 23 of the father's genes, and the female egg will carry 23 of the mother's genes. So when those two gametes combine, we have a 46 chromosome zygote, which will be exactly half mom and dad. Now that's about all we're going to say for fertilization. right now as we'll save that for chapter 29. So the reproductive system is going to include whether in male or female gonads which would be either the testes or the ovaries, ducts which will carry the gametes from the gonads out of the body, and accessory glands and organs that are going to contribute fluids to the reproductive system, and finally the external genitalia. In males, the testes produce spermatozoa. Spermatozoa is a fancy word for a mature sperm cell. Men make about a half a billion every single day of their lives. average. There's a high end and a low end to that. And they're expelled from the body in semen during ejaculation. It's important to know that the sperm cells are the actual tadpole-like cells in the semen, which is the fluid that surrounds and nourishes those cells. So when we say semen, it only refers to just the fluid part of ejaculate. Females, the ovaries produce oocytes. An oocyte is an immature egg and it's also important to know about the difference between female and male is that males produce sperm every day once they release puberty. the way through their entire lives whereas females only make eggs before they're born so a baby girl on her very first day of life already has all the eggs she will ever have in her entire lifetime she will never make new ones and those eggs will lie dormant until she reaches puberty when they will begin releasing one a month throughout her reproductive years but girls do not make new eggs once they're are born. They only have the ones they're born with. Once those eggs are released during each month's ovulation, the egg will travel along the uterine or fallopian tube toward the uterus and the vagina connects the uterus with the exterior of the body. So for females we're going to get into them in detail in the last half of the chapter. So we'll start out with males first. The reproductive system of the male begins by talking about the pathway of sperm. And in your notes that I've given you, on your outline, you have a little acronym, 7UP. And 7UP, each one of those letters, stands for a part of the pathway of sperm production and release. So let's start with the S, and we'll fill that in with seminiferous tubules. Seminiferous tubules are located inside the testicle In this picture, we're looking at a mid-sagittal section of the male pelvis We can't actually see inside of the testicle in this picture The seminiferous tubules are tiny little coiled up tubes that are located inside the testicle Those little tubes are where sperm production first takes place are formed in the seminiferous tubules, they then will move to the E part of 7up, which is the epididymis. And that's what this is right here. This structure that hangs on to the back of the testicle. Now of course remember we're only looking at half the picture. There is one testy here and one epididymis, but we know that there are two testicles, so that means there are also two epididymis. Okay, so the epididymis. is on the back of the testicle and then once the sperm are produced and moved to the epididymis they will then enter what's called the vas deferens which is the V in 7up the V in 7up now your book has has started adopting this new term ductus deferens I want you to know that ductus deferens is the same thing as the vas deferens Vast deferens, but I like to use vast deferens because it fits in our 7up So the vast deferens is a series of tubes. There's one for each testicle so we can see one here It's a tube that goes all the way around the back of the bladder. Okay, of course, here's the bladder so we're going all the way around the back of the bladder and Once we get through the vast deferens the vast deferens then Urethra Urethra Out through the penis One more time One more time Testicle Epididymis Vast deferens All the way around Back of the bladder Ejaculatory duct Urethra Out through the penis That seems like quite a loop And that seems like quite a loop It takes several weeks for sperm to fully mature enough to where they are able to fertilize. That long pathway gives sperm time to become mature before they are released. Now that we know the pathway of spermatozoa, which again are mature sperm cells, we then have to talk about the accessory organs. groups of accessory organs we have the seminal vesicles the seminal vesicles the prostate gland and the bulbourethral gland so we'll take a look at where those three are and then a little bit later we'll talk about what they secrete the scrotal sac encloses the testes and of course the external genitalia being the penis so in this picture here we can see the prostate gland which we learned about in urinary system is right below the bladder then we have the seminal vesicles of which there are two on the back of the bladder here and the bulbourethral gland which is located right there okay so those three accessory glands So we'll first talk about the descent of the testes. When a baby fetus is forming, a baby boy, his testicles actually start up very high in his abdomen up near the kidneys, which is certainly a long time. from where they should be so as fetal development continues the testes should descend into the scrotal sac so we'll look at a picture of how this happens now this is a two month old fetus This is not a 2 month old infant, this is a 2 month fetus. Very tiny, maybe the size of a peanut. This is the pelvis that you're looking at here. The umbilical cord. There's the testicle way up near the kidney. There's the scrotal sac way down here. There's a cord that attaches the testicle down into the scrotal sac. And that cord has a very ridiculous name, gubernaculum. testy and that name as bizarre as it is is the cord that actually attaches the testicle to the scrotal sac now when you look at a picture like this it's sort of It looks as though maybe that gubernaculum testi will shrink and kind of reel in the testicle to the correct location. But that actually is not at all what takes place. The gubernaculum testi never changes in... length, but the baby's pelvis enlarges and lengthens, so this will allow the testicle to end up in the right place at the end of fetal development. We know this because we can see at two months, this right here is the measurement. of the length of the gubernaculum testes, five millimeters, which is quite tiny. Here we are at three months fetal development. The testicle is much lower. The gubernaculum testes still measures five millimeters. The baby's body has just gotten bigger. And at birth, right before the baby is delivered, we still have a gubernaculum testes and it's still five millimeters in length, but the baby's pelvis has gotten much larger. and has lengthened which has allowed the testicle to end up in the right place by the time birth occurs this is a frontal view of the same process and we can see how the gonads or testicles are way up near the kidneys but as the months pass the testicles begin to descend descend and descend until at birth they should be located within the scrotal sac So there is a very important set of muscles in the scrotal sac and the first is the dardos muscle The dardos muscle wrinkles the scrotal sac And what it's basically doing Is the wrinkles in the scrotal? sac that muscle bunches up the skin and so it's basically a storage area for the skin that's not used when there is not an erection when there is an erection there is a need for more skin so the skin is not in use the dardos muscle wrinkles it and holds it bunches it up on the scrotal sac the cremaster muscle is a very important muscle because it's it's a skeletal muscle and it actually pulls the scrotal sac close to the body in response to temperature the testicles need to be at least two degrees Fahrenheit lower than body temperature in order to have healthy sperm count so if It is extremely cold. The Cremaster muscle will pull the scrotal sac close to the body to keep it warm. If it's very warm, the Cremaster muscle relaxes and allows the scrotal sac to drop away from the body, which keeps them from overheating. So that muscle on its own will help to determine whether or not the scrotal sac needs to be closer or further away from the body based on temperature. Thank you. The testicles are also surrounded by a special membrane called the tunica albuginea. The tunica albuginea is a fibrous membrane that surrounds the testicle and divides the testicle into lobules. And the lobules are separated by septa. Okay, so we'll look at a picture of this so it'll make a little bit more sense. Now before we look at the testicle on its own, we can look at the musculature of the scrotal sac in this picture here. Here we can see the testicle and epididymis are cut deeper. On this side, the testicle is surrounded by a muscle, which is colored in a red. That's the cremaster muscle. Then we have the skin, and right under the skin is the dardos muscle. The one that wrinkles the scrotal sac when the skin is not in use. Cremaster, dardos, and skin. than the actual skin. Okay, so if we look at this picture of the testicle, this is a picture of the testicle's sliced transverse. Okay, so we can see inside each scrotal cavity. So here's the actual testicle, and we can see some skin. The dark area is the scrotal cavity Then we have the cremaster muscle The dardos muscle and the skin If we focus on the testicles We can see that the testicle is surrounded by a membrane called the tunica albuginea and that tunica albuginea Actually pushes into the testicle and divides the testicle into lobules And you can see almost like the segment of an orange in a way little triangular sections each one of these lobules or triangular sections is filled with seminiferous tubules which was the S in our 7up that we talked about when we talked about sperm production those little coil up tubes are where sperm production actually takes place okay so we have the S for 7up the first S seminiferous tubules located in the lobules of the testicle So in the seminiferous tubules is where sperm production takes place Not only do we have sperm production happening in the testicles, but also sex hormones are produced like testosterone Once the sperm are produced they'll pass through what's called the reet testes into the efferent ductules finally to the epididymis so if we go back to this picture here we can see the pathway so we know that that the first S is seminiferous tubule which is what this is here so once the sperm is produced it will then be pushed into this area which is called the rete testes the rete testes will then pass the sperm into the efferent ductules and then the epididymis okay so again seminiferous tubules rete testes efferent ductules into the epididymis, which is the first E in 7UP. So we're going to look a little closer at how this actually happens, and the process is called spermatogenesis, or the creation of sperm. And of course it begins in the seminiferous tubules, and it starts with stem cells called spermatogonia. Spermatogonia are stem cells that are constantly dividing. They're constantly making new sperm. sperm cells. The spermatogonia will divide and create new cells and those new cells will continue to change until they become mature sperm cells. So we'll take a look at that process. Along with the spermatogonia we also have some special cells called sustentacular cells which are going to sustain and promote the development of sperm, sort of nourish them as they are developing. So let's take a closer look at spermatogenesis. We'll look inside the seminiferous tubule and you can see this on page 1047 of your textbook. This is a microscopic view of the seminiferous tubules that have been sliced. So we're taking one seminiferous tubule and we're blowing up the one seminiferous tubule to see how sperm are produced. And in this picture here, we can see that the sperm are being produced in the wall of the seminiferous tubule. So what I want to do now is take this one little piece of wall right in here, and I want to blow that up a little bit closer so we can see what's going on in these cells. Okay, so in the seminiferous tubule we have two areas we need to be aware of This is the outside of the seminiferous tubule right here And this is the lumen which remember is the hollow inside of any organ so this This is the hollow inside of the tube and this is the outside of the tube. Down here at the very bottom is the spermatogonia, which are the stem cells. The ones that make new sperm. All down here is spermatogonia. Spermatogonia will divide to produce primary spermatocytes. Primary spermatocytes. Primary spermatocytes will become secondary spermatocytes, which are these guys here. Secondary spermatocytes become spermatids, which are these. And spermatids become spermatozoa. which are mature sperm cells. So we started at spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids, and then spermatazoa which are the mature sperm cells. But how do we go from spermatid to spermatazoa? As you can see these guys don't look anything like these. There's no tail, there's no neck, there's no head. So there's got to be a lot of change that's going on between here and here. So we're going to look at that next So each spermatozoon and spermatozoa The spermatozoan is one spermatozoa, one mature sperm cell. So each mature sperm cell has three parts. A head, a middle piece, and a tail. The head contains... This is dad's DNA. 23 of the father's chromosomes packed into the nucleus. The middle piece contains mitochondria that are going to power the tail. We know sperm are very active. They use their little tails to swim and that's how they try to get to the egg so the mitochondria need to be strong producing lots of ATP for the tail to move and the tail is the only flagella in the human body Alright so in this picture, which is figure 28 28 this is found on page 10 51 of your textbook and it shows how we we go from spermatid to spermatozoa to mature sperm cell. The main reason that there's such a big change is not only that we need the sperm to be mobile so that they can move through the female's body to get to the egg, but also sperm need to be lightweight and very small. They have a long trip ahead and they don't need to be carrying around a lot of extra baggage. When we start at this spermatid, you can see that the sperm The sperm has a lot of organelles and cytoplasm and it has no way to move. There's no flagella. As time goes through the sperm to the spermatozoa, we're going to start whittling down the body plan of the sperm. We're going to start shedding off cytoplasm, which will include organelles we don't need. We'll continue to shed as... As we develop a tail, and once we've shed off all the extra organelles and all the extra cytoplasm, we're left with a mature sperm cell at the end of this process. And the mature sperm cell, again, has a head, which contains 23 of dad's chromosomes, a neck piece, which has mitochondria that will make energy for the tail. But there are no other organelles involved. This sperm there's no Golgi. There's no er. There's no ribosomes. There's none of that stuff all of those things Will be supplied by the mother's egg the sperm just needs to carry dad's chromosomes to the egg when the time comes Alright, so once the testes produce mature sperm cells, the sperm will enter the first E in 7UP, which is epididymis. The epididymis is an elongated tube with a head. It's going to be used to monitor and adjust the fluid in the seminiferous tubule. It's going to store and protect the sperm cells and also give them time to to mature. Once the sperm cells move into the epididymis, they're going to spend about two weeks getting through the epididymis, which is a maze of tubes. And that two-week period will allow the sperm to start maturing even further to become prepared for when they might possibly enter the female's body. So this is a picture of the testicle and epididymis on page 1052. of your textbook. Here's the testicle course and the outside of it is covered with the membrane the tunica albuginea. Each one of these is a lobule that contains seminiferous tubules. The seminiferous tubules will produce sperm and push them into the rete testes where they go through the efferent ductules into the epididymis which is this area here. here on the back of the testicle. So once the sperm enter the epididymis, they'll take two weeks just to get through this one little epididymis before they enter the vas deferens, which is the V and seven up. The vas deferens begins at the epididymis and passes through the inguinal canal and enlarges to form the ampulla on the back of the bladder. The ejaculatory duct at the base of the seminal vesicle and the ampulla will join together and form the urethra. Okay, so we're going to go... Fat so that I can show you the vast deference and how it joins together with the seminal vesicle into the ejaculatory duct and we'll take two views of this. So here comes the vas deferens around the back and it joins with the seminal vesicle, which we haven't really talked about yet. This is a gland and the ejaculatory duct and then feeds into the urethra and out. So let's take a view of the back of this right here so we can see it a little bit more clearly. Okay, so this picture is on page 1053 of your textbook and it shows how all of these tubes join together. So we have here the vas deferens from one side and the vas deferens from the other testicle. The vas deferens enlarges on both sides to form what's called an ampulla. It's a swollen portion of the vas deferens. The two swollen ampulla join together With the seminal vesicle glands, all four join together to form the ejaculatory duct which runs right through the prostate. The ejaculatory duct then feeds into the urethra which will exit the body. So the urethra has three regions, the prostatic, membranous, and penile. So if we look at all three of those regions, we can see why they each have their names. The prostatic urethra of course is going through the prostate the membranous region is In between the prostate and the penis and then this is the penile urethra so penile membranous prostatic of the total volume of semen. The seminal vesicle fluid contains three major things – fructose , prostaglandin, and fibrinogen. Fructose or the sugar in this secretion is going to give the sperm mitochondria the sugar they need to produce energy or ATP The prostaglandin will cause contractions in the male and female reproductive tracts the prostaglandin will cause spasming of the male reproductive tract helping to get rid of all the semen and once the prostaglandin actually enters the female's body it causes her vaginal canal to contract which will pull more semen in that the thought is to increase the chance of pregnancy and fibrinogen causes a temporary clot of semen in the vagina so the semen thickens up when it enters the vagina because of fibrinogen which helps more of its stay in the vaginal canal less of it can run out The prostate gland secretes slightly acidic prostate fluid and it contributes about 20 to 30 percent of the secretion. And the fluid is slightly acidic which the prostate, it's not fully understated. all the functions that it may have but one thing that we do know is that the prostate is likely one of the reasons that men are less likely to develop urinary tract infections because the prostate acidic fluid can inhibit bacterial growth. The bulbourethral glands, which secrete around 10% of the semen, is an alkaline mucus with lubricating properties. Bulbourethral fluid is what's often referred to as pre-ejaculatory fluid. It's kind of a clear mucus and the bulbourethral fluid, what it does is it actually coats the inside of the bulbourethral glands. So, it's a of the urethra before ejaculation and the idea is to lubricate the penis but to also neutralize urinary acids because remember men use the urethra for urination and also ejaculation so if there is a urinary acid residue in urethra it could potentially harm the sperm when the sperm move through the urethra during ejaculation. So the vulvo urethral glands are going to neutralize the acid to create a safe passageway for the sperm when they actually come through. So the typical ejaculate is only 2 to 5 milliliters of fluid and it contains between 20 to 100 million sperm per milliliter so that could be on the high end 500 sperm per ejaculate. Now whenever we call a man sterile, a lot of times people think that he has no sperm in his semen, but that's not actually true at all. It just means that the sperm count is so low that the chance of any sperm actually making it as far as the egg are very slim. And we'll talk about why that is when we get into reproduction in chapter 29. So overall, seminal fluid is a distinct ionic and nutritive glandular secretion. Overall semen would be considered extremely basic. The reason for it, and when I say basic I don't mean simple, I mean basic on the pH scale. It's considered basic because the female's body is terribly acidic. So without the coating of semen around the cells, the female's acidic vaginal canal would likely kill many of the sperm and make it less likely for pregnancy to occur. The male external genitalia consists of the scrotum and the penis, and the skin overlying the penis resembles the scrotum. The penis contains three masses of erectile tissue, two corpora cavernosa, and one corpus spongiosum. The dilation of that erectile tissue is what produces an erection. So if you look on page 1055, we can see how the spongy and cavernosa tissue is located inside the penis. So here we have these purple cylinders. are the corpora cavernosa. Each one surrounds an artery and below that we have the corpus spongiosum which surrounds the urethra. So these three cylinders of erectile tissue, if we were to take a transverse section and look at that, that's what this is. We have corpora cavernosa, another corpora cavernosa, each surrounding an artery and then below that is the corpus spongiosum. surrounding the urethra. When these spongy tissues are engorged with blood this is what creates an erection. Male reproductive hormones. First we have FSH which is of course follicle stimulating hormone and its job is to target sustentacular cells to promote spermatogenesis. LH will cause secretion of testosterone and other androgens Gonadotropin releasing hormone is going to also help with sperm production And testosterone is the most important androgen, not only because it assists in sperm production, but it also is going to give men their secondary and primary sex characteristics. Okay, so we'll now move into the reproductive system of the female, which is the second half of chapter 28, and it begins on page 1060. And if you recall... Believe in a couple of other chapters or maybe one other chapter. I showed you some ads from the 30s Just to show you how far things have come and this one says you may think she's just your gal But she may be everyone's pal so Prophylaxis prevents venereal disease nice way to say wear a condom, which is kind of forward for that time And then this one is pretty awesome This one shows how a woman this woman here is held in a web of indifference Her husband does not care about her. He's not interested in her and the reason is not because of anything significant really but Because she hasn't douched with her Lysol Because apparently Lysol used to be the doctor's number one douching agent I cannot imagine how painful that would be but apparently didn't you could use it to disinfect your floors and also After Lysol, her husband is extremely interested in her again. Many doctors recommend Lysol for feminine hygiene. for six reasons and it just gives us one. It's much safer it says than homemade douching solutions. For feminine hygiene use Lysol. That is extremely ridiculous and there's no gynecologist in this time period that would ever suggest you use Lysol. Okay so the main organs of the female reproductive system are the ovaries, the uterine tubes, which used to be called fallopian tubes, tube so I will probably always say fallopian tube but your book is going to refer to it as a uterine tube the uterus and then of course the vagina or vaginal canal the ovaries uterine tubes and uterus are enclosed within a broad ligament and the mesovarium is going to support and stabilize the ovaries so we'll look in a second at some of those ligaments and mesovar But first we'll take a look at the basic female anatomy. So this is a mid sagittal section through the female reproductive tract found on page 1060 and we can see here we got the the pubic bone there the bladder and the urethra and Then here of course, we're only looking at half the picture. We've got a fallopian tube ovary pear-shaped organs figure This is the uterus and right here at the bottom of the uterus is the cervix and then the vaginal canal. So we're going to look at these in steps. The ovaries are held in position by ovarian and suspensory ligaments and blood vessels enter the ovary at what's called the ovarian hillus. And we've used that word many times at this point, so you probably remember that that's just where blood vessels and nerves enter an organ. And tunica albuginea, just like in the male reproductive system, is a membrane that covers the ovary. Alright, so this picture is found on page 1061 of your textbook. And it is a picture of the uterus, which again is a pear-shaped organ. The uterus is almost entirely muscle. It's just a big, thick muscle. Vaginal canal and cervix Cervical opening is where childbirth must occur It has to get to be 10 centimeters open, which is extremely wide in comparison to what it normally is then up here we have fallopian tube on the left and fallopian tube on the right and each fallopian tube is aligned with an ovary on both sides and of course the ovary is where we're going to find the eggs that were already created when the female was first born you Here we have an ovarian ligament. This is going to attach the ovary to uterus. And this thing that looks like wings is the broad ligament on either side. And the broad ligament is going to anchor the uterus into the abdomen or into the pelvis. And the main reason for this is the uterus does a lot of moving around. Even during your menstrual cycle, the uterus is going to contract to help rid your uterus of the blood that it doesn't need since pregnancy did not occur. When the uterus does become fertilized, the uterus has to grow many times its size. We'll have a baby in there doing gymnastics. Because of that, we have to have this ligament to hold the uterus in place. To give it a little bit of anchorage as it goes through all these major changes. So, oogenesis. Oogenesis is the production of the egg. And we already alluded to that oogenesis occurs before a woman is ever born. So, every newborn girl already has all the eggs she'll ever need for her entire life and she'll never make new ones. It's often said, it doesn't sound very good, but it actually is good, that for men it's quantity not quality. And what that means is that men produce just ridiculous amounts of money. They have had ridiculous amounts of sperm their entire life. And they're produced in such mass production that every single one of them can't be perfect. So even the most healthy of men do have a lot of sperm. have some sperm that are not so great. Some that swim in circles or have big big tails or tails that double tails that end up swimming and bumping into things and those are sperm of course we don't want to make it. But that being the case many of those sperm will die off as they begin to trek to the egg. So there's not not every sperm is top quality but for women because we only make eggs once in our life we have to take care that those eggs are as perfect as possible. So for women it's about quality, not quantity. We have a fraction of the amount of sex cells that men have, but ours have to be perfect because we've got such a precious few. So once we have formed our eggs, which is before birth, then those eggs will lie dormant until we reach puberty. Once a girl reaches puberty, she will begin to release one egg a month in what we call a ovulation. This is going to refer to our next thing which is the ovarian cycle. The ovarian cycle is two phases. We have the follicular phase which is pre ovulation and the luteal phase which is post ovulation. The follicular phase pre ovulation let's first remind ourselves or if you've never heard this before. The females reproductive cycle lasts approximately 28 days. 28 days on average. So thinking about the average female, pre-ovulation would be half of that. The first half. So the first 2 weeks or the first 14 days. So day 1 up to about day 14 is pre-ovulation. Ludio- Day 14 is post ovulation Day 14 is when we would expect ovulation So the ovarian cycle is going to cover some steps the formation of the primary secondary and tertiary follicles then we have ovulation and after that Formation and Degeneration of the Corpus Luteum Degradation of the Corpus Luteum This is on page 1063 of your textbook and what we're doing here is we're actually looking at the cortex of the ovary so the ovary has two parts it has this outside perimeter which is the cortex and the inside is the medulla so in the cortex of the ovary if we take one little chunk and we blow it up this is the cortex of the ovary okay this one little picture and in the cortex we can see some little structures here the These are oocytes. Oocyte being immature eggs. These are immature eggs. These are the eggs we've had since the day we were born, if you're female. These are called primordial follicles. Now the first thing we need to do is write down what a follicle is. A follicle is a secretory sac or gland. A secretory sac or gland. Each follicle has a secretory sac. Each oocyte is surrounded by a follicle. The follicle is a cushiony, pillowy sac that surrounds, protects, and nourishes the egg. Each one of these oocytes has around it a follicle. This is called primordial follicle because primordial means that it's been there since the beginning of your time So since the day we were born we've had those eggs So this would be day one Day 1 of the 28 day cycle There is going to be a spike in hormone around day 1 and that hormone will be FSH or Follicle Stimulating Hormone which makes sense because we want to stimulate those primordial follicles so follicle stimulating hormone would be perfect for that job so we'll have a spike in FSH which will cause FSH and FSH will cause FSH and FSH will cause FSH and FSH will cause FSH and FSH and FSH and FSH which will cause FSH several follicles to become activated. Okay, so this is an example of what could happen. So here we have two follicles that have become activated and each follicle contains an oocyte. Alright, notice that the follicles are primary follicles and the oocytes are primary oocytes. Now the oocytes and follicles are not going to mature at the same time. same rate so we need to be careful to note when they're primary, when they're secondary, when they're tertiary. So I'm going to be sure to point that out as we go down the line. So here we are at the beginning of the cycle day one and we're going to have a spike in FSH. FSH will cause the stimulation of some follicles. In this example we have two. Each follicle contains an oocyte. So right now we have primary follicles. and primary oocytes. You can see the faint outline of the follicle around the oocyte. One of these follicles will be selected to move to the next step. The other will disintegrate. So it looks as though this one is disintegrated and we're going to move this guy over to the next step. So as time continues on, this particular follicle and oocyte are selected. to become the secondary follicle. So here we have a secondary follicle, which is a big swollen follicle that's taken on a lot of fluid. And then we have in it the primary oocyte. Primary oocyte. So the oocyte is still primary, but the follicle is getting bigger and more swollen. And we now call it the secondary follicle. The secondary follicle then enlarges. The egg is huge and has accumulated a ton of fluid and the egg has not changed at all. The follicle has matured and matured. The egg has not changed at all. The follicle has matured and matured. The egg has not changed at all. So at this point the tertiary follicle is so large that it will actually create a bulge on the surface of the ovary and That bulge on the surface of the ovary can sometimes cause what we call Ovulation pain if you've ever had any tenderness This is a good time to get your ovaries open for soreness Here we are creeping up on the pelvic region There are two major things One, ovulation But it's also going to cause the primary oocyte to become secondary So we're going to have our first maturation So here we are at ovulation. This is an actual picture of the surface of the ovary with the egg bursting out. So this is day 14 ovulation. The egg is going to pop out and as that luteinizing hormone caused the egg to mature, we now call the egg... your oocyte secondary. So on day 14 it becomes secondary and that little oocyte will begin floating down the fallopian tube for a possible chance at pregnancy. So we'll we'll pick up there in just a minute, that as the egg pops out of the ovary and begins to move down the fallopian tube, the egg will leave behind some follicular cells. Those follicular cells will become egg does become fertilized, then the uterus will be ready to accept the egg and to start the development of an embryo. So the corpus luteum will remain in the ovary until it's determined whether or not we're pregnant. into three areas we have the infundibulum the ampulla and the isthmus infundibulum ampulla and the isthmus and you can see those three regions on page 1066 of your textbook so we're going to take a look at those three regions and I'll point them out for you they're also part of your lab Okay, so uterus here Then we have the fallopian tubes on either side and the ovary So the three regions of the uterine tubes are we have the fifth which are the little finger-like projections on the end of the fallopian tube. The fimbriae are attached to the infundibulum. Then we have the ampulla and the isthmus, which is what's attached to the uterus. Infundibulum, ampulla, isthmus. The uterus is a very muscular organ that's going to mechanically protect, nutritionally support, and remove waste for the developing embryo and fetus. It's supported by the broad... ligament and three pairs of suspensory ligaments. We looked at the broad ligament. So what this is saying is the uterus is used for nothing other than development of the embryo. This is a list of some of the major anatomical landmarks, which we will point out here in this next picture, which you can find on page 1067 of your textbook. Okay, in this picture we can see the uterus has been cut open so that we can see the inside details We have here the uterine cavity, which is the hollow inside or lumen of the uterus We have the fundus, which is the Raised top superior portion of the uterus Of course fallopian tube Ovary Broad ligament Then we have down here the internal os of the cervix Cervical canal Exterior portion of the cervix Cervical os Vaginal canal So if we were to do a cross-section through the uterine wall, okay right here, if we were to cut a chunk through here, we would see three layers. The innermost layer, middle layer, and the external layer. This is the endometrium, myometrium or muscle, and then the perimetrium. So let's go back a little bit and look at that. So the myometrium is the muscular layer and because the uterus is not under our conscious control, it's smooth muscle, the endometrium is the thin inner lining of the uterus that's what changes in thickness to The parametrium is a serosa that covers the outside of the uterus. We can look at those three layers in this picture which is on page 1068 of your textbook. Here's the lumen of the uterus, the inner layer of the uterus, or the hollow inside. Then we have the endometrium which is the inner layer of the uterus. Uterus layer Myometrium All muscle Perimetrium Outer covering or serosa of the uterus Now we're going to talk about here in a second the uterine cycle which is the menstrual cycle and in order to understand it a lot of times people want to know where does the blood come from And why does that happen? well, once you've ovulated and The corpus luteum is released that corpus or corpus luteum develops the corpus luteum will begin to release Progesterone which thickens the uterine lining in preparation for pregnancy So you can see here that the progesterone has thickened up or the progesterone has thickened up the endometrium This endometrium is nice, rich, thick with nutrients and blood for a possible pregnancy, for a possible implantation of a little embryo. If you don't get pregnant, you don't need all of that tissue and blood. So there's no reason to maintain it. So what happens if you don't get pregnant is the corpus luteum will shrivel and die. no more progesterone will be released. If progesterone is no longer released, then the endometrial lining will not be maintained. What happens is actually the blood vessels that feed into the endometrium, these blood vessels here, will pinch off or vasoconstrict, which will prevent any nutrients and oxygen from getting into the endometrial tissue. If you're not giving a tissue oxygen and nutrients, then the endometrial lining will nutrients what happens to it? Well it's going to die. So if the tissue dies, which it will, the tissue will begin to shed off and when this tissue slides down and sheds off it will leave behind broken blood vessels and those broken blood vessels will begin to bleed and that is the anatomy of a period. So the uterine cycle, which is found on page 1069, is a description of the repeating series of changes in the endometrium, and it continues from menarche, which is your very first period, to menopause, which can be your last. There are three steps to the uterine cycle, beginning with menses. Menses is when you actually begin the process of bleeding. Menses last anywhere from... from one to seven days. I've never met anyone with a one day period so I don't know where your book gets that from but we'll go with it. One to seven days would be considered normal and in that time women lose anywhere between 1.2 to 1.7 ounces of blood. Now the pain that's associated with menses is that the uterus is contracting and that contracting is the uterus attempting to rid itself of all of the extra tissue and blood that's not needed. will help you to lose that blood and tissue better more efficiently so after menses when all the blood is lost we then have what's called the proliferative phase where we begin to rebuild the endometrium to prepare for a new cycle and then the secretory phase where the endometrium is at its thickest and most ready for implantation. So we can see that in this figure here which is found on page 1069 of your textbook. Here is the uterus going through menses. We can see that the lumen is pretty empty and the endometrial tissue is very thin because we're shedding and shedding it out Here is a picture of the uterus As soon as menses is over, we begin going through proliferation proliferation or the proliferative phase We begin to build up the endometrial tissue again Secretory phase is when the endometrium is at its thickest in preparation for pregnancy and when this phase is over if you don't get pregnant, then we cycle back around and have a period and begin the process again. The vagina's major functions are passageway for elimination of menstrual fluid, receiving the penis during sexual intercourse, and forming the inferior portion of the birth canal. The external genitalia of the female includes the vulva, which the vulva is the word that describes all these things combined, the vestibule, the labia minora and majora, periurethral glands, clitoris, and the lesser and greater vestibular glands. So we'll go back to our original picture to look at some of those things. Okay, so we just finished talking about the uterus, the cervix, fallopian tube, ovary, and then we have the vaginal canal. Here's the clitoris. Then we have the paraurethral glands on either side of the urethra. And then we have the greater vestibular gland, which produces lubrication during intercourse. Here we have the labium minus. and then the labium magus. And it's labium minora when you're talking about both of them and the labium majora when you're talking about both of them. But labium minus and labium magus when you're just referring to one. Memory glands include the pectoral fat pad and a nipple surrounded by the areola and they function in lactation under the reproductive hormones, under control of the reproductive hormones, which you can see a picture of. this on page 1072 we will not talk about lactation until we get to pregnancy so that will be covered in chapter 29 but in this picture here we can see some of the major structures of the mammary gland we have course the lactiferous ducts, the lobes of the mammary gland where milk is produced. We have the pectoralis major here, adipose tissue, the areola, and the nipple. Hormones of the female reproductive cycle control the reproductive cycle and coordinate the ovarian and uterine cycles. Key hormones of the female reproductive system include FSH which will stimulate follicular development, LH that helps with ovulation, estrogen has multiple functions like secondary sex characteristics, and progesterone which can stimulate endometrial growth and secretion. The physiology of sexual intercourse. Now I think by the time we all get to the age that we are here we should know how this works so we're going to go through it pretty quickly. Male sexual function. Arousal leads to erection, which can only occur under parasympathetic outflow, which means that a man has to be relaxed in order to get an erection. This is also the cause of many of the nocturnal erections or erections that happen throughout the night. A man has to be relaxed, meaning that if you are in sympathetic fight or flight mindset, as though you're being chased by an axe murder or something really extreme, like that and you can get an erection then that's just extremely creepy and weird so that should not be possible parasympathetic outflow means that the man must be relaxed in the rest and digest phase once erection occurs emission and ejaculation then happens under sympathetic stimulation because once sex begins of course that is an excitable phase so that would change from parasympathetic to sympathetic Once sex occurs, then semen will be pushed towards the external urethral opening, and detumescence is when the erection goes away, which is controlled by another charge of the sympathetic nervous system. In females, it's similar. Arousal causes clitoral erection, vaginal surfaces are moistened, and parasympathetic... Parasympathetic stimulation causes engorgement of blood vessels in the nipples This can actually cause what some people refer to as sex flush, which is a reddening of the chest Aging Menopause is the time that ovulation and menstruation tend to cease which is typically around the age of 45 to 55 And it's accompanied by a rise in some hormones and a decline in others. It's sort of a screwy time for hormones which can cause a lot of symptoms like hot flashes and mood swings and very emotional moments. Typically there's a decline in estrogen and progesterone, but a rise in FSH and LH. And men have their own menopause. It's called the male climacteric. And this is when levels of testosterone begin to decline and FSH and LH levels rise, but there is a gradual reduction in sexual activity. This concludes chapter 28.

Gamete of course being a sex cell whether that's egg or sperm. So the gametes are going to be produced then stored. nourished by the reproductive system, and finally transported. Fertilization is defined as the fusion of a male and female gamete together to form what is called a zygote. Now we should remember that a human cell is made up of 46 chromosomes.

So a male sperm will carry 23 of the father's genes, and the female egg will carry 23 of the mother's genes. So when those two gametes combine, we have a 46 chromosome zygote, which will be exactly half mom and dad. Now that's about all we're going to say for fertilization.

right now as we'll save that for chapter 29. So the reproductive system is going to include whether in male or female gonads which would be either the testes or the ovaries, ducts which will carry the gametes from the gonads out of the body, and accessory glands and organs that are going to contribute fluids to the reproductive system, and finally the external genitalia. In males, the testes produce spermatozoa. Spermatozoa is a fancy word for a mature sperm cell. Men make about a half a billion every single day of their lives. average.

There's a high end and a low end to that. And they're expelled from the body in semen during ejaculation. It's important to know that the sperm cells are the actual tadpole-like cells in the semen, which is the fluid that surrounds and nourishes those cells. So when we say semen, it only refers to just the fluid part of ejaculate.

Females, the ovaries produce oocytes. An oocyte is an immature egg and it's also important to know about the difference between female and male is that males produce sperm every day once they release puberty. the way through their entire lives whereas females only make eggs before they're born so a baby girl on her very first day of life already has all the eggs she will ever have in her entire lifetime she will never make new ones and those eggs will lie dormant until she reaches puberty when they will begin releasing one a month throughout her reproductive years but girls do not make new eggs once they're are born.

They only have the ones they're born with. Once those eggs are released during each month's ovulation, the egg will travel along the uterine or fallopian tube toward the uterus and the vagina connects the uterus with the exterior of the body. So for females we're going to get into them in detail in the last half of the chapter.

So we'll start out with males first. The reproductive system of the male begins by talking about the pathway of sperm. And in your notes that I've given you, on your outline, you have a little acronym, 7UP. And 7UP, each one of those letters, stands for a part of the pathway of sperm production and release.

So let's start with the S, and we'll fill that in with seminiferous tubules. Seminiferous tubules are located inside the testicle In this picture, we're looking at a mid-sagittal section of the male pelvis We can't actually see inside of the testicle in this picture The seminiferous tubules are tiny little coiled up tubes that are located inside the testicle Those little tubes are where sperm production first takes place are formed in the seminiferous tubules, they then will move to the E part of 7up, which is the epididymis. And that's what this is right here.

This structure that hangs on to the back of the testicle. Now of course remember we're only looking at half the picture. There is one testy here and one epididymis, but we know that there are two testicles, so that means there are also two epididymis.

Okay, so the epididymis. is on the back of the testicle and then once the sperm are produced and moved to the epididymis they will then enter what's called the vas deferens which is the V in 7up the V in 7up now your book has has started adopting this new term ductus deferens I want you to know that ductus deferens is the same thing as the vas deferens Vast deferens, but I like to use vast deferens because it fits in our 7up So the vast deferens is a series of tubes. There's one for each testicle so we can see one here It's a tube that goes all the way around the back of the bladder.

Okay, of course, here's the bladder so we're going all the way around the back of the bladder and Once we get through the vast deferens the vast deferens then Urethra Urethra Out through the penis One more time One more time Testicle Epididymis Vast deferens All the way around Back of the bladder Ejaculatory duct Urethra Out through the penis That seems like quite a loop And that seems like quite a loop It takes several weeks for sperm to fully mature enough to where they are able to fertilize. That long pathway gives sperm time to become mature before they are released. Now that we know the pathway of spermatozoa, which again are mature sperm cells, we then have to talk about the accessory organs. groups of accessory organs we have the seminal vesicles the seminal vesicles the prostate gland and the bulbourethral gland so we'll take a look at where those three are and then a little bit later we'll talk about what they secrete the scrotal sac encloses the testes and of course the external genitalia being the penis so in this picture here we can see the prostate gland which we learned about in urinary system is right below the bladder then we have the seminal vesicles of which there are two on the back of the bladder here and the bulbourethral gland which is located right there okay so those three accessory glands So we'll first talk about the descent of the testes.

When a baby fetus is forming, a baby boy, his testicles actually start up very high in his abdomen up near the kidneys, which is certainly a long time. from where they should be so as fetal development continues the testes should descend into the scrotal sac so we'll look at a picture of how this happens now this is a two month old fetus This is not a 2 month old infant, this is a 2 month fetus. Very tiny, maybe the size of a peanut. This is the pelvis that you're looking at here.

The umbilical cord. There's the testicle way up near the kidney. There's the scrotal sac way down here.

There's a cord that attaches the testicle down into the scrotal sac. And that cord has a very ridiculous name, gubernaculum. testy and that name as bizarre as it is is the cord that actually attaches the testicle to the scrotal sac now when you look at a picture like this it's sort of It looks as though maybe that gubernaculum testi will shrink and kind of reel in the testicle to the correct location.

But that actually is not at all what takes place. The gubernaculum testi never changes in... length, but the baby's pelvis enlarges and lengthens, so this will allow the testicle to end up in the right place at the end of fetal development.

We know this because we can see at two months, this right here is the measurement. of the length of the gubernaculum testes, five millimeters, which is quite tiny. Here we are at three months fetal development.

The testicle is much lower. The gubernaculum testes still measures five millimeters. The baby's body has just gotten bigger.

And at birth, right before the baby is delivered, we still have a gubernaculum testes and it's still five millimeters in length, but the baby's pelvis has gotten much larger. and has lengthened which has allowed the testicle to end up in the right place by the time birth occurs this is a frontal view of the same process and we can see how the gonads or testicles are way up near the kidneys but as the months pass the testicles begin to descend descend and descend until at birth they should be located within the scrotal sac So there is a very important set of muscles in the scrotal sac and the first is the dardos muscle The dardos muscle wrinkles the scrotal sac And what it's basically doing Is the wrinkles in the scrotal? sac that muscle bunches up the skin and so it's basically a storage area for the skin that's not used when there is not an erection when there is an erection there is a need for more skin so the skin is not in use the dardos muscle wrinkles it and holds it bunches it up on the scrotal sac the cremaster muscle is a very important muscle because it's it's a skeletal muscle and it actually pulls the scrotal sac close to the body in response to temperature the testicles need to be at least two degrees Fahrenheit lower than body temperature in order to have healthy sperm count so if It is extremely cold. The Cremaster muscle will pull the scrotal sac close to the body to keep it warm.

If it's very warm, the Cremaster muscle relaxes and allows the scrotal sac to drop away from the body, which keeps them from overheating. So that muscle on its own will help to determine whether or not the scrotal sac needs to be closer or further away from the body based on temperature. Thank you.

The testicles are also surrounded by a special membrane called the tunica albuginea. The tunica albuginea is a fibrous membrane that surrounds the testicle and divides the testicle into lobules. And the lobules are separated by septa.

Okay, so we'll look at a picture of this so it'll make a little bit more sense. Now before we look at the testicle on its own, we can look at the musculature of the scrotal sac in this picture here. Here we can see the testicle and epididymis are cut deeper. On this side, the testicle is surrounded by a muscle, which is colored in a red. That's the cremaster muscle.

Then we have the skin, and right under the skin is the dardos muscle. The one that wrinkles the scrotal sac when the skin is not in use. Cremaster, dardos, and skin.

than the actual skin. Okay, so if we look at this picture of the testicle, this is a picture of the testicle's sliced transverse. Okay, so we can see inside each scrotal cavity.

So here's the actual testicle, and we can see some skin. The dark area is the scrotal cavity Then we have the cremaster muscle The dardos muscle and the skin If we focus on the testicles We can see that the testicle is surrounded by a membrane called the tunica albuginea and that tunica albuginea Actually pushes into the testicle and divides the testicle into lobules And you can see almost like the segment of an orange in a way little triangular sections each one of these lobules or triangular sections is filled with seminiferous tubules which was the S in our 7up that we talked about when we talked about sperm production those little coil up tubes are where sperm production actually takes place okay so we have the S for 7up the first S seminiferous tubules located in the lobules of the testicle So in the seminiferous tubules is where sperm production takes place Not only do we have sperm production happening in the testicles, but also sex hormones are produced like testosterone Once the sperm are produced they'll pass through what's called the reet testes into the efferent ductules finally to the epididymis so if we go back to this picture here we can see the pathway so we know that that the first S is seminiferous tubule which is what this is here so once the sperm is produced it will then be pushed into this area which is called the rete testes the rete testes will then pass the sperm into the efferent ductules and then the epididymis okay so again seminiferous tubules rete testes efferent ductules into the epididymis, which is the first E in 7UP. So we're going to look a little closer at how this actually happens, and the process is called spermatogenesis, or the creation of sperm. And of course it begins in the seminiferous tubules, and it starts with stem cells called spermatogonia. Spermatogonia are stem cells that are constantly dividing.

They're constantly making new sperm. sperm cells. The spermatogonia will divide and create new cells and those new cells will continue to change until they become mature sperm cells.

So we'll take a look at that process. Along with the spermatogonia we also have some special cells called sustentacular cells which are going to sustain and promote the development of sperm, sort of nourish them as they are developing. So let's take a closer look at spermatogenesis. We'll look inside the seminiferous tubule and you can see this on page 1047 of your textbook.

This is a microscopic view of the seminiferous tubules that have been sliced. So we're taking one seminiferous tubule and we're blowing up the one seminiferous tubule to see how sperm are produced. And in this picture here, we can see that the sperm are being produced in the wall of the seminiferous tubule.

So what I want to do now is take this one little piece of wall right in here, and I want to blow that up a little bit closer so we can see what's going on in these cells. Okay, so in the seminiferous tubule we have two areas we need to be aware of This is the outside of the seminiferous tubule right here And this is the lumen which remember is the hollow inside of any organ so this This is the hollow inside of the tube and this is the outside of the tube. Down here at the very bottom is the spermatogonia, which are the stem cells.

The ones that make new sperm. All down here is spermatogonia. Spermatogonia will divide to produce primary spermatocytes.

Primary spermatocytes. Primary spermatocytes will become secondary spermatocytes, which are these guys here. Secondary spermatocytes become spermatids, which are these. And spermatids become spermatozoa.

which are mature sperm cells. So we started at spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids, and then spermatazoa which are the mature sperm cells. But how do we go from spermatid to spermatazoa? As you can see these guys don't look anything like these.

There's no tail, there's no neck, there's no head. So there's got to be a lot of change that's going on between here and here. So we're going to look at that next So each spermatozoon and spermatozoa The spermatozoan is one spermatozoa, one mature sperm cell.

So each mature sperm cell has three parts. A head, a middle piece, and a tail. The head contains... This is dad's DNA.

23 of the father's chromosomes packed into the nucleus. The middle piece contains mitochondria that are going to power the tail. We know sperm are very active. They use their little tails to swim and that's how they try to get to the egg so the mitochondria need to be strong producing lots of ATP for the tail to move and the tail is the only flagella in the human body Alright so in this picture, which is figure 28 28 this is found on page 10 51 of your textbook and it shows how we we go from spermatid to spermatozoa to mature sperm cell. The main reason that there's such a big change is not only that we need the sperm to be mobile so that they can move through the female's body to get to the egg, but also sperm need to be lightweight and very small.

They have a long trip ahead and they don't need to be carrying around a lot of extra baggage. When we start at this spermatid, you can see that the sperm The sperm has a lot of organelles and cytoplasm and it has no way to move. There's no flagella.

As time goes through the sperm to the spermatozoa, we're going to start whittling down the body plan of the sperm. We're going to start shedding off cytoplasm, which will include organelles we don't need. We'll continue to shed as...

As we develop a tail, and once we've shed off all the extra organelles and all the extra cytoplasm, we're left with a mature sperm cell at the end of this process. And the mature sperm cell, again, has a head, which contains 23 of dad's chromosomes, a neck piece, which has mitochondria that will make energy for the tail. But there are no other organelles involved. This sperm there's no Golgi.

There's no er. There's no ribosomes. There's none of that stuff all of those things Will be supplied by the mother's egg the sperm just needs to carry dad's chromosomes to the egg when the time comes Alright, so once the testes produce mature sperm cells, the sperm will enter the first E in 7UP, which is epididymis.

The epididymis is an elongated tube with a head. It's going to be used to monitor and adjust the fluid in the seminiferous tubule. It's going to store and protect the sperm cells and also give them time to to mature. Once the sperm cells move into the epididymis, they're going to spend about two weeks getting through the epididymis, which is a maze of tubes.

And that two-week period will allow the sperm to start maturing even further to become prepared for when they might possibly enter the female's body. So this is a picture of the testicle and epididymis on page 1052. of your textbook. Here's the testicle course and the outside of it is covered with the membrane the tunica albuginea.

Each one of these is a lobule that contains seminiferous tubules. The seminiferous tubules will produce sperm and push them into the rete testes where they go through the efferent ductules into the epididymis which is this area here. here on the back of the testicle.

So once the sperm enter the epididymis, they'll take two weeks just to get through this one little epididymis before they enter the vas deferens, which is the V and seven up. The vas deferens begins at the epididymis and passes through the inguinal canal and enlarges to form the ampulla on the back of the bladder. The ejaculatory duct at the base of the seminal vesicle and the ampulla will join together and form the urethra. Okay, so we're going to go... Fat so that I can show you the vast deference and how it joins together with the seminal vesicle into the ejaculatory duct and we'll take two views of this.

So here comes the vas deferens around the back and it joins with the seminal vesicle, which we haven't really talked about yet. This is a gland and the ejaculatory duct and then feeds into the urethra and out. So let's take a view of the back of this right here so we can see it a little bit more clearly.

Okay, so this picture is on page 1053 of your textbook and it shows how all of these tubes join together. So we have here the vas deferens from one side and the vas deferens from the other testicle. The vas deferens enlarges on both sides to form what's called an ampulla. It's a swollen portion of the vas deferens. The two swollen ampulla join together With the seminal vesicle glands, all four join together to form the ejaculatory duct which runs right through the prostate.

The ejaculatory duct then feeds into the urethra which will exit the body. So the urethra has three regions, the prostatic, membranous, and penile. So if we look at all three of those regions, we can see why they each have their names. The prostatic urethra of course is going through the prostate the membranous region is In between the prostate and the penis and then this is the penile urethra so penile membranous prostatic of the total volume of semen.

The seminal vesicle fluid contains three major things – fructose , prostaglandin, and fibrinogen. Fructose or the sugar in this secretion is going to give the sperm mitochondria the sugar they need to produce energy or ATP The prostaglandin will cause contractions in the male and female reproductive tracts the prostaglandin will cause spasming of the male reproductive tract helping to get rid of all the semen and once the prostaglandin actually enters the female's body it causes her vaginal canal to contract which will pull more semen in that the thought is to increase the chance of pregnancy and fibrinogen causes a temporary clot of semen in the vagina so the semen thickens up when it enters the vagina because of fibrinogen which helps more of its stay in the vaginal canal less of it can run out The prostate gland secretes slightly acidic prostate fluid and it contributes about 20 to 30 percent of the secretion. And the fluid is slightly acidic which the prostate, it's not fully understated. all the functions that it may have but one thing that we do know is that the prostate is likely one of the reasons that men are less likely to develop urinary tract infections because the prostate acidic fluid can inhibit bacterial growth.

The bulbourethral glands, which secrete around 10% of the semen, is an alkaline mucus with lubricating properties. Bulbourethral fluid is what's often referred to as pre-ejaculatory fluid. It's kind of a clear mucus and the bulbourethral fluid, what it does is it actually coats the inside of the bulbourethral glands. So, it's a of the urethra before ejaculation and the idea is to lubricate the penis but to also neutralize urinary acids because remember men use the urethra for urination and also ejaculation so if there is a urinary acid residue in urethra it could potentially harm the sperm when the sperm move through the urethra during ejaculation. So the vulvo urethral glands are going to neutralize the acid to create a safe passageway for the sperm when they actually come through.

So the typical ejaculate is only 2 to 5 milliliters of fluid and it contains between 20 to 100 million sperm per milliliter so that could be on the high end 500 sperm per ejaculate. Now whenever we call a man sterile, a lot of times people think that he has no sperm in his semen, but that's not actually true at all. It just means that the sperm count is so low that the chance of any sperm actually making it as far as the egg are very slim. And we'll talk about why that is when we get into reproduction in chapter 29. So overall, seminal fluid is a distinct ionic and nutritive glandular secretion.

Overall semen would be considered extremely basic. The reason for it, and when I say basic I don't mean simple, I mean basic on the pH scale. It's considered basic because the female's body is terribly acidic.

So without the coating of semen around the cells, the female's acidic vaginal canal would likely kill many of the sperm and make it less likely for pregnancy to occur. The male external genitalia consists of the scrotum and the penis, and the skin overlying the penis resembles the scrotum. The penis contains three masses of erectile tissue, two corpora cavernosa, and one corpus spongiosum.

The dilation of that erectile tissue is what produces an erection. So if you look on page 1055, we can see how the spongy and cavernosa tissue is located inside the penis. So here we have these purple cylinders. are the corpora cavernosa.

Each one surrounds an artery and below that we have the corpus spongiosum which surrounds the urethra. So these three cylinders of erectile tissue, if we were to take a transverse section and look at that, that's what this is. We have corpora cavernosa, another corpora cavernosa, each surrounding an artery and then below that is the corpus spongiosum.

surrounding the urethra. When these spongy tissues are engorged with blood this is what creates an erection. Male reproductive hormones.

First we have FSH which is of course follicle stimulating hormone and its job is to target sustentacular cells to promote spermatogenesis. LH will cause secretion of testosterone and other androgens Gonadotropin releasing hormone is going to also help with sperm production And testosterone is the most important androgen, not only because it assists in sperm production, but it also is going to give men their secondary and primary sex characteristics. Okay, so we'll now move into the reproductive system of the female, which is the second half of chapter 28, and it begins on page 1060. And if you recall... Believe in a couple of other chapters or maybe one other chapter. I showed you some ads from the 30s Just to show you how far things have come and this one says you may think she's just your gal But she may be everyone's pal so Prophylaxis prevents venereal disease nice way to say wear a condom, which is kind of forward for that time And then this one is pretty awesome This one shows how a woman this woman here is held in a web of indifference Her husband does not care about her.

He's not interested in her and the reason is not because of anything significant really but Because she hasn't douched with her Lysol Because apparently Lysol used to be the doctor's number one douching agent I cannot imagine how painful that would be but apparently didn't you could use it to disinfect your floors and also After Lysol, her husband is extremely interested in her again. Many doctors recommend Lysol for feminine hygiene. for six reasons and it just gives us one. It's much safer it says than homemade douching solutions.

For feminine hygiene use Lysol. That is extremely ridiculous and there's no gynecologist in this time period that would ever suggest you use Lysol. Okay so the main organs of the female reproductive system are the ovaries, the uterine tubes, which used to be called fallopian tubes, tube so I will probably always say fallopian tube but your book is going to refer to it as a uterine tube the uterus and then of course the vagina or vaginal canal the ovaries uterine tubes and uterus are enclosed within a broad ligament and the mesovarium is going to support and stabilize the ovaries so we'll look in a second at some of those ligaments and mesovar But first we'll take a look at the basic female anatomy. So this is a mid sagittal section through the female reproductive tract found on page 1060 and we can see here we got the the pubic bone there the bladder and the urethra and Then here of course, we're only looking at half the picture.

We've got a fallopian tube ovary pear-shaped organs figure This is the uterus and right here at the bottom of the uterus is the cervix and then the vaginal canal. So we're going to look at these in steps. The ovaries are held in position by ovarian and suspensory ligaments and blood vessels enter the ovary at what's called the ovarian hillus.

And we've used that word many times at this point, so you probably remember that that's just where blood vessels and nerves enter an organ. And tunica albuginea, just like in the male reproductive system, is a membrane that covers the ovary. Alright, so this picture is found on page 1061 of your textbook.

And it is a picture of the uterus, which again is a pear-shaped organ. The uterus is almost entirely muscle. It's just a big, thick muscle. Vaginal canal and cervix Cervical opening is where childbirth must occur It has to get to be 10 centimeters open, which is extremely wide in comparison to what it normally is then up here we have fallopian tube on the left and fallopian tube on the right and each fallopian tube is aligned with an ovary on both sides and of course the ovary is where we're going to find the eggs that were already created when the female was first born you Here we have an ovarian ligament. This is going to attach the ovary to uterus.

And this thing that looks like wings is the broad ligament on either side. And the broad ligament is going to anchor the uterus into the abdomen or into the pelvis. And the main reason for this is the uterus does a lot of moving around. Even during your menstrual cycle, the uterus is going to contract to help rid your uterus of the blood that it doesn't need since pregnancy did not occur. When the uterus does become fertilized, the uterus has to grow many times its size.

We'll have a baby in there doing gymnastics. Because of that, we have to have this ligament to hold the uterus in place. To give it a little bit of anchorage as it goes through all these major changes.

So, oogenesis. Oogenesis is the production of the egg. And we already alluded to that oogenesis occurs before a woman is ever born. So, every newborn girl already has all the eggs she'll ever need for her entire life and she'll never make new ones.

It's often said, it doesn't sound very good, but it actually is good, that for men it's quantity not quality. And what that means is that men produce just ridiculous amounts of money. They have had ridiculous amounts of sperm their entire life.

And they're produced in such mass production that every single one of them can't be perfect. So even the most healthy of men do have a lot of sperm. have some sperm that are not so great. Some that swim in circles or have big big tails or tails that double tails that end up swimming and bumping into things and those are sperm of course we don't want to make it. But that being the case many of those sperm will die off as they begin to trek to the egg.

So there's not not every sperm is top quality but for women because we only make eggs once in our life we have to take care that those eggs are as perfect as possible. So for women it's about quality, not quantity. We have a fraction of the amount of sex cells that men have, but ours have to be perfect because we've got such a precious few. So once we have formed our eggs, which is before birth, then those eggs will lie dormant until we reach puberty.

Once a girl reaches puberty, she will begin to release one egg a month in what we call a ovulation. This is going to refer to our next thing which is the ovarian cycle. The ovarian cycle is two phases. We have the follicular phase which is pre ovulation and the luteal phase which is post ovulation. The follicular phase pre ovulation let's first remind ourselves or if you've never heard this before.

The females reproductive cycle lasts approximately 28 days. 28 days on average. So thinking about the average female, pre-ovulation would be half of that.

The first half. So the first 2 weeks or the first 14 days. So day 1 up to about day 14 is pre-ovulation.

Ludio- Day 14 is post ovulation Day 14 is when we would expect ovulation So the ovarian cycle is going to cover some steps the formation of the primary secondary and tertiary follicles then we have ovulation and after that Formation and Degeneration of the Corpus Luteum Degradation of the Corpus Luteum This is on page 1063 of your textbook and what we're doing here is we're actually looking at the cortex of the ovary so the ovary has two parts it has this outside perimeter which is the cortex and the inside is the medulla so in the cortex of the ovary if we take one little chunk and we blow it up this is the cortex of the ovary okay this one little picture and in the cortex we can see some little structures here the These are oocytes. Oocyte being immature eggs. These are immature eggs.

These are the eggs we've had since the day we were born, if you're female. These are called primordial follicles. Now the first thing we need to do is write down what a follicle is. A follicle is a secretory sac or gland. A secretory sac or gland.

Each follicle has a secretory sac. Each oocyte is surrounded by a follicle. The follicle is a cushiony, pillowy sac that surrounds, protects, and nourishes the egg.

Each one of these oocytes has around it a follicle. This is called primordial follicle because primordial means that it's been there since the beginning of your time So since the day we were born we've had those eggs So this would be day one Day 1 of the 28 day cycle There is going to be a spike in hormone around day 1 and that hormone will be FSH or Follicle Stimulating Hormone which makes sense because we want to stimulate those primordial follicles so follicle stimulating hormone would be perfect for that job so we'll have a spike in FSH which will cause FSH and FSH will cause FSH and FSH will cause FSH and FSH will cause FSH and FSH and FSH and FSH which will cause FSH several follicles to become activated. Okay, so this is an example of what could happen. So here we have two follicles that have become activated and each follicle contains an oocyte. Alright, notice that the follicles are primary follicles and the oocytes are primary oocytes.

Now the oocytes and follicles are not going to mature at the same time. same rate so we need to be careful to note when they're primary, when they're secondary, when they're tertiary. So I'm going to be sure to point that out as we go down the line. So here we are at the beginning of the cycle day one and we're going to have a spike in FSH.

FSH will cause the stimulation of some follicles. In this example we have two. Each follicle contains an oocyte. So right now we have primary follicles.

and primary oocytes. You can see the faint outline of the follicle around the oocyte. One of these follicles will be selected to move to the next step.

The other will disintegrate. So it looks as though this one is disintegrated and we're going to move this guy over to the next step. So as time continues on, this particular follicle and oocyte are selected.

to become the secondary follicle. So here we have a secondary follicle, which is a big swollen follicle that's taken on a lot of fluid. And then we have in it the primary oocyte.

Primary oocyte. So the oocyte is still primary, but the follicle is getting bigger and more swollen. And we now call it the secondary follicle. The secondary follicle then enlarges. The egg is huge and has accumulated a ton of fluid and the egg has not changed at all.

The follicle has matured and matured. The egg has not changed at all. The follicle has matured and matured.

The egg has not changed at all. So at this point the tertiary follicle is so large that it will actually create a bulge on the surface of the ovary and That bulge on the surface of the ovary can sometimes cause what we call Ovulation pain if you've ever had any tenderness This is a good time to get your ovaries open for soreness Here we are creeping up on the pelvic region There are two major things One, ovulation But it's also going to cause the primary oocyte to become secondary So we're going to have our first maturation So here we are at ovulation. This is an actual picture of the surface of the ovary with the egg bursting out.

So this is day 14 ovulation. The egg is going to pop out and as that luteinizing hormone caused the egg to mature, we now call the egg... your oocyte secondary.

So on day 14 it becomes secondary and that little oocyte will begin floating down the fallopian tube for a possible chance at pregnancy. So we'll we'll pick up there in just a minute, that as the egg pops out of the ovary and begins to move down the fallopian tube, the egg will leave behind some follicular cells. Those follicular cells will become egg does become fertilized, then the uterus will be ready to accept the egg and to start the development of an embryo. So the corpus luteum will remain in the ovary until it's determined whether or not we're pregnant.

into three areas we have the infundibulum the ampulla and the isthmus infundibulum ampulla and the isthmus and you can see those three regions on page 1066 of your textbook so we're going to take a look at those three regions and I'll point them out for you they're also part of your lab Okay, so uterus here Then we have the fallopian tubes on either side and the ovary So the three regions of the uterine tubes are we have the fifth which are the little finger-like projections on the end of the fallopian tube. The fimbriae are attached to the infundibulum. Then we have the ampulla and the isthmus, which is what's attached to the uterus. Infundibulum, ampulla, isthmus.

The uterus is a very muscular organ that's going to mechanically protect, nutritionally support, and remove waste for the developing embryo and fetus. It's supported by the broad... ligament and three pairs of suspensory ligaments. We looked at the broad ligament. So what this is saying is the uterus is used for nothing other than development of the embryo.

This is a list of some of the major anatomical landmarks, which we will point out here in this next picture, which you can find on page 1067 of your textbook. Okay, in this picture we can see the uterus has been cut open so that we can see the inside details We have here the uterine cavity, which is the hollow inside or lumen of the uterus We have the fundus, which is the Raised top superior portion of the uterus Of course fallopian tube Ovary Broad ligament Then we have down here the internal os of the cervix Cervical canal Exterior portion of the cervix Cervical os Vaginal canal So if we were to do a cross-section through the uterine wall, okay right here, if we were to cut a chunk through here, we would see three layers. The innermost layer, middle layer, and the external layer. This is the endometrium, myometrium or muscle, and then the perimetrium.

So let's go back a little bit and look at that. So the myometrium is the muscular layer and because the uterus is not under our conscious control, it's smooth muscle, the endometrium is the thin inner lining of the uterus that's what changes in thickness to The parametrium is a serosa that covers the outside of the uterus. We can look at those three layers in this picture which is on page 1068 of your textbook.

Here's the lumen of the uterus, the inner layer of the uterus, or the hollow inside. Then we have the endometrium which is the inner layer of the uterus. Uterus layer Myometrium All muscle Perimetrium Outer covering or serosa of the uterus Now we're going to talk about here in a second the uterine cycle which is the menstrual cycle and in order to understand it a lot of times people want to know where does the blood come from And why does that happen?

well, once you've ovulated and The corpus luteum is released that corpus or corpus luteum develops the corpus luteum will begin to release Progesterone which thickens the uterine lining in preparation for pregnancy So you can see here that the progesterone has thickened up or the progesterone has thickened up the endometrium This endometrium is nice, rich, thick with nutrients and blood for a possible pregnancy, for a possible implantation of a little embryo. If you don't get pregnant, you don't need all of that tissue and blood. So there's no reason to maintain it. So what happens if you don't get pregnant is the corpus luteum will shrivel and die.

no more progesterone will be released. If progesterone is no longer released, then the endometrial lining will not be maintained. What happens is actually the blood vessels that feed into the endometrium, these blood vessels here, will pinch off or vasoconstrict, which will prevent any nutrients and oxygen from getting into the endometrial tissue.

If you're not giving a tissue oxygen and nutrients, then the endometrial lining will nutrients what happens to it? Well it's going to die. So if the tissue dies, which it will, the tissue will begin to shed off and when this tissue slides down and sheds off it will leave behind broken blood vessels and those broken blood vessels will begin to bleed and that is the anatomy of a period. So the uterine cycle, which is found on page 1069, is a description of the repeating series of changes in the endometrium, and it continues from menarche, which is your very first period, to menopause, which can be your last.

There are three steps to the uterine cycle, beginning with menses. Menses is when you actually begin the process of bleeding. Menses last anywhere from... from one to seven days.

I've never met anyone with a one day period so I don't know where your book gets that from but we'll go with it. One to seven days would be considered normal and in that time women lose anywhere between 1.2 to 1.7 ounces of blood. Now the pain that's associated with menses is that the uterus is contracting and that contracting is the uterus attempting to rid itself of all of the extra tissue and blood that's not needed.

will help you to lose that blood and tissue better more efficiently so after menses when all the blood is lost we then have what's called the proliferative phase where we begin to rebuild the endometrium to prepare for a new cycle and then the secretory phase where the endometrium is at its thickest and most ready for implantation. So we can see that in this figure here which is found on page 1069 of your textbook. Here is the uterus going through menses.

We can see that the lumen is pretty empty and the endometrial tissue is very thin because we're shedding and shedding it out Here is a picture of the uterus As soon as menses is over, we begin going through proliferation proliferation or the proliferative phase We begin to build up the endometrial tissue again Secretory phase is when the endometrium is at its thickest in preparation for pregnancy and when this phase is over if you don't get pregnant, then we cycle back around and have a period and begin the process again. The vagina's major functions are passageway for elimination of menstrual fluid, receiving the penis during sexual intercourse, and forming the inferior portion of the birth canal. The external genitalia of the female includes the vulva, which the vulva is the word that describes all these things combined, the vestibule, the labia minora and majora, periurethral glands, clitoris, and the lesser and greater vestibular glands.

So we'll go back to our original picture to look at some of those things. Okay, so we just finished talking about the uterus, the cervix, fallopian tube, ovary, and then we have the vaginal canal. Here's the clitoris. Then we have the paraurethral glands on either side of the urethra. And then we have the greater vestibular gland, which produces lubrication during intercourse.

Here we have the labium minus. and then the labium magus. And it's labium minora when you're talking about both of them and the labium majora when you're talking about both of them. But labium minus and labium magus when you're just referring to one.

Memory glands include the pectoral fat pad and a nipple surrounded by the areola and they function in lactation under the reproductive hormones, under control of the reproductive hormones, which you can see a picture of. this on page 1072 we will not talk about lactation until we get to pregnancy so that will be covered in chapter 29 but in this picture here we can see some of the major structures of the mammary gland we have course the lactiferous ducts, the lobes of the mammary gland where milk is produced. We have the pectoralis major here, adipose tissue, the areola, and the nipple. Hormones of the female reproductive cycle control the reproductive cycle and coordinate the ovarian and uterine cycles. Key hormones of the female reproductive system include FSH which will stimulate follicular development, LH that helps with ovulation, estrogen has multiple functions like secondary sex characteristics, and progesterone which can stimulate endometrial growth and secretion.

The physiology of sexual intercourse. Now I think by the time we all get to the age that we are here we should know how this works so we're going to go through it pretty quickly. Male sexual function.

Arousal leads to erection, which can only occur under parasympathetic outflow, which means that a man has to be relaxed in order to get an erection. This is also the cause of many of the nocturnal erections or erections that happen throughout the night. A man has to be relaxed, meaning that if you are in sympathetic fight or flight mindset, as though you're being chased by an axe murder or something really extreme, like that and you can get an erection then that's just extremely creepy and weird so that should not be possible parasympathetic outflow means that the man must be relaxed in the rest and digest phase once erection occurs emission and ejaculation then happens under sympathetic stimulation because once sex begins of course that is an excitable phase so that would change from parasympathetic to sympathetic Once sex occurs, then semen will be pushed towards the external urethral opening, and detumescence is when the erection goes away, which is controlled by another charge of the sympathetic nervous system. In females, it's similar.

Arousal causes clitoral erection, vaginal surfaces are moistened, and parasympathetic... Parasympathetic stimulation causes engorgement of blood vessels in the nipples This can actually cause what some people refer to as sex flush, which is a reddening of the chest Aging Menopause is the time that ovulation and menstruation tend to cease which is typically around the age of 45 to 55 And it's accompanied by a rise in some hormones and a decline in others. It's sort of a screwy time for hormones which can cause a lot of symptoms like hot flashes and mood swings and very emotional moments.

Typically there's a decline in estrogen and progesterone, but a rise in FSH and LH. And men have their own menopause. It's called the male climacteric. And this is when levels of testosterone begin to decline and FSH and LH levels rise, but there is a gradual reduction in sexual activity. This concludes chapter 28.

Transcript for:Overview of Male and Female Reproductive Systems

Transcript for:
Overview of Male and Female Reproductive Systems