 the fellow's one, we're starting out with male gross anatomy. So the first thing that we want to look at is the fact that men and women, human critters, both have a copulatory organ, they both have gonads, and they both have gametes. And when I give you, I mean, this probably isn't difficult. So when we figure out the male parts, it should be pretty quick for you to figure out the corresponding female parts, but we'll save them for the next lecture. So the copulatory organ for the fellow's, this is the structure that is responsible for, well, maybe we should start backwards. Perhaps we should start with the gametes, which are the cells that are the whole purpose of the reproductive system in the first place. So in the fellow's, the gametes are sperm. And I know you remember from your rockin' early biology days that sperm are single-celled cells. It's about to call them critters. They kind of remind you of critters if you think about it. They're single cells that have half the amount of DNA. So they're haploid cells. And this is all review. By the nature of being haploid, we only have one copy of each chromosome. That's what it means to be haploid. If you think about it, of course it makes complete sense that if you're going to have a haploid cell that has only one copy, we know that all the rest of our cells have two copies of every chromosome. So therefore, we must combine two haploid cells. The ladies have the other haploid cell that is necessary to make a bebe. Now the gonads are organs that are responsible for producing gametes. So the fellas, the gonads that make gametes are the testes. And testes, that's plural. And if it's singular, you are talking about only one testis. Dome mix it up. But the fellas have two testes. They have two gonads and the testes are the site of sperm production. We're going to spend an entire section talking about how sperm are made. And then in order to deliver the sperm, I mean one critter has the sperm and the other critter has the egg. And so there has to be some sort of anatomy that enables the sperm and the egg to come together. Different animals have different strategies of carrying this out. Not everyone has such a copulatory organ as human critters. There are many very interesting capulatory organs out there. So the fellas, their copulatory organ is the penis. And the penis has some pretty incredible anatomy that we get to look at. Let's start by looking at penis anatomy. First of all, penises are... I'll try not to make a commentary on penises. Penises are floppy structures that would be completely ineffective as copulatory organs if they could not change from floppiness to erectness. And so the anatomy of the penis is set up to enable a shift from floppy to erect. That means that the penis is actually composed of, I don't know, pieces of tissue structures that contain erectile tissue. And there's actually like three bands. And that's a terrible word because bands kind of imply like going around this way. They're actually like three columns. Columns. I don't like band. They're three columns of erectile tissue in a male penis. And you can see, I'm going to... Obviously, I'm starting with penile anatomy first. So I'm going to have to draw all over this. You can see my external penis here. It's not my penis. And you can see like kind of a, I don't know, like doesn't it look kind of dotty all around here? This is one of my columns of erectile tissue. And it is called the corpus spongiosum. Corpus is singular. It means body. So this is basically the spongy body. And if I were to draw a line around my corpus spongiosum, you'll see that it actually travels all the way in to the penis like it's the whole, almost the bulk of the penis is corpus spongiosum. And when I say it's a erectile tissue, the structure, it's like it really is spongy. And there's this whole anatomical phenomenal setup whereby blood, during arousal blood, can enter the penis and it can enter this spongy zone. And the vessels that are feeding the blood in are linked to vessels that are draining the blood. However, during arousal when the blood is, keeps getting fed in, blood is fed in faster and the penis like fills up with blood. It like grows in size, which makes sense because there's more blood coming in here because of arousal. That the act of filling it with more blood actually blocks off the exit route. So now the blood is stuck and it, there's a whole bunch of blood in there but it can't get out. And it's not going to be able to get out. That whole thing, that process of forming an erection by filling all this spongy tissue with blood, that's under control of the parasympathetic nervous system. So let's make a note of that over here. Parasympathetic innervation controls erection. Erection happens because the spongy tissue fills with blood and then the actual erection itself blocks off the blood supply to leave so the blood gets stuck there and your erection lasts until somebody else comes into the mix. If parasympathetic nervous system controls an erection, the parasympathetic nervous system controls ejaculation. So the erection will maintain until the sympathetic nervous system takes over and ejaculation takes place. And it will talk about all, like how does ejaculation happen, what is in there, like we'll talk about all those details. But once the sympathetic nervous system takes over, then we no longer have the stimulus that is creating the parasympathetic scene and the blood vessels change and the blood route to get out comes back and so the blood can leave your penis and now your penis is back to being not erected, erectile. No longer erect. Thank you, I got there. Corpus spongiosum, there's only one of these things. It fully surrounds, like it forms a complete call. No, the spongi urethra travels through corpus spongiosum. That's going to help you too. So spongi, that says spongi urethra, travels through it. So if we actually did like a cross section, like if I went whacked off this penis, sorry that was a rather violent image, but if you sliced it, if you did a dissection line and then you looked at the penis, you would actually see the urethra right down the middle of corpus spongiosum. But I told you that there were three columns and there are. This is part of my, one of my other two columns. And in this diagram, we can't actually see both of those and this is called the corpus. And I'm going to do, my other two are called corporeplural cavernosum, caverno, cavernosa, corporecavernosa. And that's plural. We also, if we wanted to say we just have one of them, it's corpus cavernosum. So when you see it, corpus cavernosum, it's the same thing as corporecavernosa is just singular and corporecavernosa is plural. So it reminds us that there are two of these things. If I were to draw a, that section that I was telling you about of the penis where here's my urethra and this is my spongy, I mean corpus spongiosum, then corporecavernosa would kind of look like this. There's two bands that travel down the penis. They function exactly the same. They're filled with blood, they're spongy erectile tissue. More external anatomy. So when you're born with your penis, you actually have a structure called the prepuse that is this little like sock thing. I don't know, it looks something like that. And it's called the foreskin. I already said it was called the prepuse. I don't know of it as the foreskin. And this structure, you can call it prepuse or foreskin. Yeah, you should probably call it prepuse because that's like the anatomy term. But you should also know that it's the foreskin. Yeah. And this is a structure that during circumcision is actually removed from male baby boys. Not everybody has their prepuses removed. All right, I wanted to tell you the structure that your gonads live in. Okay, so these are the testes. That's one testis and the other testis is on the other side. And the testes live inside a little skin bag called the scrotum. And I think this is the bulk of the anatomy. We know that this is the spongy urethra. We know that this is the external urethra orifice. And we know that gametes and urine come out of that opening. All right, let's talk about the ladies.