Anatomy of the Male Reproductive System - Video Tutorials & Practice Problems
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1
concept
The Scrotum
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Okay. So we're gonna begin our section on male reproductive anatomy by talking about the scrotum. So the scrotum is an external sac that contains the testes. So the scrotum hangs outside of the abdominopelvic cavity right around the root of the penis and this allows it to provide the ideal temperature for sperm production, which is approximately 93 to 96 degrees. So a bit cooler than the human body, And 2 muscles play an important role in maintaining that. So the cremaster and the giardos muscles We'll be working together to adjust the scrotum based on temperature. If we look down at our image here, just to kind of orient you to what you're looking at, correct anatomical position for a penis is a fully erect penis, so that is what we are seeing here, And we are basically inferior to the penis, so lower than it, looking straight up, if that makes sense. So we have, this would be like the bladder right behind the penis right there, and then this structure is the scrotum. So we see we have the testes would be located here and here. So we'll go ahead and label that as a test step. And then you can see we have, this skeletal muscle right there, that is the cremaster muscle. So what that is going to do is basically when it contracts, it will draw the scrotum up closer to the body, closer to the root of the penis, and that will, of course, keep it warmer. It can also contract due to sexual arousal as well, And so it will contract if the scrotum gets too cold and it will relax if the scrotum is getting too hot. And then next to that, we have the dardos muscle, which is a little bit harder to see here, but it's basically this like whitish gray, kind of sheet like muscle right there. The dardos muscle is comprised of smooth muscle and what it does is basically when it contracts, it kind of tightens the scrotum and causes it to wrinkle and that causes the testes to move closer together, which decreases their surface area, which prevents heat loss. So working together, they can provide the ideal temperature for sperm production. So, those are our sperm production. So those are our cremaster and dartos muscles. Our next major structure is the spermatic cord. So the spermatic cord is a connective tissue sheet that will basically contain blood vessels, nerves, as well as the vas deferens, which we will get to in a later video. So if you look at our image here, you can see, the spermatic cord really nicely right there. And over here, you can see what it would look like if we peeled back that cord, and you can see all those blood vessels and nerves running through, where that cord would be. So we'll label that as our spermatic cord. So it's basically just like the sheath that will be encapsulating everything that's coming into the scrotum or leaving the scrotum, basically. Then we have one last structure and that is this structure right here on the midline there, and that is called the septum. And the septum basically just divides the scrotum which creates 2 compartments, one for each testis, of course. Alright. So that is the scrotum, and I'll see you guys in our next video. Bye bye.
2
example
Anatomy of the Male Reproductive System Example 1
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1m
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Okay so what is the primary function of the dardos muscle? So remember the dardos muscle is a sheet of smooth muscle inside the scrotum and when the temperature outside gets cold that muscle will contract and that action will kind of wrinkle the scrotum and pull the testes closer together and that will decrease their surface area and allow them to conserve heat. So our answer is going to be a) the temperature regulation of the testes. So just looking quickly at b and c, the contraction of the vas deferens and to eject sperm from the testes. So both of those are going to happen through smooth muscle contractions of the vas deferens itself. So the, dartos muscle is not really helping with that at all and then c can be a little bit tricky. It says relaxation of the scrotum and the dardos muscle, of course, can relax just like any other muscle. However, its main function is not to relax. Its function is to help regulate the temperature within the scrotum so our answer here is going to be a.
3
concept
The Testes
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2m
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this video, we're gonna be talking about the anatomy of the testes. Now the testes are paired organs that are enclosed within the scrotum, and these, of course, are the primary sex organs for males or the gonads for males and they're gonna be producing the male reproductive cells which, of course, are sperm. So within each testis, there are 4 major regions that we need to know and these will basically just be a series of tubes and ducts that sperm are going to be moving through. So first up are the seminiferous tubules. So these are tightly coiled tubules. They are highly, highly convoluted. You can see those here in purple, and this is where sperm are actually being produced. And I always remember that because to me, seminiferous just sounds kinda like semen, and when I think of semen, I think of sperm. So that's how I kind of keep in my head that this is is the location where sperm are actually being created. And so sperm are gonna be produced here, but they're not gonna mature here. So the sperm are going to immediately begin to move out, so the immature sperm are going to go out of these purple seminiferous tubules and they're going to enter the straight tubules. And you can see those here in green and they are literally just much more straight and much less convoluted compared to those seminiferous tubules. Those straight tubules will convey firm to the rete testis, So that is our next structure. And so you can see those right here, and this is just a tubular network on the posterior side of the testis that sperm are gonna be passing through as well. And the rete testis will convey sperm to the efferent ductule. Alright. So you can see those efferent or that efferent ductule right there. And, of course, efferent always means exit. Right? So this is the exit duct for sperm that are going to the epididymis, which is the structure right outside of the testis right here. Alright. And that will be the location where sperm are going to be maturing. I know that this is a whole bunch of just tubes and ducks, but to help you remember the journey that sperm are going to be taking, we have a little memory tool here. So you can think of the sentence speedy sperm rush excitedly, where the first, letter of each of those words will match up to the first letter of the anatomy in the order that sperm move through. So they're going to begin with those semaniferous tubules, enter the straight tubules, enter the rete testis, and then enter that efferent ductule which will convey them to the epididymis. Alright, so that is the anatomy of the testes and I'll see you guys in our next video. Bye bye.
4
example
Anatomy of the Male Reproductive System Example 2
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1m
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Okay so we're going to be determining the order in which sperm move through the testis to the epididymis. So there's a whole bunch of tubes in here so you guys remember our little memory tool for how we keep track of the order that this goes. So we think of the phrase speedy, sperm, rush, excitedly and then the first letter is going to be the first letter of each of those tubes. So we are going to begin with our seminiferous tubule, remember, because seminiferous kind of sounds like semen. You think semen, you think sperm, and that is where sperm are going to be produced. So we're going to be starting in our seminiferous tubule and based on that our answer choices are down to b and c. So we have our seminephrine tubule and then we have our straight tubule and then we're going to move into our rete testis and then from there we will go to the efferent ductule. So based on that it looks like our answer is going to be b. So we're going to start producing sperm in that semiferous tubule. The sperm will move into the straight tubule, into the reti testis, into the efferent ductule, and then from there they would move on to the epididymis. And there you have it.
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Problem
Problem
Which of the following structures might be referred to as a ‘sperm factory’?
A
Straight tubules.
B
Seminiferous tubules.
C
Rete testis.
D
Spermatic cord.
6
concept
The Ducts
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2m
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this video, we're gonna be talking about the duct system of the male anatomy, and we're gonna begin with the epididymis. So as I alluded to in our last video, this is the location where sperm mature. And this structure kind of arches over the lateral side of the testis. You can see that nicely here, this purple epididymis is hanging on the side of the testis there. And sperm can actually be stored in this location for several months. So to kind of put everything together, firm are being created in the seminiferous tubules within the testes. They're being conveyed to the straight tubules, to the rete testis, to the efferent ductule, and then into the epididymis where they can then be stored for weeks or even months, and then they can mature during that time as well. So that is the epididymis. Next up, we have the ductus deferens or the vas deferens. I'm gonna mostly be calling it the vas deferens because it's a much more common name, but it is technically called the the deferens. And this is the structure that actually transports sperm during ejaculation. And so it's gonna extend from the epididymis all the way up through the pelvic cavity. You can see nicely here where it's connected to that epididymis, and it will extend all the way through the pelvic cavity, arch over the posterior side of the, bladder, and then it will empty into this little, duct called the ejaculatory duct right there. I'm gonna label that on our image for us. And we're gonna talk about this duct a little bit in our next video, coming up as well. Alright. So that is the vas deferent. So basically, that's gonna be, carrying the sperm once an ejaculation is gonna be taking place. So the sperm the sperm are being stored in the epididymis, and then once an ejaculation is taking place, they will get carried up through this vas deferens. And then finally, we have the urethra, and this is the terminal portion of the male duct system. Okay? And this will be the, structure that is transporting both urine and semen, though not at the same time. So we can see our urethra going here all the way down the penis to the outside world. So we'll label that as the urethra. Alright. So that is the male duct system, and I will see you guys in our next video. Bye bye.
7
example
Anatomy of the Male Reproductive System Example 3
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1m
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Video transcript
Alright. So which structure is responsible for the transport of sperm between the epididymis and the ejaculatory duct? So if you can kind of picture this in your head, remember the epididymis is going to be kind of arching over the lateral side of the testis. So that is located all the way down in the scrotum. So what we are talking about here is the structure that would connect the epididymis all the way down there, kind of come through the pelvic cavity and connect to that ejaculatory duct. And that structure is going to be our vas deferens or the ductus deferens. Right? So our answer is b. So the vas deferens will be extending from the epididymis in the scrotum all the way up through the pelvic cavity. It will kind of arch over the posterior side of the bladder and it will empty into that ejaculatory duct. Looking at these other answer choices, I see seminal glands and seminal glands actually do not contribute to the transport of sperm at all. Those are glands located on the posterior surface of the bladder and they produce seminal fluid So those are definitely out. These straight tubules are located within the testes, so those are going to be basically handling the transport of sperm before they ever get to the epididymis. And then finally, we have the urethra and the urethral will be transporting sperm after the ejaculatory duct. So we'll be ejaculating, into the urethra and then, of course, to the exterior world. So our answer here is b, the vast deferens will be transporting sperm between the epididymis and the ejaculatory duct.
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Problem
Problem
What is the primary function of the epididymis?
A
Production of sperm.
B
Secretion of seminal fluid.
C
Storage and maturation of sperm.
D
Anchor the testis to the cremaster muscle.
9
concept
Accessory Organs
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3m
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In this video we're going to be talking about the male accessory organs and we're going to start with the seminal glands, also known as the seminal vesicles. So these are 2 glands that lie on the posterior bladder surface. So you can see those in this kind of grayish blue color here and here, so I'm going to label those as 1. And the seminal glands produce something called seminal fluid and this is going to account for about 70% of semen volume. So the seminal fluid makes up the bulk of semen volume and the seminal fluid will empty into the ejaculatory duct, which you guys remember is right about here, and that is where the sperm and the seminal fluid will mix. So we're going to have sperm coming in from the vas deferens and we'll have seminal fluid coming in from that seminal gland and they will mix right there in that ejaculatory duct. And the seminal fluid will basically provide a transport for the sperm as well as it will aid in sperm motility. Alright, so that is our somnolence. And then we have the prostate. So the prostate is located inferior to the bladder and it is a gland that basically encircles the urethra. Okay. So we can see the prostate right here. I'm going to label that as 2 and the prostate produces something called prostatic secretion and that accounts for approximately 30% of semen volume. And then finally, we have the vulvarousal glands, also known as the Cowper's gland, and these are two glands that are located inferior to the prostate. So you can see those here and here. So I'm going to label that as 3 for us and these produce a thick mucus that will drain into the urethra and that mucus is going to drain into the urethra usually before the ejaculation takes place and what it will do is it will neutralize traces of acidic urine and it will also lubricate the head of the penis or the glans of the penis. So this is commonly known as, like, pre ejaculate fluid. And then there can also be some of that fluid left over in the urethra when ejaculation takes place. And so all of these fluids in combination with sperm will make up semen. And if you're looking at these numbers and you're like, okay, well, like, you know, 70% and 30% already make up a 100, like, how much of this is actually sperm? Like, what about this mucus over here? To give you context, these numbers are approximations, but usually sperm makes up a very small amount of semen. It's usually approximately between, like, 1 5%, and that can vary across males and it can also vary within the same male across different ejaculations. So keep in mind that these are approximations, but what you should know is that the majority of the volume of semen comes from the seminal glands and then the next highest percentage will come from the prostate. Alright, so those are the male accessory organs and I'll see you guys in our next video. Bye bye.
10
example
Anatomy of the Male Reproductive System Example 4
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59s
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Video transcript
Alrighty, so this one is asking us, the majority of the contents of semen come from which of these structures? And that is going to be the seminal glands. Right? Seminole just sounds like semen and seminal glands produce seminal fluid which makes up about 70% of semen volume. Looking quickly at the other answer choices here, we see we have the prostate and the prostate does create prostatic secretion which makes up about 30% of semen volume. So not insignificant by any means, but not the majority either. The epididymis does, of course, store sperm, which contributes to semen volume in that sense, but the epididymis itself is not producing the contents of, of semen at all. And then finally, we have the bulbourethral glands and those do produce a thick mucus that's often secreted before ejaculation takes place and that can get mixed up into the semen but it's not going to be contributing any significant amount to semen volume. So our answer here is c, the seminal glands.
11
concept
The Penis
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5m
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In this video we're going to be talking about the penis. So the penis as you may recall is the male organ of copulation. And that just means that this is going to be the organ that delivers sperm to the female reproductive tract. So we divide the penis into 3 major anatomical regions. First up we have the root or the base of the penis, in the middle we have the body, and then at the tip we have the head, also known as the glans penis. And I will show you that on our image in one moment. Now, the penis is comprised mainly of erectile tissue which is connective tissue and smooth muscle that is filled with vascular spaces. And so during sexual arousal or sexual excitement those vascular spaces can fill with blood which causes the penis to become enlarged and rigid which we call an erection. And then an erection is what allows the penis to act as the organ of copulation. Now, a very fun fact about the penis is that it is actually homologous with the female clitoris. So homologous structures are structures that have common evolutionary or, origins and are composed of similar tissues. So early in embryonic development these would basically be the exact same tissue and then throughout embryonic and fetal development it would become differentiated into a penis for a male fetus or a clitoris for a female fetus. So what we have done here is we have outlined our main homologous structures with this little blue outline there and you will see those in our video on the clitoris as well. So you can see, which structures are direct homologues between those two organs. Alright. So here is our penis and like I mentioned we have the root of the penis here at the base. We have the body of the penis in the middle. That's going to be the majority of the organ. And then we have the head of the penis also known as the gland there at the tip. We're just gonna go through and start, labeling structures starting up at the root with these kind of little wing shaped, triangular structures there at the base and that is called the crus of the penis. So the crus is going to be surrounded by muscles that help to attach the penis to the pelvic floor and that helps to kind of stabilize the organ and give it some integrity. Next up, we have these 2 bulbous structures right here on the root and those are known as the bulbs of the penis. And the bulbs are composed of erectile tissue so they will fill with blood during sexual arousal. And these are also gonna be surrounded by muscles that help to anchor the penis to the pelvic floor. Alright. Moving down here, we have our corpus cavernosa. So the corpus cavernosa, which we have here in this kind of light pink color, sort of on the outside of the penis, These are paired erectile bodies that will extend from the roots basically all the way down through the body of the penis. And cavernosa literally means cavernous. So these have that, like I just mentioned, that characteristic, vascular structure where there's plenty of room for them to become engorged with blood. And when the corpus cavernosa become erect they become extremely rigid. So these are gonna give the, the erection a lot of its kind of, like, structure, and rigidity. So they become quite hard. And then moving down here, we have our corpus spongiosum. So the corpus spongiosum we've drawn here in this kind of, like, magenta ish color right there. And these are paired erectile bodies that surround the urethra. So the urethra is the structure running straight through the center there. And these extend all the way from the root to the glans or the head of the penis. And, actually, the bulb of the penis is made up of the same tissue as that corpus spongiosum. And spongiosum literally means spongy. And so when the corpus spongiosum becomes erect and filled with blood, it actually does not become rigid. It maintains a spongy texture. And that is important because that basically prevents the urethra from closing. So if we were to have tissue like the corpus cavernosa right next to that urethra, when it filled with blood it could shut the urethra and that would prevent ejaculate fluid from leaving the penis which we don't want of course. So the corpus spongiosome stays nice and spongy and soft and that allows the urethra to stay open, but it does add a little bit of compression to that urethra, which actually helps with the velocity of the ejaculate, as it exits the penis. So that is the main difference between the corpus cavernosa and the corpus spongiosum. One becomes very rigid when it's erect, the other one stays kind of spongy and soft. Alright and last but not least, we have our prepuce for the foreskin of the penis and you can see that really nicely right here And this is just a skin that extends around the glans or the head of the penis. Alright. So that is penile anatomy, and I will see you guys in the next one. Bye bye.
12
example
Anatomy of the Male Reproductive System Example 5
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35s
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Video transcript
This question asks us, removal of the prepuce through a surgical procedure is known as what? So keep in mind that prepuce is just a fancy way to say foreskin of the penis and so if we are removing the foreskin that of course would be a circumcision. Looking through our other answer choices here, an orchidectomy would be the removal of the testes, priapism is a disorder of the penis where it maintains prolonged erections in the absence of stimulation, and then a salpingectomy would be the removal of the uterine tube. So our answer here is going to be b, circumcision.
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Problem
Problem
The corpus spongiosum surrounds which structure in the male reproductive system?
A
The urethra.
B
The bulb of the penis.
C
The bulb of the vestibule.
D
The corpus cavernosa.
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