- [Instructor] For this chapter on the human reproductive system, we're looking-- Starting off with the male reproductive system. Now the testes will be the main organ of the male reproductive system. The testes, their main goal? Producing sperm. They're located outside the body though, they're located in the scrotum, which is a sac of skin. This skin, by being outside the body, allows for lower temperature. Now this lower temperature is important because lower temperature helps to produce sperm more efficiently. But the scrotum itself can be either elevated or depressed depending on the temperature. There are smooth muscles just below the skin that can either help to bring the testes and scrotum a little closer to the body or help to move it away from the body. So this means the scrotum and testes have self-regulation of temperature. Now inside the testes, are tons and tons and tons of tiny little ducts called seminiferous tubules. These seminiferous tubules are where the sperm are produced. As you go from the testes, you leave out into the epididymis and then through the ductus deferens. Now the ductus deferens also known as the vas deferens, is what carries the sperm from the testes up into the male body. The ductus deferens, as it transports around, it eventually transports it down to the actual penis, which is where the ejaculatory duct is. So we start with production in the seminiferous tubules, that's where sperm are produced. They are then transported to the epididymis, they're stored here and the epididymis helps to get them ready and motile. They go through the ductus deferens, which could be also called the vas deferens, this is the single tube on each side, that carries the sperm from the epididmyis up into the body and down towards the penis. It then leaves through the ejaculatory duct into the penis. There are also several other glands that are accessory glands. Now these accessory glands will never actually contain sperm, the sperm do not pass through them. Their only job is to help make sure the sperm stay alive and help them exit the body. The first one up is the seminal vesicles. Now these seminal vesicles are where most of the seminal fluid is produced. One of the major important parts is going to be fructose. Fructose is a simple sugar. It's a simple sugar that will provide energy to the sperm as they travel. The prostate gland. Now the prostate gland can actually have the sperm traveling through it in a duct, but the majority of the gland has nothing to do with the actual traveling of sperm. Instead, what it helps to do, is secrete this alkaline fluid. Well this alkaline fluid is meant to raise the pH in the vaginal canal. It's helping to take that acidic nature in the vaginal canal and raise it towards neutral. Trying to protect and keep the sperm alive. You have the bulbourethral gland. The bulbourethral gland is secreting this kind of thick mucus. The mucus is going to be secreted before the actual seminal fluid. The purpose of this lubricating mucus is to help clean out the urethra. Because the urethra in males is used for urine and for seminal fluid. That means you have the waste product with the gametes. So by using the bulbourethral gland, it helps to clear out any of the remnants of the waste that was part of urine. So the sperm that's traveling through are not coming into constant contact with waste products that were in the urine. So the bulbourethral gland, clearing out and cleaning the urethra, and also helping to provide some lubrication for the gland's penis, or the head of the penis. Here we have some diagrams illustrating the male reproductive system. The left-hand view, the one that's letter a there, you can see is a lateral view, you're looking from the side, as if the body was cut in half. On the right, letter b, that's going to be a posterior view. Looking from the backside or the posterior side, toward the male reproductive. So what you see already, just kind of orientate, we have the urinary bladder and ureter, parts of the urinary system. We have the rectum and anus, part of the digestive. We have the vertebral column and pubic symphysis, part of the skeletal system. So all these things are around and intertwined with the reproductive. We'll start with the testes. The testes is the sight of sperm production. They're held outside the body. The epididymis is where the sperm can be stored for a period, held in place. The epididymis is going to be kind of a cap, or covering over part of the testes. Now we've said the testes are external, they're held in place by the scrotum. We then can travel up into the body, on the ductus deferens, or know as the vas deferens. This is what will allow the sperm to be transported into the body cavity. It's then traveling around to the seminal vesicles. The seminal vesicles will add fluid into the sperm. Helping create that seminal fluid. We can then travel down into the ejaculatory duct, which leads through the prostate gland. Part of the prostate gland also helps to add secretions into seminal fluid. We're then down into the bulbourethral gland. Now the bulbourethral gland, if you remember, was meant to secrete a mucus. This mucus is meant to clean and clear out the urethra before the sperm pass through. You then enter the urethra. The urethra goes all the way to the external part of the penis. So it's the last structure before it leaves the body. The penis itself pretty much, as you can see here, is this bluish and purplish coloration. It's not just external. You can see on the lateral side, which is the left-hand view here, that it also goes into the body, to kind of form an anchoring point. All the blue itself is referred to as erectile tissue. The way the erectile tissue works is blood will actually flow into the erectile tissue and fill up an open or a cavernous space, where the blood will not be allowed to leave. So the blood will keep pumping in without going anywhere causing the erectile tissue to fill up.