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 seminal vesicles. These are 2 glands that lie on the posterior bladder surface. You can see those in this kind of grayish blue color here and here, so I'm going to label those as 1. The seminal glands produce something called seminal fluid, and this accounts for about 70% of semen volume. The seminal fluid makes up the bulk of the 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. 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 the ejaculatory duct. The seminal fluid will essentially provide a transport for the sperm as well as aid in sperm motility. Alright, so that is our summary.
Next, we have the prostate. The prostate is located inferior to the bladder and is a gland that essentially encircles the urethra. We can see the prostate right here. I'm going to label that as 2. The prostate produces something called prostatic secretion and that accounts for approximately 30% of semen volume.
Finally, we have the bulbourethral glands, also known as the Cowper's gland, and these are two glands that are located inferior to the prostate. You can see those here and here. I'm going to label that as 3. These glands produce a thick mucus that will drain into the urethra, and this mucus is going to drain into the urethra usually before ejaculation takes place; it will neutralize traces of acidic urine and will also lubricate the head of the penis or the glans of the penis. This is commonly known as pre-ejaculate fluid. There can also be some of that fluid left over in the urethra when ejaculation takes place. Thus, all of these fluids in combination with sperm will make up semen.
If you're looking at these numbers and wondering how it adds up, since 70% and 30% already make 100%, and what about the mucus? To give you context, these numbers are approximations, but usually, sperm makes up a very small amount of semen. It’s usually approximately between 1% to 5%, and that can vary across males and also vary within the same male across different ejaculations. 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 the next highest percentage will come from the prostate. Alright, those are the male accessory organs, and I'll see you guys in our next video. Bye-bye.