Anatomy of the Male Reproductive System (Nursing)

00:02 Now, we're going to talk about the structures of the male reproductive system.

00:06 And to clarify, we're just talking about these structures that are related to the testes and that's where we earn the designation male. We're not referring to gender.

00:15 We're referring to the anatomic structures here.

00:19 And this all starts with the gonads.

00:22 Under the development of a Y chromosome, the gonad will develop into a testes and the testes is going to secrete certain hormones such as testosterone and undergo spermatogenesis to produce sperm.

00:37 The absence of a Y chromosome, the gonad will develop into an ovary.

00:42 It will secrete different sex hormones such as estrogen and progesterone and it will undergo oogenesis to produce eggs.

00:52 And it's the union of sperm and egg that will form the zygote.

00:58 So, let's look at some of the structures of the male reproductive system.

01:02 Again, always starting with the gonad. In this case, we have the testes.

01:07 And the structure of the testes are going to feed directly into the closely associated epididymis that's going to sit along the posterior surface of the testes.

01:18 And then, the epididymis is going to be continuous with a very long muscular tube called the vas deferens.

01:25 And that vas deferens is going to reach a prostate to turn into the ejaculatory ducts and eventually, empty into the urethra.

01:35 And so, these are the male reproductive ducts.

01:38 The ducts that are essentially connecting the testes to the urethra.

01:43 In essence to transport sperm being made in the testes to the urethra where it can then be passed out.

01:51 There are also glands associated with these ducts. And starting with this seminal vesicle, we see we have some glands sitting just posterior to the prostate.

02:04 The seminal vesicle is going to join with the vas deferens at the formation of the ejaculatory ducts which will then empty into the urethra whereas the prostate is going to empty into the urethra directly, much like some smaller glands just distal to the prostate called the bulbourethral glands.

02:25 Externally, we see the penis and the scrotum. And again, the scrotum is going to hold the testes and then, it will be connected eventually through the series of male reproductive ducts to the urethra so that will be how sperm is transported from the testes in the scrotum, out through the urethra meatus of the penis.

02:50 Now, let's take a look into the scrotum to see some of the structures that surround the testicle.

02:57 So, deep to the skin, we have two layers of muscle. More superficially, we have a dartos muscle layer.

03:05 And then, deeper, we have a cremaster muscle layer.

03:08 And then, we have a layer of very thin mucous membrane called the tunica vaginalis which has a visceral and parietal layer much like the pleura and the peritoneum.

03:19 And in fact, it's the exact same structures as the pleura and peritoneum and it's actually nothing more than a portion of the peritoneum that has been descended through the pelvis during development to reach the scrotum.

03:34 So, again, we have the ductus deferens which is another name for the vas deferens which is travelling upward from the testes to eventually reach the urethra.

03:45 We also have some other structures that are connecting down towards the testicles as well.

03:51 One is the artery supplying the testes called the testicular artery.

03:56 We also have venous drainage that parallels this artery called the venous or pampiniform plexus.

04:04 Then, we also have nerves.

04:08 And together, these structures are all going down something called the spermatic cord.

04:13 So, the ductus or vas deferens, the vessels and the nerves are all connecting through this cord that's surrounded by muscle.

04:22 If we zoom out, we can see a little bit of the pubic synthesis which is the midline structure connecting the two halves of the pelvic bones.

04:32 We can see the ductus deferens or vas deferens coming up and over and finally, into the pelvic cavity.

04:40 And we see that it's coming over the bladder and it's going to join the glandular portion, the seminal vesicle just posterior to the prostate.

04:53 And so, because they're posterior, let's swing around and take a posterior view of some of these glands.

04:59 So, again, in the middle, the largest structure here is going to be the bladder which is going to have the ureters coming from above from the right and left kidneys.

05:08 We also have generally, in the same area, the ductus or vas deferens and they're very closely associated in this area because they had a very similar embryologic origin way back in development.

05:21 Then, it gets very wide at this point as the ampulla and that's where it's going to join with the seminal glands and pick up seminal fluid.

05:30 So, the vas deferens or ductus deferens is carrying up sperm from the testes and the seminar vesicles or seminal glands are going to add seminal fluid which will have a lot of supporting structures within it.

05:45 Together, they're going to form the ejaculatory ducts that go through the prostate glands to reach the urethra.

05:53 And again, the prostate glands and the smaller bulbourethral glands just posterior to it are going to eventually feed into the urethra directly.

06:05 Here, we have a sagittal cross-section view to see the course of that urethra a little bit better.

06:12 So, we see that that first portion of the urethra has to go through the prostate.

06:18 And that can be a problem if someone has an enlarged prostate or BPH, benign prostatic hypertrophy, something that's very, very common in older men.

06:31 And because of this enlargement, it will compress the urethra and make it hard to urinate.

06:37 And that can cause problems with the bladder as well causing it to enlarge.

06:43 So, look at the urethra in a little bit greater detail.

06:46 So, we have the bladder and the first part of the urethra as we just mentioned, has to go through the prostate.

06:53 So, we actually call that portion the prostatic urethra.

06:57 Then, there's a very small portion around that area, the bulbourethral glands and some surrounding structures called the membranous urethra.

07:07 And as you can see, it takes a very sharp turn into the longest portion called the spongy urethra that's going through the penis.

07:15 And eventually, the external orifice or urethral meatus.

07:21 And this is something to keep in mind during the process of urinary catheterization.

07:26 This turn in addition to the overall length compared to the female urethra makes catheterization somewhat more challenging and difficult than a short straight tube because it will have to make this turn here at the area of the membranous urethra.

07:45 So, let's look at the penis a little bit. So, in the distal portion, we have the glans penis and that's where we have the urethral opening or meatus where urine and sperm will pass through eventually.

07:58 Then, the majority will be composed of the body and then, the deepest internal part will be called the root of the penis where it'll connect with the membranous urethra and the prosthetic urethra, eventually, going up into the bladder.

08:13 If we were to look at a cross-section of the body of the penis, we can again find the urethra going through it, the spongy urethra.

08:21 And when we see that it's called the spongy urethra because it's surrounded by this portion of the penis called the corpus spongiosum or the spongy body.

08:31 But superiorly, we see there's two larger bodies or corpora called the corpora cavernosa.

08:41 And it's these corpora cavernosa that are actually involved with erection.

08:47 So, under autonomic or involuntary nervous system control, these blood vessels in here can dilate and the venous drainage of the area can become impaired.

08:59 And that can increase the blood flow in this area and that's essentially what causes the process of an erection.