Description

Complete Overview of Male Genital Organs (Internal & External)

This video provides a comprehensive breakdown of male internal and external genital anatomy, covering structures, histology, functions, and clinical relevance.

1. Internal Genital Organs

Testis

Key Features:

• Male reproductive gland responsible for sperm production.
• Leydig Cells: Produce testosterone.
• Sertoli Cells: Structural support and aid spermatogenesis.

Prenatal Development:

• Originates in the lumbar region.
• Descends and takes abdominal layers, forming scrotal layers.

External Structures:

• Upper Pole (Extremitas Superior).
• Lower Pole (Extremitas Inferior).
• Anterior Border (Margo Anterior).
• Posterior Border (Margo Posterior).
• Lateral Surface (Facies Lateralis).
• Medial Surface (Facies Medialis).

Internal Structures:

• Tunica Albuginea.
• Vascular Layer (Tunica Vasculosa).
• Septa of Testis (Septula Testis).
• Lobules of Testis (Lobuli Testis).
• Seminiferous Tubules (Tubuli Seminiferi Contorti & Recti).
• Rete Testis.
• Efferent Ductules (Ductuli Efferentes Testis).

Epididymis

• Composed of tightly packed tubules; stores sperm.
• Head (Caput Epididymidis), Body (Corpus Epididymidis), Tail (Cauda Epididymidis).

Coverings & Fixation of Testes & Epididymis

• Tunica Vaginalis: Visceral (Epiorchium) & Parietal Layer (Periorchium).
• Fascial Layers: Internal Spermatic Fascia, Cremaster, External Spermatic Fascia.
• Dartos Fascia (Tunica Dartos).

Spermatic Cord (Funiculus Spermaticus)

• Contains Ductus Deferens, Testicular Artery, Pampiniform Plexus, Lymph Vessels.

Ductus Deferens

• Pathway for sperm transport.
• Divided into Scrotal, Funicular, Inguinal, & Pelvic Parts.

Seminal Gland (Glandula Vesiculosa)

• Produces ejaculate fluid.
• Joins ductus deferens to form Ejaculatory Duct.

Prostate (Prostata)

Structure:

• Base & Apex.
• Posterior & Anterior Surfaces.
• Prostatic Urethra.

Histological Zones:

• Peripheral, Central, Transitional, & Anterior Fibromuscular Zones.

Posterior Features:

• Urethral Crest, Seminal Colliculus, Prostatic Utricle (Fetal Remnant).
• Openings of Ejaculatory Ducts.

Bulbo-Urethral Glands (Glandulae Bulbourethrales)

• Empties into the spongy urethra.

Male Urethra (Urethra Masculina)

• Prostatic, Membranous, and Spongy Urethra.

2. External Genital Organs

Penis

External Structures:

• Root (Bulb & Crura).
• Body (Corpora Cavernosa & Corpus Spongiosum).
• Glans Penis (Corona, Collum, Prepuce, Frenulum).

Internal Structures:

• Corpora Cavernosa & Corpus Spongiosum.
• Tunica Albuginea.
• Buck’s Fascia (Deep Fascia of Penis).

Scrotum

• Contains layers derived from abdominal structures: Tunica Vaginalis, Internal & External Spermatic Fasciae, Cremaster Muscle, Dartos Fascia.

3. Clinical Relevance

• Testicular Torsion: Twisting of the spermatic cord leading to ischemia.
• Benign Prostatic Hyperplasia (BPH): Enlargement of the prostate affecting urination.
• Cryptorchidism: Failure of testis to descend.

Sources Used:

• Memorix Anatomy (2nd Edition) – Hudák Radovan, Kachlík David, Volný Ondřej.
• Complete Anatomy by 3D4Medical.
• Biorender.
• Snell, Richard S. (2012). Clinical Anatomy by Regions (9th Edition).
• University notes and lectures.

Transcript

Introduction
0:03
What’s up.
0:04
Let’s go ahead and cover the male genital system.
0:07
We will cover the most important aspect of the male genitals, and hopefully, in the end,
0:12
you’ll have a pretty good understanding about this topic
0:15
Alright.
0:16
The male genital organs are divided into the internal genital organs and the external genital
0:22
organs.
0:23
We’ll cover both of these in detail, And we’ll start with the internal genital
Internal Genital Organs
0:27
organs So the internal genital organs consist of
0:31
the testes, epididymis, ductus deferens, seminal gland, Ejaculatory Duct, Prostate, Male urethra,
0:40
and the bulbourethral glands.
0:43
Alright, let’s follow this arrangement, starting with the testis.
Testis
0:47
Now, of the whole male reproductive system, the primary functional cells the male has
0:54
are Leydig and Sertoli cells.
0:56
And both of them are found in the testes.
1:00
So the testicle or testis is the male reproductive gland or gonad in all animals, not just humans.
1:07
Leydig cells produce testosterone, which is a steroid hormone that binds to intracellular
1:14
receptors and regulates protein synthesis.
1:18
And what that does is it influences the male development and maturation for developing
1:25
muscles, deepening the voice, growing body hair, and promoting the production of red
1:30
blood cells.
1:32
Testosterone also stimulates the Sertoli cells to provide structural support and secrete
1:38
fluid to nourish and support developing sperm cells.
1:43
So that means that testosterone is also essential to maintain spermatogenesis and male fertility.
1:51
And In the absence of testosterone stimulation, spermatogenesis does not proceed.
1:56
It doesn’t happen, basically.
1:58
The testes are located outside the body, right?
2:02
In a pouch called the scrotum.
2:04
During prenatal development, they originate in the lumbar region, near the kidneys, and
2:11
then they descend through the retroperitoneal space and inguinal canal to reach the scrotum.
2:18
As they descend, the layers of the abdominal wall form the layers of the scrotum as the
2:24
testes pass through them.
2:26
And here’s also a fun fact, the testicular vessels descend together with the testes,
2:32
and that is why the testicular arteries, or gonadal arteries, come from the lumbar region
2:37
of the abdomen as well.
2:39
So same goes for females and the ovaries.
2:43
Lymphatic drainage is similarly directed to the lumbar nodes.
2:48
Ok.
2:49
So we’re first going to cover the testes external structures,
2:53
Then we’ll open it up and cover its internal anatomy.
2:57
After that, we’re going to talk a little bit about the epididymis and finally go through
3:02
their coverings and external fixation.
3:04
Awesome.
3:06
Let’s do the external structures first.
3:08
Externally, the testicles have an upper pole and a lower pole.
3:12
It has an anterior border and a posterior border.
3:16
And if you look at the testes from an anterior perspective, you’ll also see that it has a
3:21
lateral surface and a medial surface.
3:24
So the external features of the testes are very simple.
3:28
Let’s now go ahead and look at the internal structures of it,
3:32
And we’ll start by removing all other structures we’re not interested in for now.
3:37
Now first off, we need to identify the most external layer.
3:41
And that is a capsule called Tunica Albuginea.
3:45
Tunica Albuginea is a dense membrane of connective tissue covering the testis.
3:51
And if we remove the lateral wall of the testis, you’ll see that Tunica albuginea covers the
3:58
external part of the testis.
4:00
Right underneath tunica albuginea, you’ll find the vascular layer, or tunica vasculosa,
4:07
containing primarily blood vessels.
4:09
Within the actual testis, you’ll find septae.
4:12
Or septa of the testis.
4:14
They are connective tissue that separates the inner structures of the testes into lobules,
4:20
called lobules of testes Now the lobules of the testis are regions
4:25
that contain single tubules.
4:27
Right?
4:28
So each lobule has a single tubule.
4:31
And each of these single tubules consists of convoluted seminiferous tubules, which
4:37
are coiled.
4:39
And once the tubule leaves the lobule, it’ll become straight, so straight tubules.
4:45
Now, what do these tubules look like underneath the microscope?
4:49
Here you can see lobules.
4:51
They literally look like pyramids, separated by septae of connective tissue that extend
4:56
inwards from the capsule, right?
4:59
Seminiferous tubules have a convoluted part that is within the lobule itself and a straight
5:05
part that concentrates towards where all the lobules meet.
5:09
These seminiferous tubules have Sertoli cells, which are larhe columnar cells as you see
5:16
here.
5:17
These cells have a very tight junction between them that they form the blood-testis barrier.
5:23
This barrier prevents the sperm from entering the bloodstream, which also prevents our body’s
5:29
immune system from mounting an immune response against the sperm cells.
5:33
So this barrier is very, very important.
5:36
You can also see the process of spermatogenesis in this slide, which, remember is the process
5:41
by which spermatogonia develop into sperm.
5:45
You can see some sperm cells located in the lumen of the tubule.
5:49
Leydig Cells are also called Interstitial Cells, and they’re called interstitial cells
5:54
because they’re found in the connective tissue, or interstitium, between seminiferous tubules.
6:01
Now the Leydig cells are round cells, as you see here, with vesicular nuclei and very eosinophilic
6:08
cytoplasm.
6:09
Remember earlier I told you that the male reproductive system has two really important
6:14
functional cells?
6:15
One of them is the Sertoli cells.
6:18
The other one is the Leydig cells.
6:20
Leydig cells secrete testosterone, the male sex hormone.
6:24
Alright.
6:25
So that is the lobules and the septae of the testicles.
6:29
More posteriorly, we have the mediastinum of the testis.
6:33
The mediastinum of the testis has a network of tubules called rete testis.
6:39
This network of tubules will give off efferent ductules, which continue into the epididymis.
6:46
And this happens in the head of the epididymis, the upper part of it.
Epididymis
6:50
So let’s go ahead a talk about the epididymis a little bit.
6:53
Now I want you to understand something about the epididymis.
6:58
It’s not really an organ of its own.
7:00
It doesn’t really have any functional cells.
7:02
The epididymis is actually just tubes that are coiled together so tightly that they form
7:08
a structure called the epididymis.
7:11
Now even though it doesn’t really have any functional cells on its own, the epididymis
7:16
does something really important for the testes.
7:19
And that is that it serves as a reservoir for the spermatozoa.
7:24
So the sperm cells mature within the epididymis.
7:28
And is provided with nutrition by the epididymis, so that they gain the capacity to move and
7:33
fertilise the ovum.
7:34
So, in reality, Spermatozoa spend 10–12 of their total 72 days of maturation within
7:42
the epididymis.
7:43
Awesome.
7:44
So externally, the epididymis has a head or caput, and as I mentioned earlier, the cranial
7:51
part of the head is formed by the efferent ductules that come from the mediastinum of
7:56
the testes; right?
7:58
Then we have the body of epididymis, which is formed by the convoluted ducts of the epididymis.
8:04
We got the tail of the epididymis, which connects to the ductus deferens.
8:08
Another thing we can mention here is that anatomically, there’s going to be a pouch
8:13
located at the lateral surface between the testis and the epididymis.
8:17
That pouch is called the sinus of the epididymis.
8:21
And here’s an anterior view just to make it easier to visualize it.
8:25
Alright, let’s go ahead and recap the ducts of the testes and the epididymis.
8:30
First, we got the convoluted seminiferous tubules within the lobules of the testes.
8:35
Then, we got the straight tubules that form the rete tests.
8:40
They continue into the epididymis as the efferent ductules.
8:45
Within the epididymis, we got the duct of epididymis, which continues as the ductus
8:50
deferens.
8:51
So that’s really how the tubules are arranged.
Coverings and Fixation of Testes and Epididymis
8:55
Let’s now go ahead and look at the coverings and the external fixation of the testes and
8:59
the epididymis.
9:00
Alright, let’s zoom in first.
9:03
The layer that is closest to the testes and the epididymis is the Tunica Vaginalis.
9:09
Tunica Vaginalis is originally a part of the peritoneum that became one of the layers of
9:15
the scrotum during the descent of the testis.
9:19
And notice that the tunica vaginalis is composed of two layers with a little space between
9:25
them.
9:26
We got the visceral layer covering the testis and the epididymis from the anterior and the
9:30
lateral aspects.
9:32
It fuses with the tunica albuginea, and then posteriorly the visceral layer continues into
9:39
the parietal layer.
9:41
Between the visceral and the parietal later, there’s a little space which contains a small
9:45
amount of serous fluid, just like the peritoneum does.
9:49
Notice how the tunica vaginalis covers the whole thing as a pouch, except the posterior
9:55
ends of the epididymis.
9:57
And that is because the visceral layer envelops all but the posterior aspect of the testis,
10:03
while the parietal layer lies against the scrotal wall.
10:07
Alright.
10:09
Remember I told you that the testes descend from the lumbar region in the retroperitoneal
10:14
space?
10:15
And as they descend, they take with them all layers of the abdominal wall to form the scrotum?
10:21
The inner layer comes from the peritoneum, called tunica vaginalis.
10:27
Externally to that, there’s the internal spermatic fascia, which is a continuation of the transveralis
10:33
fascia of the abdominal wall.
10:36
Then externally to the internal spermatic fascia, we have a muscle called the cremaster
10:42
muscle, which is a skeletal muscle that pulls the scrotum towards the abdominal wall.
10:48
So when it gets cold, these muscle fibers contract to pull the testes closer to the
10:53
body, and if it gets hot, they relax.
10:58
These muscle fibers, the cremaster muscle, consists of muscle bundles from the internal
11:03
oblique and transversus abdominis muscles, and it’s covered by the cremasteric fascia.
11:10
Externally to this muscle, we have the external spermatic fascia, which is a continuation
11:15
of the superficial abdominal fascia Now just to complete the picture here.
11:20
Externally to this layer, we’re going to have the dartos fascia, which is a layer of connective
11:25
tissue found in the scrotum and foreskin in males, and the vaginal lips in females.
11:31
And then externally to that, we have the skin.
11:34
These are basically all the layers of the scrotum.
11:37
But now, these layers.
11:39
The external spermatic fascia, the cremaster muscle, and the internal spermatic fascia.
Spermatic Cord
11:45
They’re going to continue upwards and form the spermatic cord.
11:49
Or Funiculus Spermaticus.
11:51
So here you see a naked testicle covered by tunica vaginalis.
11:56
Externally to that, we can see the internal spermatic fascia.
12:01
Externally to that, we see the cremaster muscle.
12:03
External to that, again, we see the external spermatic fascia.
12:08
And again, here we see the spermatic cord.
12:11
So let’s expose the spermatic cord a little.
12:14
Let’s cut the external spermatic fascia here.
12:17
Let’s cut the cremaster muscle here.
12:20
Let’s cut the internal spermatic fascia here.
12:23
And let’s cut through the anterior part of the tunica vaginalis, and then look at the
12:28
whole thing from this perspective.
12:31
We’ll see this.
12:32
I know I’m repeating myself many times here but I really want you to remember this.
12:36
So here we see the external spermatic fascia.
12:39
Cremaster muscle, Internal Spermatic fascia, and down here, we can see the tunica vaginalis.
12:46
We can also see the testes and the epididymis.
12:49
Alright.
12:50
So up here, we can see the inguinal canal.
12:52
And down here, we can see the scrotum.
12:56
Right?
12:57
Between the inguinal canal and the scrotum, we can see the spermatic cord.
13:01
So the spermatic cord is a tough rope-like structure that goes from the scrotum to the
13:07
inguinal canal.
13:08
Within the spermatic cord.
13:10
We can find the ductus deferens coming from the epididymis.
13:14
But we can also find vessels.
13:16
We can find the artery to the ductus deferens, which is a branch of the internal iliac artery
13:20
that supplies the ductus deferens.
13:23
We can find the Testicular artery, which is a branch of the abdominal aorta supplying
13:27
the testis and the epididymis.
13:30
We have lymph vessels from the testis and the epididymis that flow to the lumbar lymph
13:36
nodes.
13:37
We have the Pampiniform plexus, which is a venous plexus conveying blood from the testis
13:42
and epididymis to the inferior vena cava on the right and to the left renal vein on the
13:48
left We got the Testicular plexus which is basically
13:52
the nervous plexus of the testis, and the Deferential plexus, which are visceral sensory
13:59
nervous plexus of the ductus deferens.
14:02
So that was everything I had regarding the spermatic cord and the testes and epididymis
Ductus Deferens
14:08
as well.
14:09
Let’s now go ahead and talk a little bit about the ductus deferens
14:12
The ductus deferens is a tubular organ that transports spermatozoa from the epididymis
14:19
to the prostatic urethra by peristaltic contractions.
14:23
Right?
14:24
So It passes from the scrotum through the spermatic cord and inguinal canal into the
14:29
lesser pelvis, where it crosses the ureter and enters the Prostate.
14:34
Alright.
14:35
Now the ductus deferens have different parts according to their location.
14:40
If it’s in the scrotum, it’s called the scrotal part.
14:43
After the scrotal part, it goes within the spermatic cord.
14:47
Called the funicular part.
14:49
Then it enters the inguinal canal through the superficial inguinal ring, getting the
14:54
name inguinal part.
14:56
Then it leaves the inguinal canal through the deep inguinal ring and enters the pelvis,
15:02
called the pelvic part.
15:04
The pelvic part of the ductus deferens is going to go through the lesser pelvis, and
15:09
pass anterior to the external iliac vessels.
15:13
It’ll run close to the urinary bladder And dilate to form the ampulla of the ductus
15:19
deferens, which is the most distal segment of the ductus deferens.
15:23
Then ductus deferens will fuse with the duct of the seminal gland to form the ejaculatory
15:29
duct, which will enter the Prostate and join the urethra—the prostatic urethra at the
15:35
seminal colliculus.
15:37
Alright.
15:38
That was all for the ductus deferens.
Seminal Gland
15:41
Let’s go through the next segment of the male genital system, which is this one.
15:45
The Seminal gland.
15:46
The seminal gland is very, very important as well.
15:50
The seminal glands are located behind the urinary bladder above the Prostate.
15:56
Each seminal gland is a simple tubular gland composed of a single duct with multiple convolutions.
16:04
The seminal glands produce 50–80 % of the ejaculate fluid.
16:08
So it produces a fluid that makes up semen, which is released during ejaculation.
16:14
So the seminal gland has an excretory duct, which joint joins the ductus deferens, as
16:20
you see here, to form the ejaculatory duct that empties into the urethra.
16:25
Awesome.
Prostate
16:27
Let’s continue to the next segment and talk about the Prostate.
16:30
Now the Prostate is the largest male genital gland.
16:34
And it produces roughly about 30% of the ejaculate fluid.
16:39
It is located sub peritoneally, so under the peritoneum.
16:44
And also inferior to the urinary bladder.
16:47
The urethra goes through the Prostate along with the paired ejaculatory ducts.
16:53
Alright.
16:54
Externally, there’s a base called the base of the Prostate, which is the broad cranial
17:00
part of the Prostate located around the neck of the urinary bladder.
17:04
We have an apex of the Prostate, which is the tip of the Prostate pointing towards the
17:09
pelvic floor There’s a posterior surface facing the rectum
17:13
and an anterior surface facing the pubic symphysis.
17:17
And then, within the Prostate, we got the urethra.
17:20
Or, to be specific, the prostate part of the urethra.
17:24
Alright, let’s zoom in a little bit.
17:26
Now the Prostate is divided into zones.
17:30
Histological zones, not anatomical.
17:32
But I wanna mention them anyway because the Prostate is built differently across the inner
17:38
surface of it.
17:40
So the outer part of the Prostate, we got the peripheral zone.
17:44
This zone is rich in glands that produce seminal fluid.
17:49
Around the ejaculatory ducts and the prostatic utricle, there’s the central zone.
17:55
There’s also a transitional zone around the proximal part of the urethra.
17:59
The transitional zone is where benign prostatic hyperplasia occurs and can lead to bladder
18:05
outlet obstruction when an adenoma grows to a significant size.
18:10
Then the rest is usually a non-glandular zone composed of fibromuscular stroma
18:15
Again, these are microscopic zones, so histological zones not anatomical.
18:21
Just keep in mind that the Prostate has zones.
18:24
Some parts have more glands; some parts have more ducts.
18:29
Some parts have more muscles and fibers.
18:31
Now, if we make a vertical cut like this, then look at the Prostate from this perspective.
18:37
We’ll see this.
18:38
So on the posterior surface of the Prostate.
18:42
We can see prostatic ductules, which secrete the prostatic secretions.
18:46
We ca see the urethral crest, which is an elevated crest on the posterior surface of
18:51
the urethra There’s an elevated area on the urethral crest
18:56
called Seminal colliculus And on the seminal colliculus, you can find
19:00
the prostatic utricle, which is an unpaired remnant of the paramesonephric duct.
19:06
And we can find the openings of the ejaculatory ducts on both sides of the seminal colliculus
19:12
for the sperma.
19:14
So that was all I had for the Prostate.
Bulbourethral Glands
19:17
Let’s now do the bulbourethral glands.
19:19
The bulbourethral glands are a pair of accessory genital glands.
19:25
They lie closely above the bulb of the Penis, and empty their fluid into the beginning part
19:31
of the spongious urethra.
19:33
These pea-sized glands are located on the inferior surface of the deep, transverse perineal
19:39
muscle.
19:40
They produce a viscous liquid that lubricates the internal surface of the urethra during
19:46
ejaculation.
Male Urethra
19:47
Awesome.
19:48
Let’s quickly go through the male urethra.
19:50
So here we see the urinary bladder.
19:53
The Prostate.
19:54
The Perineal muscles and the Penis.
19:56
The male urethra is here, going through all of these structures.
20:00
So it goes from the internal urethral orifice to the urinary bladder.
20:05
To the external urethral orifice, exiting the glans penis.
20:09
Now.
20:10
The urethra is divided into several parts based on the region they’re located in.
20:16
In the Prostate It’s called the prostatic urethra.
20:19
In the perineum, it’s called the membranous urethra.
20:23
And in the Penis, it goes through the corpus spongiosum so it’s called the spongious urethra.
20:29
Alright!
20:30
That was all the internal make genital organs that we needed to cover.
20:34
We went through the testes and the epididymis.
20:37
We went through the ductus deferens.
20:38
The seminal gland and the ejaculatory duct We went through the Prostate, the male urethra,
Penis
20:45
and the bulbourethral glands Let’s now go through the external genital
20:49
organs, which consist of the Penis and the Scrotum.
20:52
We’ll start with the Penis.
20:54
And similar to most things, it has external structures and internal structures.
20:59
So let’s start by talking about the external structures we’ll see looking at the Penis.
21:03
So here’s a lateral view of the Penis.
21:06
But to really be able to cover all external structures, we need to look at it from an
21:11
inferior surface as well, so let’s go ahead and do that.
21:14
So essentially, the Penis consists of 3 pipes, or three erectile bodies, that courses throughout
21:21
its entire length.
21:23
We have 2 Corpora cavernosa penis, which are erectile bodies that erect the Penis when
21:30
engorged with blood, and 1 Corpus spongiosum penis, which is the unpaired erectile body
21:36
containing the urethra.
21:38
So within the corpus spongiosum, that’s where we have the spongy part of the male urethra.
21:45
The Penis can be divided as the root of the Penis, which is the inner part covered by
21:50
skin and muscles.
21:51
We have the body of the Penis, which is the external movable part of the Penis beneath
21:56
the pubic symphysis.
21:58
And we have the glans penis, which is the anterior end.
22:02
Now the root of the Penis, consists mainly of the bulb of Penis, which is the dilated
22:08
part of the corpus spongiosum underneath the perineum.
22:12
And two crura of Penis, which are the paired internal part of the corpora cavernosa.
22:18
Now, the body of Penis is also composed of corpora cavernosa and the corpus spongiosum.
22:25
But anatomically, the body of the Penis has surfaces as well.
22:29
It has the Dorsum of Penis, which is the “anterior” surface in a flaccid penis in the anatomical
22:35
position, And when erect, you know, it becomes the upper to posterior surface.
22:40
It has a Urethral surface, which is the surface facing the scrotum
22:45
Then we can see Fundiform ligament of Penis, which originates at the linea alba of the
22:51
anterior abdominal wall, and makes a loop around the Penis, attaching the Penis to the
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pubic symphysis.
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And we can see the Suspensory ligament of Penis, which attaches the dorsum of the Penis
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to the anterior surface of the pubic symphysis.
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Now, there’s one more structure that I wanna mention in the body of Penis.
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And that is, if we look at the Penis from an inferior perspective.
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On the inferior side, there’s going to be a line, or a raphe called the raphe of Penis.
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So that was the body of Penis.
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Now let’s do the glans penis.
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The glans penis is the most distal segment of the corpus spongiosum.
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It’s also referred to as the head of the Penis.
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Similar to glans clitoris, the glans penis is the most sensitive erogenous zone and primary
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anatomical source of male sexual pleasure, due to the number of nerve endings.
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Alright, let’s zoom in and look at the structures.
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The proximal dilated part of the glans that faces the body of the Penis, is called the
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corona of glans.
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It also has a neck, which is a groove that separates the glans from the body of the Penis.
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Around the glans penis, we can find the foreskin or the prepuce.
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The foreskin is a fold of skin that originate from the body of the Penis and cover the glans.
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It can be pulled over the glans to a variable extent.
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Then we can find a frenulum, which is ventrally located.
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It’s the transition between the skin of glans and the skin of the prepuce.
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And lastly, we can also find some preputial glands, which are small smegma-producing glands
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at the inner margin of the foreskin.
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Smegma is a thick, white, cheesy substance composed of dead skin cells and oil and other
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fluids, that collects under the foreskin of the Penis.
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It’s more common in uncircumcised men who don’t clean that area well enough.
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Women can also get smegma in their vaginal area
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So that was the external surfaces of the Penis.
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Let’s now make a transverse cut, like this.
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Remove some parts of the Penis.
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And look at it from this perspective We’ll see this.
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This image illustrated the penis structures very well,
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We can see the Corpus spongiosum down here, containing the urethra.
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We can see corpora cavernosa Around the corpora cavernosa, we can see tunica
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albuginea, which is a dense layer of connective tissue that from a septum, called septum penis
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between the corpora cavernosa.
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We can also see the deep fascia of the Penis, which is a layer of connective tissue covering
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the erectile bodies.
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And we have the superficial fascia of Penis, which enables free sliding of the skin.
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So it’s located right underneath the skin.
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Alright.
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Other structures we can see, which are very very important, is the superficial dorsal
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vein of the Penis.
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This is an unpaired vein that drains through the external pudendal veins into the common
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femoral vein.
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We also have the deep dorsal vein of the Penis, which is an unpaired vein that bifurcates
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into the internal pudendal vein, which converges into the internal iliac vein
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On the sides of it, we can see the dorsal artery of the Penis, which supplies the skin
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and glans of the Penis and the foreskin.
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Then within the corpora cavernosa, we can see cavernous spaces and trabeculae of corpora
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cavernosa.
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These are spaces that fill with venous blood during an erection.
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So they’re small cavities inside the erectile bodies lined with endothelium
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And in the middle, we can find the Deep artery of Penis, which is inside the corpus cavernosum.
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And in corpus spongiosum, we can see the urethral artery.
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So that was everything I had for the Penis.
Scrotum
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Now lastly, let’s talk a little bit about the scrotum.
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The scrotum is a sac located on the outside of the body.
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Right?
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So if we go ahead and look at the scrotum from this perspective, we’ll see this.
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So again, as we talked about earlier, the scrotum contains the testis and epididymis.
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And also the ductus deference on the posterior aspect.
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The temperature inside the scrotum is 2–4 degrees lower than the core body temperature.
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This ensures optimal spermatogenesis because the optimal temperature for spermatogenesis
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is a little colder than our core temperature.
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If if it gets too cold outside, the cremaster muscle contracts and pulls the scrotum upwards,
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towards the perineum.
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Similarl if it gets too hot, the cremaster muscle relaxes.
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Alright.
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So the layers are as follows.
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First, we have the tunica vaginalis.
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Which remember comes from the peritoneum.
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Externally to that, there’s the internal spermatic fascia, which is a continuation of the transveralis
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fascia of the abdominal wall.
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Then externally to the internal spermatic fascia, we have a muscle called the cremaster
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muscle, which consists of muscle bundles from the internal oblique and transversus abdominis
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muscles.
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Externally to this muscle, we have the external spermatic fascia, which is a continuation
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of the superficial abdominal fascia Externally to this layer, we’re going to have
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the dartos fascia.
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This is a 1 – 2 mm thick layer of connective tissue with elastic fibers and smooth muscles.
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And it’s going to form a septum, or scrotal septum, which divides the scrotal pouch into
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two cavities for each testicle.
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Outside the dartos fascia is the skin, as you see here.
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All of these layers form the scrotum.
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So that was everything I had for the anatomy of the male genital system.
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I really hope you found this video helpful.
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If you did, don’t forget to like, comment, and subscribe!
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See you next time.