Reproduction 2- Male anatomy

Summary

This educational script delves into the basics of male reproductive anatomy, highlighting the similarities and differences between the sexes. It explains the role of sperm as male gametes, the function of the testes in gamete production, and the unique erectile tissue of the penis that enables erection. The script also touches on the nervous system's control over erection and ejaculation, providing a foundational understanding of male reproductive physiology.

Takeaways

• 🧬 Both men and women have copulatory organs, gonads, and gametes, which are essential for reproduction.
• 🔬 Male gametes are sperm, single-celled, haploid cells with half the DNA of the body's other cells.
• 💡 The male gonads, the testes, are responsible for producing sperm and are located in the scrotum.
• 🌟 The penis is the male copulatory organ, composed of erectile tissue that enables an erection for sexual intercourse.
• 📐 The penis has three columns of erectile tissue: the corpus spongiosum and two corpora cavernosa.
• 🩸 The corpus spongiosum surrounds the urethra and fills with blood during arousal, contributing to an erection.
• 🔄 The erection process is controlled by the parasympathetic nervous system, which facilitates blood flow into the erectile tissue.
• 💧 Ejaculation is controlled by the sympathetic nervous system, which takes over after an erection to release the built-up blood.
• 🛡️ The prepuce, commonly known as the foreskin, is a structure that covers the penis and may be removed during circumcision.
• 👶 The scrotum is a skin bag that houses the testes, protecting them and maintaining an optimal temperature for sperm production.
• 🚺 The script also mentions that the corresponding female reproductive parts will be discussed in a subsequent lecture.

Q & A

What are the three main components of the human reproductive system mentioned in the script?

The three main components of the human reproductive system mentioned are the copulatory organ, the gonads, and the gametes.

What is the purpose of gametes in the reproductive system?

The purpose of gametes is to combine with another haploid cell to form a new individual, as they contain half the amount of DNA, making them essential for reproduction.

What are the male gametes called and what makes them unique?

The male gametes are called sperm. They are unique because they are single-celled, haploid cells containing half the amount of DNA.

What is the male gonad responsible for producing gametes called?

The male gonad responsible for producing gametes is called the testes, which is plural for testis.

How many testes does a male typically have?

A male typically has two testes, which are the organs responsible for sperm production.

What is the male copulatory organ and what is its main function?

The male copulatory organ is the penis, and its main function is to deliver sperm to the female during sexual intercourse.

What is the anatomical structure that allows the penis to change from a flaccid to an erect state?

The penis contains erectile tissue, specifically three columns of spongy tissue, which fill with blood during arousal, allowing the penis to become erect.

What is the role of the parasympathetic nervous system in penile anatomy?

The parasympathetic nervous system controls erection by facilitating the filling of the spongy erectile tissue with blood.

How does the sympathetic nervous system relate to penile anatomy?

The sympathetic nervous system controls ejaculation and the return of the penis to its flaccid state after arousal.

What is the anatomical term for the structure commonly known as the foreskin?

The anatomical term for the structure commonly known as the foreskin is the prepuce.

Where do the testes reside in the male anatomy?

The testes reside within a skin bag called the scrotum.

Outlines

00:00

😎 Male Reproductive Anatomy: Gametes and Gonads

The script begins with an introduction to male gross anatomy, emphasizing the similarities and differences between male and female reproductive systems. It highlights that both sexes have copulatory organs, gonads, and gametes. The male gametes, or sperm, are haploid cells with half the DNA, serving the primary purpose of the reproductive system. The male gonads, known as testes, are responsible for sperm production. The lecture promises to delve into the process of sperm creation in a later section.

05:06

🌟 Anatomy of the Penis: Erectility and Erection Mechanism

This paragraph delves into the anatomy of the male copulatory organ, the penis, focusing on its erectile tissue and the process of achieving an erection. The penis contains three columns of erectile tissue: the corpus spongiosum, which surrounds the urethra, and two corpora cavernosa on either side. During arousal, these tissues fill with blood, leading to an erection. The parasympathetic nervous system controls this process, while the sympathetic nervous system is responsible for ejaculation. The summary also touches on the prepuce or foreskin, a structure removed during circumcision.

10:06

👕 External Male Anatomy: Prepuce and Scrotum

The final paragraph of the script discusses additional external male anatomy, including the prepuce (foreskin) and the scrotum. The prepuce is a removable structure that covers the penis, particularly in the context of circumcision. The scrotum is described as a skin bag housing the testes, where the male gametes and the process of sperm production take place. The summary provides a brief overview of the external structures and their functions in the male reproductive system.

Keywords

💡Copulatory Organ

A copulatory organ is a specialized anatomical structure in animals used for sexual reproduction. In the context of the video, it refers to the male organ responsible for delivering sperm to the female. The script mentions that both men and women have a copulatory organ, but the focus is on the male's, which is the penis, highlighting its role in the reproductive process.

💡Gametes

Gametes are the reproductive cells in sexually reproducing organisms that fuse during fertilization. The script defines them as cells with half the amount of DNA, making them haploid. In males, the gametes are sperm, which are essential for reproduction as they carry genetic information to combine with the female's haploid cell, the egg.

💡Sperm

Sperm are the male reproductive cells, or gametes, which are haploid and carry genetic information necessary for reproduction. The script describes sperm as single-celled organisms with half the DNA of a typical body cell, designed to fertilize the female's egg. The production and delivery of sperm are central to the discussion of male reproductive anatomy.

💡Gonads

Gonads are the organs that produce gametes in animals. In the script, the male gonads are referred to as testes, which are responsible for sperm production. The term is crucial for understanding the function of the testes in the male reproductive system.

💡Testes

Testes are the male gonads that produce sperm. The script explains that there are two testes in males, each responsible for sperm production. The term is used to discuss the anatomy and function of these organs in the context of the male reproductive system.

💡Penis

The penis is the male copulatory organ discussed in the script. It is described as having erectile tissue that allows it to change from a flaccid to an erect state, which is essential for sexual intercourse. The script delves into the anatomy of the penis, including the erectile tissue and the process of achieving an erection.

💡Erectile Tissue

Erectile tissue is a type of tissue in the penis that can fill with blood, causing an erection. The script explains that the penis contains three columns of erectile tissue, which are crucial for the organ's function during sexual arousal. The term is central to understanding the physiological process of erection.

💡Corpus Spongiosum

The corpus spongiosum is a column of erectile tissue within the penis that surrounds the urethra. The script describes it as the 'spongy body' and explains its role in the erectile process, where blood fills this tissue during arousal, leading to an erection.

💡Corpora Cavernosa

The corpora cavernosa are two columns of erectile tissue on either side of the corpus spongiosum in the penis. The script mentions that these tissues fill with blood during arousal, contributing to the erection. The term is important for understanding the anatomy of the penis and the mechanism of erection.

💡Parasympathetic Nervous System

The parasympathetic nervous system is part of the autonomic nervous system that controls erection. The script notes that this system is responsible for the process of filling the erectile tissue with blood, resulting in an erection. It is a key concept in understanding the physiological control of erections.

💡Ejaculation

Ejaculation is the process of expelling semen from the male reproductive system, which includes sperm and other fluids. The script mentions that the sympathetic nervous system controls ejaculation, which is the culmination of sexual arousal and leads to the end of the erection. The term is integral to the discussion of male sexual function.

💡Prepuce

The prepuce, commonly known as the foreskin, is a fold of skin that covers the glans of the penis. The script discusses the prepuce in the context of circumcision, a procedure where it is removed. Understanding the prepuce is important for discussing cultural practices and male anatomy.

💡Scrotum

The scrotum is the skin pouch that houses the testes in males. The script describes it as a 'skin bag' where the testes live, protecting them and maintaining an optimal temperature for sperm production. The term is essential for understanding the external male reproductive anatomy.

Highlights

Introduction to male gross anatomy focusing on the reproductive system.

Both men and women have copulatory organs, gonads, and gametes.

Sperm are the male gametes, which are single-celled and haploid.

The testes are the male gonads responsible for sperm production.

The penis is the male copulatory organ with unique erectile tissue anatomy.

Erection involves a shift from flaccidity to rigidity due to blood flow into erectile tissue.

The corpus spongiosum is a column of erectile tissue that surrounds the urethra.

Blood flow during arousal fills the erectile tissue, leading to an erection.

Erection is controlled by the parasympathetic nervous system.

Ejaculation is controlled by the sympathetic nervous system, ending the erection.

The prepuce, or foreskin, is a structure that may be removed during circumcision.

The scrotum is the skin bag housing the testes.

The urethra is the channel through which both gametes and urine exit the body.

The corpora cavernosa are two columns of erectile tissue that fill with blood for an erection.

Anatomy terms distinguish between the singular and plural forms, such as corpus and corpora.

The anatomy of the male reproductive system is intricately designed for reproduction.

Transcripts

- The fellas won, we're starting out with male gross anatomy.

So the first thing that we want to look at is the fact

that men and women,

human critters, both have a copulatory organ,

they both have gonads, and they both have gametes.

And when I give you--

I mean, this probably isn't difficult.

So when we figure out the male parts,

it should be pretty quick for you to figure out

the corresponding female parts,

but we'll save them for the next lecture.

So the copulatory organ for the fellas,

this is the structure that is responsible for-- well,

maybe we should start backwards.

Perhaps we should start with the gametes,

which are the cells that are the whole purpose

of the reproductive system in the first place.

So in the fellas, the gametes are sperm.

And I know you remember from your rocking early biology days,

that sperm are single celled cells.

I was about to call them critters.

They kind of remind you of critters if you think about it.

They're single cells that have half the amount of DNA.

So they're haploid cells, and this is all review.

By the nature of being haploid,

they only have one copy of each chromosome.

That's what it means to be haploid.

If you think about it,

of course it makes complete sense that if you're going to

have a haploid cell that has only one copy,

we know that all the rest of our cells

have two copies of every chromosome.

So therefore, we must combine two haploid cells.

The ladies have the other haploid cell

that is necessary to make a baby.

Now the gonads are organs

that are responsible for producing gametes.

So the fellas, the gonads

that make gametes are the testes.

And testes, that's plural.

And if it's singular,

you are talking about only one testis.

Don't mix it up.

But the fellas have two testes, they have two gonads,

and the testes are the site of sperm production.

We're going to spend an entire section

talking about how sperm are made.

And then in order to deliver the sperm-- I mean,

one critter has the sperm and the other critter has the egg.

And so there has to be some sort of anatomy

that enables the sperm and the egg to come together.

Different animals

have different strategies for carrying this out.

Not everyone has such

a copulatory organ as human critters.

There are many very interesting copulatory organs out there.

So, the fellas, their copulatory organ is the penis.

And the penis

has some pretty incredible anatomy that we get to look at.

Let's start by looking at penis anatomy.

First of all, penises are--

I will try not to make a commentary on penises.

Penises are floppy structures

that would be completely ineffective as copulatory organs

if they could not change from floppiness to erectness.

And so the anatomy

of the penis is set up to enable a shift from floppy to erect.

That means that the penis is actually composed of,

I don't know,

pieces of tissue, structures that contain erectile tissue.

And there's actually, like, three bands.

And that's a terrible word because bands kind of imply,

like, going around this way.

There are actually, like, three columns.

Columns. I don't like band.

There are three columns of erectile tissue in a male penis.

And you can see-- I'm going to--

obviously I'm starting with penile anatomy first.

So, I'm going to have to draw all over this.

You can see my external penis here.

It's not my penis. And you can see kind of a--

I don't know,

like, doesn't it look kind of dotty all around here?

This is one of my columns of erectile tissue,

and it is called the corpus spongiosum.

Corpus is singular. It means body.

So this is basically the spongy body.

And if I were to draw a line around my corpus spongiosum,

you'll see that it actually travels all

the way in to the penis. Like, it's the whole--

almost the bulk of the penis is corpus spongiosum.

And when I say it's erectile tissue, the structure--

it's like it really is spongy.

And there's this whole anatomical phenomenal setup

whereby blood--

during arousal blood can enter the penis

and it can enter this spongy zone.

And the vessels that are feeding the blood in

are linked to vessels that are draining the blood.

However, during arousal,

when the blood keeps getting fed in,

blood is fed in faster and the penis fills up with blood.

It, like, grows in size, which makes sense

because there is more blood coming in here

because of arousal.

That the act of filling it with more blood actually

blocks off the exit route, so now the blood is stuck.

And there's a whole bunch of blood in there,

but it can't get out.

And it's not going to be able to get out.

That whole thing-- that process of forming an erection

by filling all this spongy tissue with blood,

that's under control

of the parasympathetic nervous system.

So let's make a note of that over here.

Parasympathetic innervation controls erection.

Erection happens because the spongy tissue fills with blood,

and then the actual erection

itself blocks off the blood supply to leave.

So the blood gets stuck there

and your erection lasts until somebody else

comes into the mix.

If parasympathetic nervous system controls an erection,

sympathetic nervous system controls ejaculation.

So the erection will maintain

until the sympathetic nervous system takes over

and ejaculation takes place. And we'll talk about all--

like how does ejaculation happen, what is in there.

Like, we'll talk about all those details.

But once the sympathetic nervous system takes over,

then we no longer have the stimulus

that was creating the parasympathetic scene,

and the blood vessels change

and the blood route to get out is--

comes back,

and so the blood can leave your penis and now you--

your penis is back to being not erected or erectile.

No longer erect.

Thank you. I got there.

Corpus spongiosum, there's only one of these things.

It fully surrounds--

like, it forms a complete-- oh, no.

The spongy urethra travels through corpus spongiosum.

That's going to help you too.

So spongy, that says spongy, urethra travels through it.

So if we actually did like a cross section.

Like if I went and whacked off this penis-- I'm really sorry,

that was a rather violent image. But if you sliced it--

if you did a dissection line and then you looked at the penis,

you would actually see the urethra right

down the middle of corpus spongiosum.

But I told you that there were three columns, and there are.

This is part of my--

one of my other two columns.

And in this diagram we can't actually see both of those.

And this is called the corpus-- and I'm going to do--

my other two are called corpora,

plural, cavernosum.

Caverno-- caverno-- cavernosa.

Corpora cavernosa, and that's plural.

We also-- if we wanted to say we just have one of them,

it's corpus cavernosum.

So when you see it corpus cavernosum,

it's the same thing as corpora cavernosa.

It's just singular. And corpora cavernosa is plural.

So it reminds us that there are two of these things.

If I were to draw that section

that I was telling you about of the penis,

where here is my urethra, and this is my spongy-- I mean,

corpus spongiosum,

then corpora cavernosa would kind of look like this.

There's two bands that travel down the penis.

They function exactly the same. They fill with blood.

They're spongy, erectile tissue.

More external anatomy.

So when you're born with your penis,

you actually have a structure called the prepuce

that is this little, like, sock thing.

I don't know, it looks something like that.

And it's called the foreskin.

I already said it was called the prepuce.

We know of it as the foreskin. And this structure--

you can call it prepuce or fore--

you should probably call it prepuce because that's,

like, the anatomy term.

But you should also know that it's the foreskin.

Yeah. And this is a structure

that during circumcision is actually removed

from male baby boys.

Not everybody has their prepuces removed.

And there was something else. All right.

I wanted to tell you the structure

that your gonads live in-- okay, so these are the testes.

That's one testis, and the other testis is on the other side.

And the testes live

inside a little skin bag called the scrotum.

And I think this is the bulk of the anatomy.

We know that this is the spongy urethra.

We know that this is the external urethra orifice.

And we know that gametes and urine come out of that opening.

All right, let's talk about the ladies.