Reproductive embryology
Summary
TLDRIn this educational video, ABD, a medical student at Kingd Aiz University, delves into the intricate process of embryology, focusing on the development of the reproductive system. The discussion begins with the migration of primordial germ cells to the gonadal ridge, where they differentiate into future gametes. ABD explains the roles of various cells in gonadal development, the significance of the genital ducts, and how hormones like testosterone and dihydrotestosterone influence the formation of male and female genitalia. Clinical implications, such as disorders in testosterone function leading to ambiguous genitalia, are also explored. The video is a comprehensive guide for students and medical professionals interested in understanding the complex journey of reproductive system development.
Takeaways
- 🌟 The video discusses embryology, focusing on the development of the reproductive system.
- 🔍 Primordial germ cells migrate to the gonadal ridge, which will later develop into gametes or support structures.
- 🌐 In the gonadal ridge, three types of cells are present: primordial germ cells, mesothelial cells, and mesenchymal cells, each contributing to different structures.
- 🧬 Male development is characterized by the presence of the Y chromosome and the SRY gene, which triggers the production of testosterone and other hormones.
- 🚹 In males, the wolfian duct develops into the epididymis, vas deferens, and seminal vesicles, while the Müllerian duct regresses due to the action of Müllerian Inhibiting Factor (MIF).
- 🚺 In females, without hormonal input, the Müllerian duct develops into the uterus, Fallopian tubes, cervix, and upper vagina, and the wolfian duct regresses.
- 🌡 Hormones play a critical role in sexual differentiation; without them, the default development is female.
- 🧪 The video mentions clinical implications, such as individuals with XY chromosomes who do not produce functional testosterone, leading to female external genitalia but internal male structures.
- 🔎 The urogenital sinus develops into different structures in males and females, including parts of the urinary system and the lower vagina in females.
- 📚 The presenter recommends 'First Aid for the Basic Sciences: General Principles' and 'Kaplan Step 1 Physiology' as resources for further study.
Q & A
What is the role of primordial germ cells in the development of the reproductive system?
-Primordial germ cells migrate to the gonadal ridge and give rise to future gametes, such as spermatogonia in males and oogonia in females.
What are the three types of cells found in the gonadal ridge during embryonic development?
-The three types of cells in the gonadal ridge are primordial germ cells, mesothelial cells, and mesenchymal cells, which contribute to the formation of gametes, supporting structures, and other reproductive tissues.
How do the genital ducts, specifically the Müllerian and Wolffian ducts, contribute to the formation of internal genital structures?
-In males, the Wolffian duct develops into the epididymis, vas deferens, and seminal vesicles, while in females, the Müllerian duct develops into the uterus, fallopian tubes, cervix, and upper one-third of the vagina.
What is the significance of the SRY gene in determining sex during embryonic development?
-The SRY gene, located on the Y chromosome, is crucial for male sex determination. It encodes for a protein that initiates the development of testes, which then produce hormones necessary for male reproductive system development.
What is the role of Müllerian inhibiting factor (MIF) in the development of the male reproductive system?
-Müllerian inhibiting factor (MIF), produced by Sertoli cells in the testes, inhibits the development of the Müllerian duct, leading to its regression and preventing the formation of female internal reproductive structures in males.
How does the absence of hormonal input affect the development of the genital ducts?
-Without hormonal input, such as testosterone and anti-Müllerian hormone, the Wolffian duct regresses in females, while the Müllerian duct regresses in males, leading to the development of female or male reproductive structures, respectively.
What structures develop from the genital tubercle in both males and females?
-The genital tubercle develops into the glans penis in males and the glans clitoris in females.
What is the clinical significance of androgen insensitivity syndrome as discussed in the script?
-Androgen insensitivity syndrome results from a failure of testosterone to act properly, leading to the development of external female genitalia despite the presence of XY chromosomes and testes. Affected individuals may present with primary amenorrhea and internal male reproductive structures.
How does the urogenital sinus contribute to the formation of the urinary system in both sexes?
-The urogenital sinus gives rise to the urinary bladder and urethra in both males and females. In males, it also forms the prostate gland and bulbourethral glands, while in females, it contributes to the lower third of the vagina and greater vestibular glands.
What is the role of the gubernaculum in the migration of the testes?
-The gubernaculum assists in the migration of the testes from the abdomen to the scrotum, guiding their descent and positioning.
Outlines
🌱 Embryology of the Reproductive System
The video begins with an introduction to embryology, focusing on the development of the reproductive system by a medical student from Kingd Aiz University. The discussion starts with the migration of primordial germ cells to the gonadal ridge, which will eventually form the gametes. The gonadal ridge contains three types of cells: primordial germ cells, mesothelial cells, and mesenchymal cells, each contributing to different structures in males and females. The video also covers the development of genital ducts, explaining the roles of the Müllerian and Wolffian ducts in forming internal genital structures. The influence of hormones, such as testosterone and Müllerian inhibiting factor (MIF), is highlighted in determining the sex of the developing reproductive system.
🔬 Hormonal Influences on Genital Development
This section delves into the clinical aspects of genital development, emphasizing the role of hormones in shaping the genital tract. The video explains how the absence of hormonal input leads to the development of female genitalia, while the presence of hormones like testosterone and dihydrotestosterone (DHT) leads to male genital development. Conditions where testosterone is non-functional are discussed, resulting in the regression of male-specific ducts and the development of female external genitalia despite the presence of XY chromosomes. The video also provides a visual aid to understand the undifferentiated genital tract and how it can develop into either male or female structures based on hormonal cues.
🧬 Clinical Implications and Further Development
The video continues with a clinical perspective, discussing how certain conditions can lead to atypical development of the reproductive system. It explains the impact of hormonal imbalances on the development of the urogenital sinus, gonads, and external genitalia. The role of the gubernaculum in testes migration and the formation of ligaments in both sexes are also covered. The video provides a detailed look at the differentiation of the urogenital sinus and the development of the urinary system, highlighting the common structures in both males and females. It concludes with a brief mention of the development of external genitalia, setting the stage for further discussion.
📚 Resources and Conclusion
In the final part of the video, the presenter shares resources used for the presentation, recommending 'First Aid for the Basic Sciences' and 'Kaplan Step 1 Physiology' for further reading on embryology and the development of the genital tract. The presenter invites questions and comments, providing contact information for further engagement. The video concludes with a summary of the key points covered and a thank you note to the viewers.
Mindmap
Keywords
💡Primordial Germ Cells
💡Gonadal Ridge
💡Mesothelial Cells
💡Müllerian Duct (Paramesonephric Duct)
💡Wolffian Duct (Mesonephric Duct)
💡Testosterone
💡Anti-Müllerian Hormone (AMH)
💡Leydig Cells
💡Sertoli Cells
💡Dihydrotestosterone (DHT)
Highlights
Embryology of the reproductive system is discussed in detail.
Primordial germ cells migrate to the gonadal ridge, forming the basis of reproductive development.
Three types of cells in the gonadal ridge are identified: primordial germ cells, mesothelial cells, and mesenchymal cells.
In males, mesothelial cells develop into seminiferous tubules, while in females, they form ovarian follicles.
Mesenchymal cells provide support, developing into Leydig cells in males and ovarian support stroma in females.
The genital and urogenital tracts originate from the intermediate mesoderm layer.
The Müllerian (paramesonephric) and Wolffian (mesonephric) ducts are key in the development of genital structures.
In the absence of hormonal input, the Müllerian duct develops into female reproductive structures.
The presence of the Y chromosome and SRY gene in males leads to the development of testes and male-specific structures.
Müllerian inhibiting factor (MIF) from Sertoli cells causes regression of the Müllerian duct in males.
Testosterone and dihydrotestosterone are responsible for the development of male external genitalia.
Clinical implications of testosterone deficiency are discussed, leading to underdeveloped male genitalia.
The indifferent genital tract's development into male or female structures is influenced by hormonal inputs.
The gubernaculum aids in the migration of testes from the abdomen to the scrotum.
The urogenital sinus contributes to the formation of the urinary bladder, urethra, and prostate in males.
In females, the urogenital sinus develops into the lower third of the vagina and urethra.
The genital tubercle develops into the glans penis in males and the glans clitoris in females.
The urogenital folds develop into the labia minora in females or the ventral aspect of the penis in males.
The labioscrotal swellings develop into the scrotum in males or the labia majora in females.
Recommended resources for further study include 'First Aid for the Basic Sciences' and 'Kaplan Step 1 Physiology'.
Transcripts
[Music]
okay hello everyone my name is ABD I'm
medical student at kingd aiz University
for Health Sciences and today we're
going to talk about embryology
specifically the development of the
reproductive system now this has been
requested by many students so without
further Ado let's get
started the first thing we want to talk
about is the Don ads okay so what's
going to happen over there so primordial
germ cells migrate to the gonado ridge
as you can see here the red dots over
here are the primordial germ cells okay
they're going to to migrate through the
vitaline duct and into the gonadal ridge
which is you can see at number 10 the
green part over here that's the gonado
ridge now in the gonado ridge we're
going to find three kinds of cells okay
primordial germ cells which just
migrated what are these going to give us
these are going to give us the future
gametes so spermatogonia and the oronia
in
females the the mesothelial cells over
here are going to give us the structures
that are going to Harbor and help in the
development of the primordial germ cells
so in males it's going to give us what
seminiferous tubules okay and females is
going to give us the follicles the
ovarian
follicles last kind of cells is the
mesenchimal cells these are supporting
cells remember the word support So in
males it's going to give us ladic cells
okay and in females it's going going to
give us what ovarian support stroma now
the genital ducts now before we get
started with the genital ducts I just
want to make a statement and I want you
to read this uh memorize this really
well the the whole genital tract
urogenital tract are made of which layer
ectoderm endoderm mm the right answer is
intermediate mism a lot of doctors like
to ask that they go back to the basics
where does all where do all this
structures come from intermediate
Miser okay now talking about the genital
ducts let's get let's get into details
genal ducts we have two ducts we have
the mifc duct over here and the
parameric duct they're also known as the
wolfian duct and the malarian duct I
suggest you memorize both names because
most exams put the mifc and parameric
although I like to memorize the wolfian
and malarian why because wolfian is
associated with the male genital ta
genital tract so wolf wolf and male you
can associate malarian is associated
with female genital ract now what do
these ducts give us or these tubes what
do they give us they give us the
internal genital structures so in males
the wolfian will give us epidemis vasin
and seminov vesicles and malarian is
going to give us in females uterus
Fallopian tubes and cervix and the upper
one/ thir of vagina okay now how do we
get male how do we get female what
happens we can't have both tubes one of
them has to go and one of them has to
stay okay so in situations where there
is no hormonal input no hormonal input
okay what's going to happen what's going
to happen is the malaran is going to
survive okay and stay alive it's going
to give us the uterus Fallopian tubes
cervix upper 1ir of vagina and the
wolfian duct is going to regress or die
no more epidemis no more vasin and no
more semino vesicles this what this what
happens in
normal physiology in females so in
females there there's not going to be
any hormonal input this is what's going
to happen Okay that's in females so what
about males what's going to happen in
males well in males in genetics they
Define male by having the Y chromosome
okay for example clim filter patient
they're going to have uh genetic
chromosomes of XX y since there's y they
put it they put they categorize them as
males okay why because the XY chromosome
or the Y chromosome has a region called
The Sex determining region the sry Y
okay this is going to encode many kind
of uh hormones and whatnot and will
result in after many kinds of sequences
into giving us ladic cells and CI cells
okay ctoi cells are going to give us MF
which is short for malarian inhibiting
Factor leic cells is going to give us
testosterone and dihydrotestosterone
dihydrotestosterone doesn't come
directly from LC cells but mostly from
testosterone or testosterone is
converted to dihydro testosterone
dihydro testosterone does not come
directly from ladic cells okay put that
in mind now genital
ducts this is what's going to happen in
males so we have ctoi cells gave us the
MF right malarian inhibiting Factor so
what's it's going to do it's going to
inhibit the malarian duct so no more
uterus no more Fallopian tubes no more
cervix and no more upper oneir of vagina
what about testosterone now usually we
said if there's no hormonal input wolf
induct will die but since we have
testosterone it's going to go there and
hey man stay with me keep it alive
Wolfie and duct will will stay alive and
will give us epidemis vas difference and
seminal vesicles okay now we talked
about MF we talked about testosterone
what about dihydro testosterone what
does that do that is responsible for the
external genitalia well mostly external
genitalia so it's going to give us the
prostate the penis and the scrotum okay
PPS for short now if there is no dihydro
testosterone no hormonal input what are
we going to have externally we're going
to have lebia Majora lebia minora a
female female genitals externally okay
now let's go a little bit clinical and
talk about uh something that doctors a
lot of a lot of times they brag about
okay which is sometimes in
patients they're not the testosterone
they are going to be
XY okay but their testosterone is not
functioning right either it's not coming
out of the the LC cells or The receptors
are not are not responding to the
testosterone something like that so the
testosterone effect is gone okay so
testosterone is not
working what's going to happen to the
wolfi induct it's going to die so no
more epidemis no more vas Defence and no
more seminal vesicles okay and of course
dihydrotestosterone comes from
testosterone we said that before so
since testosterone is not going to work
dihydrotestosterone is not going to work
so not so no more prostate no more penis
and no more scrotum we're going to have
labia majora laia minora and whatnot
however the MF comes from ctoi cells
okay so this function over here is going
to be all right nothing's wrong with
that okay so malarian param malarian
duct or the parameric duct is going to
regress okay so no more uterus no more t
no more Fallopian tubes no more cervix
and no more no more upper one/ third of
vagina so how would this patient present
usually present with female external
Alia normal but will come and say what
primary
Amara okay she's not having menar okay
so after tests you're going to find
after scans and and and tests like that
you're going to find what no she she
doesn't have uterus no fian tubes no
cervix no upper one third vagina okay
and you're going to find in well maybe
in the abdomen you're going to find
testes which uh say that she will you
she her chromosomes are XY however ever
the testosterone wasn't working
okay
now testes I'm not sure if they find
them in the abdomen or where in where
exactly in the body so but that's not
that's not really important the
important part is that testosterone
function is not working well either from
The receptors or from L cells or from
whatnot okay here is the P here's a
picture of indifferentiation genital
tract so we don't know if this is male
or female we still don't know here over
here what you see in number six this is
in different gonads it can either be
testes or can either be ovaries we don't
know the blue tubes over here the blue
ducts are the malarian ducts the pink
tubes are the wolfian ducts
okay what you see here number eight this
is the urogenital sinus okay this is
very important we'll talk about that
later what you see in the brown here the
brown two long lines is the gacul we're
going to talk about what the gab ulum
gives us later and over here in number
nine over
here is the labios scroto swellings okay
labor squirtel swelling okay over here
the
gacul will help us in many it will give
us also many structures we're going to
talk about uh for each male and female
will give us different structures gabac
is number seven okay let's talk about
males okay as we said in males what the
malarian duct is going to
regress the malarian duct is going to
die because we have MF it's going to
kill it and the the the Wolfie induct
will give us what will give us the
epidemis as you can see here the outer
part over here epidemis the vase
difference and the seminal vesicles okay
as you can see over here okay here now
the differentiated goads will become
what testes now since male we're going
to talk now became testes what about the
gab oraculum what does it do in males
well the testes are developed we all
know that the testes develop in the
abdomen but has to migrate down to the
scrotum that's where the gabaculine
comes in and says hey hey let me help
you out let me show you where the where
you have to go let me show you the way
okay so it helps in the migration of the
testes okay now the urogenital sence as
you see here what is that going to give
us that's going to give us the urinary
bladder okay it's going to give us also
the urethra okay the prostate gland and
the bulbo urethal gland okay that's in
males now just to draw a picture and you
can just imagine how how it will be
after migration now here we have the
semino vesicles over here with the sem
vesicles over here with uh they're going
to be attached to the vast differ now
the vast differ are going to follow the
epidemis which which is stuck to the
testes which just migrated downwards so
it's going to go where going to go up
and down followed down now this reminds
us of the real the the normal anatomy of
the male okay now let's talk about
females now in females what you see here
is undifferentiated picture after that
what's going to happen we said in
females there is no hormonal input so
with no hormonal input the malarian duct
will start to get closer to each other
okay closer and even more closer until
until it gives us some structures what
are the structures we said the uterus
Fallopian tubes the cervix and upper 1/3
of the vagina okay the wolfian duct we
said it's going to regress it's going to
to die okay as you see here okay what
about the gabac the gabac is going to
give us two important structures or two
important ligaments okay the first
ligament will be attached to the ovaries
see here was the differentiated gonads
now became ovaries so the ligament
attached to that will be the ovarian
ligament and the gabum is also going to
give us the round ligament okay so those
two structures now what about the ental
sinus the ental sinus we set in males it
gives us the urinary bladder the urethra
the prostate gland and the bulbo urethra
gland what about in females well there's
some things in common and some things
are different for example it also gives
us urinary bladder and the urethal
however in the females it gives us a
lower third of vagina urethal and Par
urethal glands and the greater
vestibular glands okay that those
structures and the UR urinary bladder
and the urethra okay now one thing one
note we I want to talk about before we
jump to the other slide which is in some
books you will see you would see that
the wolfian duct or the mifer duct will
give us structures that's related to the
kidneys for example it's going to give
it's going to give us the the uers the
renal pelvis the calluses and the
collecting tubules in both males and
females okay but that's starting to get
confusing that doesn't make sense
because we said in females the wolfian
duct dies what's going on well basically
in males and females over here down here
it's start to it's going to start to
give a little Mass a little piece of
tissue called the URC bud this UIC Bud
will then
grow and become the urer the renal
pelvis the cuses and the collecting
tubules okay so this tic Bud will happen
or will grow before the the wolfi induct
will will regress in females okay and of
course it will uh it will happen in
males because uh Wolfie duct doesn't
regress that so now that we talked about
internal structures now let's talk about
external
genitalia now what you see here in
number two over here is what we call the
the labio scrotal swelling okay now from
its name you can tell what it's going to
give us labios scroto so either Lao
labia majora or the scrotum in
males okay now number four here is what
we call what the urogenital folds okay
and number six inside is is the opening
of the urogenital sinus okay so here
number four the urogenital fold what is
what is this going to give us it's
either going to give us the labia minora
in
females or it's going to fuse and give
us what the ventral part of the the
penis and most of the penal urethra and
whatnot okay number three is what we
call the genital tubercle now the genal
tubercle I want you to associate it with
the word glands because it's going to
either give us the glands penis in males
or the glands clitoris in females
let's see here here we have it in colors
so let's start with the easy easy Parts
labios Scotto swelling which we see here
in purple okay it's either going to give
us the scrotum or the labia
majora okay the urethal folds are
urogenital folds what are they going to
give us they're going to give us either
the labia minora or they going to give
they're going to fuse and give us what
the vental aspect of the penis and most
of the urethra okay the the genital
tubercule I we said associated with the
word glands so either glands penis and
or glands
clitoris okay there are other structures
but I'm just I'm just stating the most
important ones that being said here I
left some of tables to show you which
structure uh gives out which structure
so here we have the ental sinus the mifc
duct and tubules and the parameric duct
you can just pause the video so you can
uh memorize what's on these tables this
is the other the continuing part of the
table we have the gentle tubercle your
gentle folds the labus scr lab scr folds
these are the actually the external
Galia mostly here are the references
that I useed for this video first aid
for the basic science is organ systems I
highly recommend uh highly recommend to
read from this book it gives uhe
especially when if you have problem with
the embryology of the genital tract most
of the most of the information of the
slides came from uh use from this book
and of course K us asmbly step one
physiology book I you know physiology
embryology what does that have to do
with it but they talk a little bit about
how how we have the ducts and how they
differentiate in uh in our in our bodies
if you have any questions or comments
here are here are the ways to reach me
thank you very much for for listening
and goodbye
[Music]
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