L12. Embryology - Development of the Reproductive System
40 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What does the hymen separate in the female reproductive system?

  • The ovaries from the fallopian tubes
  • The vaginal canal from the urogenital sinus (correct)
  • The urethra from the vagina
  • The cervix from the uterus

During which weeks does the indifferent stage of external genital development occur?

  • Weeks 3-6 (correct)
  • Weeks 11-14
  • Weeks 7-10
  • Weeks 1-2

What is formed by the cranial half of the cloacal folds during development?

  • The genital tubercle
  • The anal folds
  • The labial majora
  • The urethral folds (correct)

What is the role of androgens in the development of external genitalia?

<p>They promote the elongation of the genital tubercle (D)</p> Signup and view all the answers

What are the structures that lateral to the cloacal folds give rise to in males and females?

<p>Scrotum and labial majora (C)</p> Signup and view all the answers

What is the significance of the SRY gene in gonadal development?

<p>It promotes the differentiation of the indifferent gonad into a testis. (C)</p> Signup and view all the answers

During the development of the ovary, what happens to the primitive medullary sex cords?

<p>They regress and contribute minimally to the ovary. (D)</p> Signup and view all the answers

What do the contents of the sex cords develop into within the testis?

<p>Rete testis and seminiferous tubules. (A)</p> Signup and view all the answers

What is the fate of primordial germ cells during ovarian development?

<p>They undergo extensive mitosis to contribute to follicle formation. (C)</p> Signup and view all the answers

What is the role of the tunica albuginea in gonadal development?

<p>It thickens in males and thinly develops in females. (C)</p> Signup and view all the answers

Which structure develops from the primitive sex cords in the testis?

<p>Rete testis. (B)</p> Signup and view all the answers

What is the embryological origin of the interstitial cells of Leydig?

<p>They arise from the mesoderm adjacent to the sex cords. (D)</p> Signup and view all the answers

At what week of gestation does sexual differentiation in the developing fetus begin?

<p>7th week (C)</p> Signup and view all the answers

Which of the following structures is formed due to SRY expression?

<p>Testis (C)</p> Signup and view all the answers

What is the result in the absence of the Y chromosome during fetal development?

<p>Formation of female external genitalia (A)</p> Signup and view all the answers

During which week do primordial germ cells begin their migration to the endoderm of the yolk sac?

<p>3rd week (D)</p> Signup and view all the answers

What is referred to as the 'Indifferent stage' of sexual development?

<p>Period when male and female genitalia are indistinguishable (C)</p> Signup and view all the answers

Which structure develops from the prostate during male development?

<p>Ejaculatory duct (B)</p> Signup and view all the answers

What begins to develop in the 5th week of gestation related to the gonads?

<p>Longitudinal genital ridges (A)</p> Signup and view all the answers

What is the developmental fate of primordial germ cells by the 5th week?

<p>They reach the primitive gonads (D)</p> Signup and view all the answers

Which of the following structures does NOT develop due to SRY expression?

<p>Ovary (A)</p> Signup and view all the answers

What is the main role of the mesoderm in the formation of the uterus?

<p>It provides smooth muscle layers for the myometrium. (A)</p> Signup and view all the answers

Which part of the urogenital structure is formed from the sinovaginal bulbs?

<p>Inferior 2/3 of the vagina (D)</p> Signup and view all the answers

What does the recanalization process form during development?

<p>Vagina (D)</p> Signup and view all the answers

At what developmental stage does the recanalization process complete?

<p>Around the time of birth (A)</p> Signup and view all the answers

Which structure is primarily associated with the distal part of the paramesonephric ducts?

<p>Vagina (C)</p> Signup and view all the answers

Which parts of the vagina derive from different developmental structures?

<p>Superior 1/3 from paramesonephric ducts and inferior 2/3 from sinovaginal bulbs (C)</p> Signup and view all the answers

What is the primary process that allows the growth of sinovaginal bulbs?

<p>Growth signaling from the urogenital membrane (C)</p> Signup and view all the answers

What layer contributes to the outer muscular layers of the uterine tubes?

<p>Mesoderm (C)</p> Signup and view all the answers

What is the significance of the cranial end of the fused sinovaginal bulbs?

<p>Develops into the superior part of the vagina (A)</p> Signup and view all the answers

What structures are formed from the differentiation of the paramesonephric duct?

<p>Fimbriae and uterine tubes (A)</p> Signup and view all the answers

What role does the SRY transcription factor play in the development of the urogenital system?

<p>Inhibits the synthesis of the FGF9 factor (C)</p> Signup and view all the answers

Which option correctly describes the composition of the paramesonephric duct?

<p>It initially has three distinct parts. (B)</p> Signup and view all the answers

What does the absence of the FGF9 factor lead to in female embryonic development?

<p>Regression of the mesonephric duct (A)</p> Signup and view all the answers

Where can remnants of the mesonephric ducts be found in adult females?

<p>Within the mesovarium (A)</p> Signup and view all the answers

What is the function of the paramesonephric tubercle in embryonic development?

<p>To anchor the caudal part of the duct (C)</p> Signup and view all the answers

What factors influence the differentiation of the paramesonephric duct?

<p>Synthesis of the FGF9 factor (C)</p> Signup and view all the answers

Which part of the paramesonephric duct fuses with its counterpart?

<p>Caudal part anchored at the paramesonephric tubercle (B)</p> Signup and view all the answers

In female development, which of the following is NOT a result of the absence of SRY transcription factor?

<p>Development of a functioning ovary (A)</p> Signup and view all the answers

Which anatomical relationship exists between the paramesonephric duct and the mesonephric duct?

<p>The paramesonephric duct typically crosses the regressing mesonephric duct (B)</p> Signup and view all the answers

Flashcards

SRY Gene's Role

The Y chromosome contains the SRY gene, which triggers the development of male characteristics. This gene leads to the differentiation of the indifferent gonad into a testis, ultimately influencing the development of both internal and external male reproductive organs.

Indifferent Gonad Stage

The initial stage of gonadal development is called the 'indifferent' stage. It's characterized by a common structure—the genital ridge—that can potentially develop into either testes or ovaries.

Primordial Germ Cell Origin

Primordial germ cells, the earliest stage of reproductive cells, originate from the yolk sac. They migrate to the genital ridge and initiate the formation of the indifferent gonad.

Primitive Sex Cords

The indifferent gonad develops primitive sex cords, which are the initial structures that contribute to either the future testes or ovaries. These cords play a pivotal role in sex determination.

Signup and view all the flashcards

Testis Differentiation

The differentiation of the indifferent gonad into a testis relies on genetic signals—primarily originating from the Y chromosome. This triggers the development of male sexual characteristics.

Signup and view all the flashcards

Medullary Cord Development

In the developing testis, the primitive sex cords evolve into medullary cords, which further develop into critical structures for sperm production: the rete testis and testis cords.

Signup and view all the flashcards

Testis Cord Transformation

The testis cords, derived from the medullary cords, eventually transform into seminiferous tubules. These tubules are the crucial site of sperm production within the adult testes.

Signup and view all the flashcards

What is the hymen?

A thin membrane that separates the vaginal lumen from the urogenital sinus during fetal development. Derived from the urogenital membrane, it typically opens via recanalization before birth.

Signup and view all the flashcards

What is the indifferent stage of external genital development?

The stage in fetal development (weeks 3-6) where the external genitalia of male and female embryos are indistinguishable. Structures like the cloacal folds, genital tubercle, and genital swellings form but don't show sex-specific characteristics.

Signup and view all the flashcards

What are the cloacal folds?

The paired folds that emerge from the cloacal membrane during the indifferent stage. They later differentiate into the urethral and anal folds.

Signup and view all the flashcards

What is the genital tubercle?

The prominent midline swelling that forms at the cranial end of the cloacal folds. It will later develop into the penis or clitoris.

Signup and view all the flashcards

What are the genital swellings?

The pair of swellings that appear lateral to the cloacal folds during the indifferent stage. They will later develop into the scrotum in males and the labia majora in females.

Signup and view all the flashcards

What is the SRY gene?

A gene on the Y chromosome that initiates the development of male characteristics, such as testes, prostate, and external genitalia.

Signup and view all the flashcards

What is the indifferent gonad?

The initial stage of gonadal development before the differentiation into male or female.

Signup and view all the flashcards

What are primordial germ cells?

Specialized cells that will eventually develop into eggs (female) or sperm (male).

Signup and view all the flashcards

What is sexual differentiation?

The process by which the indifferent gonad develops into either testes or ovaries, influenced by the presence or absence of the Y chromosome.

Signup and view all the flashcards

When does sexual differentiation begin?

The 7th week of gestation is when the indifferent gonad starts to develop into either testes or ovaries.

Signup and view all the flashcards

What is the migration of primordial germ cells?

The migration of primordial germ cells from the yolk sac to the gonad.

Signup and view all the flashcards

What is male development?

The development of male characteristics in the presence of the SRY gene, including testes, prostate, and external genitalia.

Signup and view all the flashcards

What is female development?

The development of female characteristics in the absence of the SRY gene, including ovaries, uterus, and external genitalia.

Signup and view all the flashcards

What is intersex?

The condition in which a fetus does not develop either male or female characteristics, leading to ambiguous genitalia.

Signup and view all the flashcards

Myometrium

The muscular layer of the uterus, formed from mesoderm.

Signup and view all the flashcards

Paramesonephric Ducts

Paired tubes that develop into the female reproductive tract, including the uterus, fallopian tubes, and upper vagina.

Signup and view all the flashcards

Urogenital Membrane

A membrane that forms the floor of the pelvic cavity and contributes to the development of the vagina.

Signup and view all the flashcards

Sinovaginal Bulbs

A pair of structures that arise from the mesoderm of the urogenital membrane and contribute to the formation of the vagina.

Signup and view all the flashcards

Recanalization

The process of a tubular structure becoming hollow again after being temporarily solid.

Signup and view all the flashcards

Superior 1/3rd of Vagina

The upper part of the vagina, formed from the fused paramesonephric ducts.

Signup and view all the flashcards

Inferior 2/3rds of Vagina

The lower part of the vagina, formed from the sinovaginal bulbs.

Signup and view all the flashcards

Cervix of the Uterus

The point where the cervix of the uterus connects to the vagina.

Signup and view all the flashcards

Embryonic Development

The process of development in the body from conception to birth.

Signup and view all the flashcards

Mesoderm

The mesoderm is a germ layer that gives rise to various tissues and organs, including the muscular layers of the uterus and vagina.

Signup and view all the flashcards

SRY gene absence and female development

The absence of the SRY gene, a key determinant of male development, leads to the suppression of FGF9 synthesis and release, preventing the mesonephric duct from developing in females.

Signup and view all the flashcards

Paramesonephric duct: Anatomy and parts

The paramesonephric duct, which develops into female reproductive structures, initially has distinct parts: a cranial vertical section connected to the abdominal cavity, a horizontal section crossing the regressing mesonephric duct, and a caudal section that fuses with its counterpart and attaches to the urogenital membrane.

Signup and view all the flashcards

Paramesonephric duct - differentiation

The paramesonephric duct differentiates into various female reproductive structures: the fimbriae, uterine tubes, uterus, cervix, and the upper region of the vagina.

Signup and view all the flashcards

Mesonephric duct regression in females

The mesonephric duct, which would normally develop into male reproductive structures, regresses in the female embryo due to the absence of the SRY gene and FGF9 signaling.

Signup and view all the flashcards

Mesonephric duct remnants in females

Remnants of the mesonephric duct may persist in females, forming structures like the epoophoron, paroophoron, and Gartner's cysts, which are usually asymptomatic.

Signup and view all the flashcards

Epoophoron and paroophoron

The epoophoron and paroophoron are remnants of the mesonephric duct found within the mesovarium, a structure that suspends the ovary from the uterine tube.

Signup and view all the flashcards

Gartner's cyst

Gartner's cysts are remnants of the mesonephric duct located in the wall of the vagina. They are usually benign and asymptomatic.

Signup and view all the flashcards

Paramesonephric tubercle

The paramesonephric tubercle is a small elevation of tissue at the base of the urogenital membrane, where the caudal portion of the paramesonephric duct attaches.

Signup and view all the flashcards

Summary: Female reproductive system development

The absence of SRY gene and FGF9 signaling leads to the regression of the mesonephric duct, while the paramesonephric duct differentiates into female reproductive structures. This process is essential for normal female development.

Signup and view all the flashcards

Study Notes

Development of the Male and Female Reproductive System

  • Sex determination is dependent on the Y chromosome and SRY gene expression.
  • Primordial germ cells originate from the epiblast and migrate to the yolk sac.
  • Indifferent gonad development occurs during weeks 4-7.
  • Testis development involves SRY gene expression, signalling events and the differentiation of the medullary cords into seminiferous tubules.
  • Ovary development involves the differentiation of cortical cords into follicular cells, and the fate of the medullary cords.

Differentiation of Gonads

  • The indifferent gonad develops into either testes or ovaries.
  • Male development (XY) is driven by SRY, which determines formation of testes.
  • Female development (XX) is driven by the absence of SRY, which determines the formation of ovaries.

Genital Duct Formation

  • Mesonephric (Wolffian) ducts give rise to the male duct system (e.g., vas deferens, epididymis, seminal vesicles, ejaculatory ducts).
  • Paramesonephric (Müllerian) ducts become the female duct system (e.g., uterine tubes, uterus, upper vagina) and, in males, degenerate due to anti-Müllerian hormone (AMH).
  • The presence/absence of SRY and AMH influences the development of each system.

External Genitalia Development

  • Male external genitalia development relies on androgens. It begins with the development of the genital tubercle. This expands into the penis, with the urethral groove and raphe formation. The scrotal swellings develop and fuse.
  • Female external genitalia development occurs after the sexual differentiation, with the formation of the urethral folds to become the labia minora. The genital tubercles form the clitoris and the genital swellings form the labia majora.

Development of the External Genitalia

  • The External Genitalia formation begins at week 4.
  • The Genital tubercle determines the development for the penis and clitoris
  • The Genital folds develop into Urethra in the male and clitoris in female.
  • SRY and AMH are key factors in this stage.

Descent of the Testes

  • The gubernaculum guides the testes from the abdominal cavity.
  • The processus vaginalis, internal and external abdominal oblique, and transversus abdominis muscles are involved in the descent.
  • The tunica vaginalis is a remnant of the processus vaginalis.

Clinical Relevance

  • Uterine/Vaginal defects can occur due to incomplete fusion or atresia of the ducts.
  • Male genitalia defects like hypospadias (incomplete urethral opening) and epispadias (abnormal urethral opening), can affect urinary function.
  • Indirect inguinal hernias can result from incomplete closure of the processus vaginalis.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Development of the Male and Female Reproductive System 2024-2025 PDF

Description

This quiz covers the essential aspects of male and female reproductive system development, including sex determination, gonad differentiation, and genital duct formation. It explores the role of the Y chromosome and SRY gene in testis development alongside the processes leading to ovary formation. Test your knowledge on this fundamental biological topic.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser