Embryology of Female Reproductive System

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary origin of the epithelial lining of the vagina?

Neural crest origin

Endodermal origin (correct)

Ectodermal origin

Mesodermal origin

What do the sinovaginal bulbs develop into during vaginal formation?

Paramesonephric ducts

Ureteral ducts

Mesonephric remnants

Solid vaginal plate (correct)

Which of the following structures does NOT develop from mesoderm around the cloacal membrane?

Glans clitoris

Phallus

Labia minora (correct)

Labia majora

Which remnant of the paramesonephric duct can form cysts?

Hydatid cyst of Morgagni Signup and view all the answers

What is the fate of the mesonephric (Wolffian) ducts in the female?

They degenerate after kidney formation. Signup and view all the answers

What is the role of primordial germ cells in the development of primary sex cords?

They migrate from the yolk sac to the gonadal ridge and are incorporated into primary sex cords. Signup and view all the answers

What structure develops from the cranial portions of the paramesonephric ducts?

Uterine tubes Signup and view all the answers

What is the function of the gubernaculum in ovarian development?

It forms the round ligament and stabilizes the ovaries during descent. Signup and view all the answers

Which of the following is NOT a characteristic of secondary sex cords?

They develop into the rete ovarii. Signup and view all the answers

What is derived from the mesoderm during the development of female reproductive structures?

Simple squamous cells of primordial follicles and ovarian connective tissue stroma Signup and view all the answers

What major structure does the uterovaginal primordium develop into?

The uterus and cervix Signup and view all the answers

Which statement is true regarding the descent of the ovaries?

Descent is influenced by the growth of the upper abdomen relative to the pelvic region. Signup and view all the answers

What marks the degeneration of the rete ovarii during follicle development?

Development of secondary sex cords Signup and view all the answers

At what stage does the indifferent embryo begin phenotypic sexual differentiation?

Week 7 Signup and view all the answers

Which gene is associated with determining the male phenotype?

SRY gene Signup and view all the answers

What factor is produced by Sertoli cells that inhibits Müllerian duct development?

MIF Signup and view all the answers

Which of the following events occurs last in the sequence of phenotypic sexual differentiation?

Recognition of external genitalia Signup and view all the answers

What is the main outcome of the presence of TDF in the indifferent embryo?

Development of male phenotype Signup and view all the answers

During which week can recognizable male or female characteristics of the external genitalia be identified?

Week 12 Signup and view all the answers

Which of the following components are included in the indifferent embryo?

Gonads and primordia of external genitalia Signup and view all the answers

From which embryonic structure does the gonadal ridge develop?

Urogenital ridge Signup and view all the answers

Study Notes

Embryology of the Female Reproductive System

The embryo's sex is determined at fertilization (46, XX or 46, XY).
In the first 6 weeks, the embryo is sexually undifferentiated and genetically distinct male and female embryos are phenotypically indistinguishable.
By the 7th week, phenotypic sexual differentiation begins.
By the 12th week, external genitalia characteristics are recognizable.
By the 20th week, complete phenotypic differentiation is achieved. This is determined by the SRY gene (sex-determining region Y).
The SRY gene on chromosome Y (Yp11.3) codes for a sex-determining region Y protein (TDF).
Testes development leads to Leydig cells differentiating to produce testosterone and Sertoli cells producing Müllerian-inhibiting factor (MIF).
In the presence of TDF, testosterone, and MIF, the embryo develops into a male.
In the absence of these factors, the embryo develops into a female.

Components of the Indifferent Embryo

Gonads
Genital ducts
Primordia of external genitalia.
Phenotypic sexual differentiation starts with the gonads then the genital ducts and finally the external genitalia.

Development of the Gonads

The intermediate mesoderm forms a urogenital ridge along the dorsal body wall.
The coelomic epithelium and the underlying mesoderm of the urogenital ridge form the gonadal ridge.
Primary sex cords develop from the gonadal ridge.
These incorporate primordial germ cells that have migrated into the gonad from the yolk sac wall.

Development of the Ovaries

Primary sex cords extend into the medulla and become the rete ovarii (which degenerates later).
Secondary sex cords develop, incorporating primordial germ cells as a tunica albuginea.
These secondary sex cords break down into primordial follicles containing primary oocytes and simple squamous cells.
Primary oocytes come from primordial germ cells.
Ovarian connective tissue stroma comes from mesoderm.)

Relative Descent of the Ovaries

Ovaries initially develop in the abdomen but later descend into the pelvis due to disproportionate growth in the upper abdomen compared to pelvic area.
Gubernaculum, a fibrous tissue, extends from the ovary to the uterus and forms the ovarian and round ligaments.
The peritoneum forms the processus vaginalis along the gubernaculum, becoming obliterated in the female during development.

Development of the Genital Ducts

Paramesonephric (Müllerian) ducts develop as mesodermal invaginations from the lateral surface of the urogenital ridge.
The cranial portions of these ducts become uterine tubes.
The caudal sections fuse to form the uterovaginal primordium and the broad ligament.
The uterovaginal primordium develops into the uterus, cervix and superior one-third of the vagina.
The paramesonephric ducts enter the dorsal wall of the cloaca and induce sinovaginal bulb development.
Fused sinovaginal bulbs form the solid vaginal plate, which canalizes into the inferior two-thirds of the vagina.
The epithelial lining of the entire vagina is endodermal in origin.

Mesonephric (Wolffian) Ducts

These ducts develop in the female as part of the urinary system, playing a role in the development of the metanephric kidney.
However, in the female, these ducts degenerate following metanephric kidney formation.

Vestigial Remnants/Cysts

Remnants of the mesonephric and paramesonephric ducts may form cysts.
Examples mentioned include cysts of Morgagni (1), Kobelt (2), epoophoron (3), paroophoron (4), and Gartner (5).

Development of External Genitalia Primordia

Proliferation of mesoderm around the cloaca causes overlying ectoderm to elevate forming the phallus, urogenital folds, and labioscrotal swellings.
Phallus becomes the clitoris with glans, corpora cavernosa, and vestibular bulbs.
Urogenital folds form the labia minora.
Labioscrotal swellings become the labia majora and mons pubis.

Studying That Suits You

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

Description

Explore the fascinating process of embryonic development concerning the female reproductive system. This quiz covers the stages from fertilization to complete sexual differentiation, highlighting the crucial role of the SRY gene and various hormonal influences. Test your knowledge on how genetic factors determine the pathway of sexual identity during embryogenesis.