Lecture 1: Female Reproductive Embryology Flashcards
What compose the genital structures in embryonic life?
- Gonads
- Internal ductwork
- External Genitalia
Up until week 7 all are similar in both sexes
Both sides (of gonads) have both ducts in embryology
What is the Wolffian Duct? What does it develop into?
The Masculine Duct Aka The MESONEPHRIC duct Develops into i. seminal vesicles ii. vas deferens iii. epididymis
What is the Mullerian Duct? What does it develop into?
The Feminine Duct AKA the PARAmesonephric duct Develops into i. Fallopian tubes ii. uterus iii. vagina
What factors do females need to develop female genitalia?
Estrogen
Males on the other hand need 4 factors…more high maintenance
What factors do males need to develop male genitalia?
- Testis Determining Factor (TDF)
- Mullerian Inhibiting Factors
- Testosterone
- Dihydrotestosterone
Must be released in order
More shit = more ways to fuck up
Also makes female the default gender
What is the mesonephros? Significance
Part of the mesoderm that forms an early kidney
Mesonephric duct has already induced kidney formation and forms the URETER in both sexes
-intermediate mesoderm
What does testosterone do to the mesonephric duct?
It makes the ureter as well as male genitalia
Lack of testosterone (e.g. estrogen only) means that mesonephric duct degenerates
What is the genital ridge?
The precursor to the gonads
Originally consists mainly of mesenchyme
What is the major transformative force to induce genital ridge to either male or female gonad?
The Primordial germ cells
Where do primordial germ cells develop? Significance?
In the Yolk Sac PGCs migrate into the genital ridge Induces development of either testis or ovary PGC Yes TDF Sry gene, Y chromosome PGC No Y No TDF Females
What does the arrival of PGCs or germs cells form?
Stimulates the formation of the PRIMITIVE SEX CORDS (which can become either testis cords or cortical cords)
Forms the Supporting cells in the gonads
What does SRY gene mean? Significance?
Sex Determining Region of the Y chromosome
Once expressed it makes the support cells turn into Sertoli Cells
What are the Germ, Supporting and Sex-hormone producing cells of male vs. female?
Male i. sperm ii. Sertoli iii. Leydig Female i. egg ii. Follicle Cell = granulosa cell iii. Theca cell
What happens to germ cells in females?
The germcells start gametogenesis
RIGHT AWAY and arrest in M1
Then induce formation of granulosa/follicular cells
Why do Males inhibit gametogenesis?
Temperature is not right
What are the precursors of the supporting cells of the gonad?
Coelomic Epithelium
What is Coelomic epithelium?
Precursor to supporting cells of gonad
What are the precursors of the sex-hormone producing cells?
Mesodermal Stromal cells
What are mesodermal stromal cells?
Precursor to sexhormone producing cells (leydig or theca)
Why do males have a continuous duct system while females don’t have a continuous duct system?
Mesonephric duct is attached to gonad
Paramesonephric duct are next to mesonephric duct + gonad so it will NOT be continuous
What happens when ducts are subjected to estrogen?
Mesonephric ducts degenerate
Paramesonephric ducts partially fuse
ALL FEMALE GERM CELLS begin gametogenesis to prophase of M1
At birth, ovary contains just primary oocytes arrested in prophase of M1
What is the significance of fusion of paramesonephric ducts?
Inferior paramesonephric ducts FUSE to form the
i. uterus ii. cervix iii. upper part of the vagina
Where does the lower part of the vagina come from? Significance?
Urogenital sinus….ENDODERM
Vagina has DUAL embryonic origin
Top part mesoderm
Bottom part endoderm
What does the urogenital sinus give rise to?
Bladder and urethra in BOTH sexes
What does the fusion of paramesonephric duct bring?
Bring together a peritoneal fold that will form the BROAD LIGAMENT
Creates two peritoneal compartments
Uterine cavity is created by resorption after PM duct fusion
Ovary goes from facing anteriorly to facing posteriorly because PM has to move to the midline
What is the broad ligament?
Peritoneal covering of the 1. uterus (mesometrium) 2. uterine tubes (mesosalpinx) 3. Ovaries (mesovarium) Shower curtain the drapes this shit
What is the water under the bridge relationship in females?
Ureter goes under OVARIAN ARTERY
What is the significance of the pelvic diaphragm?
What kegel exercises do to strengthen vagina
What are the different abnormalities of PM fusion?
- Bicornuate uterus (two uteri and one vage)
- Uterus Didelphys with double vagina
- Uterus arcuatus (indentation on top)
- Uterus bicornis unicollis (two horns, one separated)
- Atresia of cervix (uterus and vagina are not connected)
- Atresia of vagina (bottom part of vagina occluded)
What are the three areas of the external genitalia of the female?
- Glans area
- clit in females
- glans of penis in males
- Genital Swelling
- labia majora
- scrotum in males
- Urogenital fold
- labia minora
- shaft of penis
When does Meiosis I resume?
During ovulation
Will arrest in METAPHASE of M2
What is the mesosalpinx?
Part of the BROAD LIGAMENT
Stretches from ovary to uterine tube
What is the mesovarium?
Part of BROAD LIGAMENT
Covers the ovaries
What is the mesometrium?
Constitutes the majority of broad ligament
Covers the ureter
Forms the mesentery of the uterus
