Gonads Flashcards
In females, the _____ duct regresses in response to a lack of testosterone.
Mesonephric (Wolffian)
In females, the ____ duct persists to form what 3 things?
The paramesonephric duct (Mullerian) persists to form the 1) uterus, 2) fallopian tubes, and 3) superior 1/3 of vagina
Around week 5, the gonadal ridge is formed and stimulated to differentiate into the indifferent gonad under the genetic influence of what 2 genes?
1) Wilms Tumor (WT-1)
2) Steroidogenic factor-1 (SF-1)
The WT-1 and SF-1 genes cause primordial germ cells to migrate into the mesenchyme to form ____ ___ ___ to form the indifferent gonad.
Primary sex cords
The indifferent gonad has an outer ___ and an inner ____. Which layer persists for females? Males?
Outer cortex = forms the Ovary
Inner medulla = forms the testicle
(Medulla in Men; The ‘O in cOrtex is for Ovary)
The indifferent gonad –> testicle is influenced by what two genes?
1) SOX-9 (SRY-related HMG box-9)
2) SRY (Sex-determining Region Y)
The indifferent gonad –> ovary in influences by what two genes?
1) Wnt-4 (Wingless-related MMTV integration site 4)
2) DAX-1 (Dosage-sensitive sex-reversal adrenal hypoplasia congenital region of the X chromosome gene 1)
The SRY gene is located on what chromosome?
Yp11.3 (short arm of Y chromosome)
The primary sex cords of the indifferent gonad in males condense into the gonadal ____ to form the rete testis and seminiferous cords.
condense into the gonadal Medulla
What encases the seminiferous cords to form the testicle?
The tunica albuginea
The seminiferous cords eventually become what 3 things?
1) seminiferous tubules (which lack a lumen until puberty)
2) tubular recti
3) rete testes
This structure develops between the seminiferous tubules and secretes testosterone and androstenedione by the 8th week.
Interstitial cells of Leydig
This cell type lines the seminiferous tubules and secretes ___ ___ ___ to cause the paramesonephric ducts to regress.
Sertoli cells; secrete Mullerian Inhibiting Substance (MIS)
Under the influence of testosterone and MIS, the mesonephric ducts migrate caudally to form what structures?
Seminal vesicles Ejaculatory ducts Epididymis Efferent ductules Ductus deferens
“SEEED”
The ____ ____ from the epididymis outpouches to form a connection with the ___ ___ and makes the first genitourinary connection during the 9th week.
The efferent ductules connects with the rete testis
i.e the mesonephric duct connects to the gonads
By 8 months, the testicle descends into the scrotum with guidance from the ____
Gubernaculum
When descending through the inguinal canal, the testicle takes a piece of peritoneum (aka the ___ ___) which forms what structure around the testicle?
AKA the processus vaginalis, which forms the Tunica vaginalis
If the processus vaginalis remains patent, what may form?
Communicating hydroceles (peritoneal fluid may flow into and surround the testicle)
- Also has increased risk of congenital inguinal hernia
- Majority resolve spontaneously
What is the default sex? Explain.
Female. If testosterone not secrete by testes, the a definitive ovary will form. The sex cords will join the indifferent gonadal medulla and regress, while the cortex will proliferate into cortical cords into the underlying mesenchyme
The cortical cords of female development will divide into isolated cell clusters known as ___ ___ at around 4 months.
Primordial follicles (oogonia and follicular cells)
Oogonia replicate via ____ to produce more primordial follicles
Mitosis
Primordial follicles partially undergo ____ to form what?
Meiosis; form into primary oocytes
Females are born with ~20 million primary oocytes which are arrested in what stage of meiosis until menarche?
Prophase 1
