Male vs. Female Differentiation Flashcards
How would females develop?
Typically this is the default in the absence of SRY from the Y chromosome. In the absence of SRY, AMH is not produced by male sertoli cells and the mullerian structures do not regress. When this happens mesonephric ducts regress and paramesonephric ducts develop into the female genital tract (fallopian tubes, uterus, and upper vagina (not the ovaries!)). The lower vagina forms from an invagination of the perineal body
NOTE: Mayer-Rokitansky-Kuster Hauser Syndrome is mullerian agenesis and may present as primary amenorrhea (due to a lack of uterine development) in females with fully developed 2ndary sexual characteristics (functional ovaries)
What do the Mesonephric (wollfian) ducts form in males in the presence of SRY, AMH (from sertoli cells), and testosterone (from Leydig cells)?
SEED
Seminal vesicles, epididymis, ejaculatory duct, and Ductus (vas) deferens
NOT the prostate
Again, what determines male vs female differentiation?
SRY on the Y chromosome that produces testis-determining factor causes the testes to produce sertoli and leydig cells
What do sertoli cells produce that cause regression of the paramesoneprhic ducts (mullerian)?
AMH
What do Leydig cells produce that promote the proliferation of the wolffian ducts into the INTERNAL male genitalia (except the prostate)?
testosterone
What stimulates formation of the external male genitalia and the prostate?
DHT
How is DHT made from testosterone in the periphery?
5a-reductase (inhibitors include finasteride and dutasteride)
NOTE: 5a-reductase deficiency causes ambiguous external genitalia until puberty
What would happen if you had SRY present, but no sertoli cells?
The lack of AMH would cause the formation of BOTH male and female internal genitalia with only male external genitalia and a prostate from DHT (b/c leydig cells would still make testosterone)
What are the derivatives of the genital tubercle?
the glans penis and corpus cavernosum/spongiosum in the presence of DHT and the glans clitoris and the vesitcular bulbs in the presence of estrogen
What are the derivatives of the urogenital sinus?
Copwer glands and a prostate in the presence of DHT and
Bartholin glands and urethral/paraurethral glands in the presence of estrogen
What are the derivatives of the urogenital folds?
the penile urethra in the presence of DHT and the labia minora in the presence of estrogen
What are the derivatives of the labiosacrotal swelling?
the scrotum or the labia majora
What is hypospadias?
The abnormal opening of the urethral meatus in the inferior (ventral) side of the penis due to failure of urethral folds to close
Hypo= below
What are consequences of hypospadias?
UTIs
What is epispadias?
Abnormal opening of the penile urethra on the superior (dorsal) side of the penis due to faulty positioning of the genital tubercle)
If you have Epispadias, you might hit your Eye when you pEE
What is a potential consequence of epispadias?
extrophy of the bladder
What structures aid in the descent of the testes?
The gubernaculum (band of fibrous tissue), which anchors the tests within the scrotum in men
processus vaginalis (evagination of peritoneum) which forms the tunica vaginalis in men and is obliterated in women
What are the remnants of the gubernaculum in women?
ovarian ligament and round ligament of uterus
What is the venous drainage of the gonads?
left ovary/testis goes to the left gonadal vein, to the left renal vein, and then to the IVC while the
right ovary/testis drains to the right gonadal vein, and then directly to the IVC
Why is varicocele more common in the left side?
Because the left gonadal vein enters the left renal vein so sharply
What is the lymph drainage of the ovaries/testes?
para-aortic lymph nodes
What is the lymph drainage of the distal 1/3 of the vagina/vulva/scrotum?
superficial inguinal nodes
What is the lymph drainage of the proximal 2/3 of the vagina and uterus?
obturtor, external iliac, and hypogastric nodes
What is the role of the suspensory ligament of the ovaries?
connects the ovaries to the lateral pelvic wall
What is contained with the suspensory ligament of the ovaries?
ovarian vessels
What is the role of the cardinal ligament?
connect the cervix to the side wall of the pelvis
Whats contained with the cardinal ligament?
uterine vessels (ureter at risk of injury during ligation of uterine vessels in a hysterectomy)
water under the bridge
What ligament connects the uterine fundus to the labia majora?
the round ligament of the uterus (remember this is derived from the gubernaculum)
What structures does the round ligament contain?
Artery of Sampson
What are the components of the broad ligament?
mesosaplinx, mesometrium, and mesovarium
What does the ligament of the ovary do?
connects the lower pole of the ovary to the lateral uterus (no structures run in this ligament)
remember this is also a deriv of the gubernaculum
Describe the epithelium of the female genital tract?
Simple cuboidal in the ovaries,
simple columnar in the fallopian tubes to the endocervix
Stratified squamous in the exocervix to the vagina
What are the parts of the male reproductive tract?
Sperm is made in the seminiferous tubules, to the rete testes, and then sent to the epididymis, then to the ejaculatory duct where the seminal vesicles join and secrete fructose and prostaglandins, and then through the urethra and out the penis
