L20 – Development of the Male and Female Reproductive System Flashcards
Tract the structures from Testis to Penis?
Testis > Epididymis > Ductus Vas Deferens > Ejaculatory duct > accessory sec glands > urethra > penis
List the accessory sex glands in male and function?
Prostate, seminal vesicles, bulbourethral gland
Production of secretions (semen)
Function of epididymis?
Reservoir for sperm (sperm maturation)
List the structures from ovary to labia majora?
Ovary > uterine tube > uterus > vagina + greater and lesser vestibular glands > Labia majora and minora + clitoris
Summarize the differentiation of germ layers in the Indifferent stage of gonad development?
Endoderm:
Primordial germ cells migrate from yolk sac
Mesoderm:
Gonadal ridge (part of urogenital ridge) forms from intermediate mesdoerm, contains:
a) Mesenchymal tissue
b) epithelial tissue: gonadal cords and mesodermal epithelium
Summarize the testis** structures formed from bipotential/ indifferent stage of gonad development?
Primordial germ cells (endoderm)»_space; spermatogonia
Gonadal ridge (mesoderm)»_space;Seminiferous cords and interstitial cells
Mesodermal epithelium»_space; Mesothelium
Summarize the ovary** structures formed from bipotential/ indifferent stage of gonad development?
Primordial germ cells»_space; oogonia
Gonadal ridge»_space; Primordial follicles and intersitital cells
Mesodermal epithelium»_space; mesothelium
Summarize the mature structures in testis formed from differentiated gonads?
Spermatogonia»_space; spermatozoa
Seminiferous cords and intersitital cells»_space; Tunea albuginea, Interlobular septa, Mediastinum testis, Sertoli and Leydig cells
Mesothelium»_space; visceral layer of tunica vaginalis
Summarize the mature structures in ovaries formed from differentiated gonads?
Oogonia»_space; ovum
Primordial follicles»_space; granulosa and theca cells
Interstitial cells»_space; tunica albuginea and other interstitial cells
Mesothelium»_space; germinal epithelium
Describe the formation of upper and lower genital ducts during indifferent stage?
Upper:
Nephrogenic cord from intermediate mesoderm (part of genital ridge)»_space; Mesonephric and paramesonephric ducts
Lower:
Cloaca from endoderm»_space; urogenital sinus
Describe the differentiation of male genital ducts from indifferent stage?
Mesonephric ducts transform
Paramesonephric ducts degenerate
Urogenital sinus»_space; distal urethra
Describe the differentiation of female genital ducts from indifferent stage?
Paramesonephric ducts transform
Mesonephric ducts degenerate
Urogenital sinus»_space; Uterovaginal primordium
Describe the structures derived from the differentiated stage of genital duct development in male?
Mesonephric duct derive into: • efferent ductules • duct of the epididymis • vas deferens • ejaculatory duct • Seminal glands
Distal urethra derive into :
• Penile urethra
• Prostate
• Bulbourethral glands
Describe the structures derived from the differentiated stage of genital duct development in female?
Paramesonephric duct derives:
- Uterine tubes
- Uterus
- Upper Vagina
Uterovaginal primordium derives:
- Greater vestibular glands
- Lower Vagina with hymen
Summarize the formation of external genitalia in male?
Genital tubercule»_space; Primordial phallus (long)»_space; Glans penis and shaft of penis
Urogenital folds fuse on ventral penis»_space; penile urethra
Labioscrotal swellings fuse»_space; scrotum
Summarize the formation of external genitalia in female?
Genital tubercule»_space; Primordial phallus (short)»_space; Clitoris
Urogenital folds don’t fuse»_space; Vestibule and labia minora
Labioscrotal swelling»_space; labial folds»_space; Labia majora
Describe the changes to the gonadal ridge and migration of primordial germ cells?
Gondal ridge= bulge medial to mesonephros at post. abdominal wall:
Epithelial lining invaginate into mesenchyme, forms gonadal cords
Primordial germ cells: Migrate from exit of allantois»_space; gut tube»_space; dorsal mesentery of hindgut»_space; gonadal ridge»_space; infiltrate gonadal cords
List the primordial cells in the indifferent gonad?
Mesothelium, gonadal cords, mesenchyme = mesoderm origin
Primordial germ cells = endoderm origin
Describe the formation of testis from indifferent gonad? (5)
1) Gonadal cords infiltrated with primordial germ cells»_space; elongate/ enlarge into seminiferous cords
2) Distal gonadal cord (no germ cell) forms straight tubules
» Rete testis: connect seminiferous cords with efferent ductules/mesonephric tubules»_space; connect with Mesonephric duct (Wolffian duct)
3) Mesenchymal cells»_space; Myoepithelial cells, Leydig, interstitial cells
4) Epithelial cells of gonadal cord = Sertoli cells
5) Mesothelium»_space; tunica vaginalis, Tunica albuginea, Septa
Describe the formation of ovary from indifferent gonad? (5)
1) Gonadal cords infiltrated with primordial germ cells form follicles: oogonium + follicular cells (from gonadal cord epithelium)
2) Distal gonadal cords degenrate into Rete ovarii, no connection with mesonephros
3) Epithelium of gonadal ridge»_space; tunica albuginea, germinal epithelium
Compare the differentiation of mesonephric duct and paramesonephric duct in male and female?
Male:
- Testosterone from leydig cells transforms mesonephric duct
- Anti-Mullerian hormone from Sertoli cells degenerates Paramesonephric ducts
Female:
- No testosterone = Mesonephric duct degeneration
- No anti-Mullerian hormone = paramesonephric duct transform
What structure separates cloaca into 2 canals?
Urorectal septum splits cloaca into
- Urogenital sinus (anterior)
- Rectum (posterior)
List the structures transformed from mesonephric duct in male?
Testosterone: convert mesonephric duct into -epididymis, -Ductus (vas) Deferens -seminal vesicle
List the structures transformed from paramesonephric duct in female?
Lack of Anti-Mullerian hormone:
Paramesonephric duct form:
- Fallopian tube
- Uterus and Upper vagina (fused paramesonephric duct)
List the sex organ structures derived from urogenital sinus in male?
Prostate gland (development controlled by dihydrotestosterone (DHT))
Bulbourethral glands
Penile urethra
List the sex organ structures derived from urogenital sinus in female?
Urethral and paraurethral glands
Greater vestibular glands (of Bartholin)
Lower vagina + hymen
Describe the development of uterus and vagina?
1) Paramesonephric ducts fuse + Uterine septum degenerate»_space; uterine tube
2) Sinus tubercule (from urogenital sinus) enlarge into sinovaginal bulbs»_space; fuse with uterine tube
3) Sinovaginal bulbs lumen degenerate»_space; become patent with space»_space; forms middle and lower vagina + hymen
List 3 developmental anomalies of uterus?
- Double uterus: failure of paramesonephric ducts to fuse
- Uterus divided into 2: failure of uterine septum to degenerate
- Dysmorphic/ absent half of uterus: failure on one paramesonephric duct to differentiate
Embryonic origin of phallus?
Genital tubercle:
Produced by proliferating mesenchyme at the cranial end of cloacal membrane
Describe the formation of precursors of external genitalia?
Superior to cloacal membrane = genital tubercule
Lateral to cloacal membrane = 2 urogenital folds
More lateral: 2 Labioscrotal swellings
Which week of development sees distinguishing sexual characteristics?
9th week
External genitalia are not fully differentiated until the 12th week.
Describe the formation of external male genitalia?
1) Genital tubercule rapidly elongates into primordial phallus»_space; glans and shaft of penis
2) Urogenital folds pulled along with genital tubercule»_space; fuse at underside of penis (perineal raphe)
3) Labioscrotal swelling = forms exterior wall and scrotum
4) Surface ectoderm invaginates > ectodermal cord > fuse with spongy urethra + create Navicular fossa and prepuce
Embryonic defect causing hypospadia?
ectopic location of the urethral meatus
Incomplete fusion of the urethral groove:
- incomplete development of the prepuce
- ventral skin deficiency/penile curvature
Describe the formation of external genitalia in female?
1) Genital tubercule curves ventrally > clitoris
2) Urogenital folds do not fuse > labia minora
3) Labioscrotal fold do not fuse»_space; Labia majora
Describe the relocation of the testis during development?
End of 2nd month:
- Gonads and mesonephros anchored to posterior abdominal wall
- Gubernaculum (fibromuscular cord) connect gonads to labioscrotal swelling
- Upper inguinal canal degenerates
- Testis dragged down/ out of abdominal cavity into scrotum below inguinal canal, behind Vaginal process
7 month:
- Upper vaginal process fuse, close off scrotum from Abd. cavity
Embryonic defect in ectopic testis or Cryptochidism?
Cyptochidism = retention of testis in abdominal cavity
Failure of correct migration into scrotum
Embyronic defect causing Hydrocele formation in testes?
Hydrocele = fluid secreting cyst between parietal and visceral layer of tunica vaginalis
Failure of vaginal process to fuse properly»_space; congenital indirect inguinal herniation (intestine loop pushed into scrotum)
Describe the relocation of the ovaries during development?
7th week:
- Gubernaculum attached to ovary, no shortening due to lack of Testosterone
- Gubernaculum persists as ligament:
i) cranial part - round ligament of OVARY, connect ovary to uterus
ii) Caudal part - round ligament of UTERUS, connect uterus to labia majora
