6.2 Embryonic development of EXTERNAL GENITALIA and GENITAL DUCT DERIVATIVES Flashcards
MESONEPHRIC DUCTS aka
WOLFIAN DUCTS
PARAMESONEPHRIC DUCTS aka
MULLARIAN DUCTS
when does DEVELOPMENT of EXTERNAL GENITALIA start
around 4 WEEKS
DEVELOPMENT OF EXTERNAL GENITALIA landmark weeks
week 4
(week 7)
week 9
week 12
DEVELOPMENT OF EXTERNAL GENITALIA
what happens at WEEK 4:
proliferating MESENCHYME produces a GENITAL TUBERCLE - primordium of CLITORIS or PENIS
at CAUDIAL (TAIL) end
DEVELOPMENT OF EXTERNAL GENITALIA
what do we have at week 7
External Genitalia are SEXUALLY UNDIFFERENTIATED
- only takes place when testosterone produced (8 weeks)
DEVELOPMENT OF EXTERNAL GENITALIA
what begin to appear at WEEK 9
DISTINGUISHING SEXUAL CHARACTERISTICS
DEVELOPMENT OF EXTERNAL GENITALIA
what do we have at WEEK 12 and what happens
FULLY DIFFERENTIATED external genitalia
which GROWTH FACTOR is found to be involved in the SINGALLING PATHWAYS in the EARLY DEVELOPMENT of EXTERNAL GENITALIA (WEEK 12)
FGF8
(testosterone is not the only factor involved)
DEVELOPMENT OF EXTERNAL GENITALIA
what develop on EACH SIDE of the CLOACAL MEMBRANE
LABIOSCROTAL SWELLINGS and UROGENITAL FOLDS
DEVELOPMENT OF EXTERNAL GENITALIA
GENITAL TUBERCLE soon ELONGATES to form a …
PRIMORDIAL PHALLUS
- PENIS / CLITORIS
DEVELOPMENT OF EXTERNAL GENITALIA
in a FEMALE fetus the URETHRA and VAGINA OPEN into a COMMON CAVITY called ..
the VESTIBULE of the VAGINA
what is MASCULINIZATION INDUCED by
DHT
DIHYDROTESTOSTERONE
what is DHT (DEHYDROTESTOSTERONE) PRODUCED peripherally by..
5 ALPHA-REDUCTASE CONVERSION of TESTOSTERONE (produced by Leydig cells)
TESTOSTERONE is converted to DHT by which ENZYME in order for it to work
5 ALPHA REDUCTASE
in MALES
the EPITHELIUM of the URETHRA comes from the..
ENDODERM of the UROGENITAL SINUS (comes from cloaca)
(except for that of the distal part of the spongy urethra in males)
GLANULAR part of the URETHRA (urethra of the GLANS) is derived from..
ECTODERM
the GENITAL TUBERCLE, CONNECTIVE TISSUE and SMOOTH MUSCLE are derived from..
SPLANCHNIC MESENCHYME
the Embryo has 2 PAIRS of GENITAL DUCTS:
MESONEPHRIC DUCTS (WOLFFIAN) - persist in males
PARAMESONEPHRIC DUCTS (MULLERIAN) - persist in females
example of a vestigial structure that remains after DUCTS regress
remnant of paramesonephric duct:
APPENDIX TESTIS in the MALE
what happens to the MESONEPHRIC DUCTS in FEMALE embryos and why
REGRESS
in ABSENCE of TESTOSTERONE
what happens to the PARAMESONEPHRIC DUCTS in FEMALE embryos and why
DEVELOP
due to ABSENCE of AMH (ANTIMULLERIAN HORMONE)
(form most of the female genital tract)
female sexual development does not depend on the presence of ovaries or hormones until..
puberty
what do both MESONEPHRIC DUCTS and PARAMESONEPHRIC DUCTS connect to
UROGENITAL SINUS (developed from cloacal membrane)
FEMALES:
CRANIAL PARTS of the PARAMESONEPHRIC DUCTS remain UNFUSED and become the..
UTERINE TUBES (fallopian tubes)
FEMALES:
CAUDAL PARTS of the PARAMESONEPHRIC DUCTS FUSE to form the..
UTEROVAGINAL PRIMORDIUM
- uterus, upper 3rd of vagina and broad ligament
FEMALES:
which end of the PARAMESONEPHRIC DUCTS FUSE and what does it form
CAUDAL
- UTEROVAGINAL PRIMORDIUM
FEMALES
what will the UTEROVAGINAL PRIMORDIUM become
Uterus, Upper 3rd of VAGINA, BROAD LIGAMENT
FEMALES
important GENE for regulating PARANEPHRIC DUCTS
HOX genes
FEMALES
the ENDOMETRIAL STROMA and MYOMETRIUM (connective tissue and muscle) are derived from..
SPLANCHNIC MESENCHYME
EPITHELIUM of the VAGINA develops from the..
ENDODERM of the UROGENITAL SINUS
FIBROMUSCULAR WALL of VAGINA develops from the..
UTEROVAGINAL PRIMORDIUM
DEVELOPMENT OF VAGINA
when UTEROVAGINAL PRIMORDIUM meets the UROGENITAL SINUS this area is called the..
SINUS TUBERCLE
DEVELOPMENT OF VAGINA
formation of SINUS TUBERCLE INDUCES the formation of..
SINOVAGINAL BULBS
paired endodermal outgrowths
which extend from the UROGENITAL SINUS to the CAUDAL END of the UTEROVAGINAL PRIMORDIUM
DEVELOPMENT OF VAGINA
SINOVAGINAL BULBS FUSE to form a..
VAGINAL PLATE
DEVELOPMENT OF VAGINA
how does the VAGINAL PLATE form the LUMEN of the VAGINA
CENTRAL WALLS of vaginal plate BREAK DOWN
DEVELOPMENT OF VAGINA
the PERIPHERAL CELLS of the VAGINAL PLATE form the
VAGINAL EPITHELIUM
DEVELOPMENT OF VAGINA
later in foetal life the LUMEN of the VAGINA is SEPARATED from the cavity of the UROGENITAL SINUS by a MEMBRANE:
and how is it formed
HYMEN
- formed by INVAGINATION of the POSTERIOR WALL of the UROGENTIAL SINUS
(ruptures during Perinatal period - first 28 days after birth - and remains as a thin mucous membrane just within the vaginal orifice)
DEVELOPMENT OF VAGINA
later in foetal life the LUMEN of the VAGINA is SEPARATED from the cavity of the UROGENITAL SINUS by a MEMBRANE:
and how is it formed
HYMEN
- formed by INVAGINATION of the POSTERIOR WALL of the UROGENTIAL SINUS
(ruptures during Perinatal period - first 28 days after birth - and remains as a thin mucous membrane just within the vaginal orifice)
DEVELOPMENT OF MALE DUCTS
when do TESTES start to produce TESTOSTERONE
WEEK 8-12
DEVELOPMENT OF MALE DUCTS
when do TESTES start to form AMH
(paramesonephric ducts disappear by epithelial-mesenchymal transformation)
WEEK 6-7
DEVELOPMENT OF MALE DUCTS
as MESONEPHROS (kidney development) DEGENERATES, some tubules PERSIST as..
EFFERENT DUCTULES
opening into the MESONEPHRIC DUCT
DEVELOPMENT OF MALE DUCTS
MESONEPHRIC DUCTS become
DUCT of EPIDIDYMIS
or
distal to epididymis, acquires a thick investment of SMOOTH MUSCLE and becomes the
DUCTUS DEFERENS
or
EJACULATORY DUCT
(from mesonephric duct between the duct of seminal vesicle and the urethra)
DEVELOPMENT OF MALE DUCTS
LATERAL OUTGROWTHS of the CAUDAL END of the MESONEPHRIC DUCT become..
SEMINAL VESICLES
MALES
SECRETIONS of SEMINAL VESICLES contribute how much of the volume of EJACULATE
50-80%
MALES
multiple ENDODERMAL OUTGROWTHS arise from the Prostatic part of the URETHRA and GROW INTO the SURROUNDING MESENCHYME to FORM..
PROSTATE GLAND
what do the EFFERENT DUCTS of testes come from
MESONEPHRIC TUBULES
What does RETE TESTES come from
Sex Cords
what do the CLITORIS and PENIS originate from
GENITAL TUBERCLE
(elongates into primordial phallus)