Chapter 1: Embryology Flashcards
The urogenital system develops from _ .
intermediate mesoderm
The adrenal gland starts forming during the _#_ week.
6th
Adrenal cortex is from _ .
mesoderm
For the adrenal gland, the zona _ and zona _ are present at birth.
glomerulosa fasciculata
For the adrenal gland, the zona _ is not established until 3 years of age.
reticularis Think of it as you don’t need sex hormones until your’re older.
The adrenal medulla is from _ .
neural crest cells (sympathetic ganglion)
The adrenal gland is located [within or outside of] Gerota’s fascia.
within
Because the adrenal gland is from a totally different embryologic origin than the kidney, renal _ or _ does NOT affect adrenal development and location.
agenesis malposition
Pronephros develops during the _#_ week.
4th
Transient and nonfunctional A. Pronephros B. Mesonephros C. Metanephros
Pronephros
The pronephros develops _ toward the cloaca.
caudally
The pronephros disappears leaving behind the _ .
pronephric duct
The mesonephros is present during weeks _#_ - _#_ during development.
4-8
The mesonephros has _ function.
interim
The mesonephros joins the pronephric duct to yield the _ which opens into the cloaca.
mesonephric duct (Wolffian duct)
The _ (aka METAnephric diverticulum) forms during week 5 via diverticulum off the mesonephric duct.
ureteric bud
There is an association between the clinical findings of an absent vas deferent and ipsilateral _ . The common problem is the _ .
renal agenesis mesonephric (Wolffian) duct
_ develop lateral to the mesonephric duct and gonads. They are critical for female reproductive organs.
Paramesonephric ducts
The metanephros is functional at week _#_.
9
Gonadal ridge →[_, _]→ Indifferent gonad
WT-1 SF-1
Indifferent gonad →[_, _]→ Testicle
SOX-9 SRY
Indifferent gonad →[_, _]→ Ovary
DAX-1 Wnt-9
The ureteric bud moves cranially and penetrates the _ .
metanephrogenic blastema
Ureteric bud gives rise to _, _, _, _.
ureter renal pelvis calices collecting tubules
Metanephrogenic blastema gives rise to the _ .
nephron (glomerulus, proximal tubule, loop of Henle, and distal tubule)
As the ureteric bud is branching near the cloaca, caudally it is absorbed into the _ .
genitourinary sinus (i.e. bladder)
The pelvic forming kidney ascends to the _ position and rotates in an orientation similar to that of the psoas muscle.
L1/T12
The _ is a common cavity with merging of genitourinary and intestinal systems.
Cloaca
The cloaca is distal _.
hind gut (endoderm)
By the week _#_, the cloaca is divided by the _ creating an anterior _ and posterior rectum.
7 urorectum septum urogenital sinus
The urogenital sinus start week _#_.
8
The urogenital sinus is divided into upper (_), pelvic (_,_) and phallic (_,_)
bladder prostatic urethra and entire female urethra genital tubercle, distal male urethra
The _ is the location where the Wolffian ducts fuse to the urogenital sinus.
verumontanum
Bladder development happens at week _#_-_#_
9-12
Trigone, ureteric orifice and ejaculatory ducts are derived from _ while the rest of the bladder is _.
mesoderm (mesonephros) endoderm (urogenital sinus)
The entire floor of the urethra in females is made of _.
mesoderm
Allantois becomes the _ around week 12, which becomes the _ in the adult.
urachus median umbilical ligament
_ of the urachus is seen at the dome of the bladder and is one of the few indications for partial cystectomy.
Adenocarcinoma
In females the _ regresses in response to a lack of testosterone and the _ persists to form the uterus, Fallopian tubes, and superior 1/3 of the vagina
mesonephric (Wolffian) duct paramesonephric (Mullerian) duct
During week 5, medial to the bilateral mesonephros, a gonadal ridge is formed from germinal epithelial cells and mesenchyme under the genetic influence of _ and _.
Wilms tumor (WT1) Steroidogenic factor-1 (SF-1)
Primordial germ cells migrate into the mesenchyme forming _, thus the indifferent gonad is developed.
primary sex cords
The indifferent gonad has a cortex (which forms the _) and a medulla (which forms the _).
ovary testicle Medulla in Med Think O in cortex is for O-vary
Indifferent gonad becomes testicle under influence of _ and _.
SOX-9 (SRY-relaed HMG box) SRY (sex determining region Y)
Ovary is influenced by _ and _.
Wnt-4 (wingless-related MMTV integration site 4) DAX-1 (dosage sensitive sex-reversal adrenal hypoplasia congenital-critical region of the X chromosome, gene !)
Teste formation starts week _#_.
7
The SRY gene is located on _ which is required for testosterone production and testicular development.
Yp11.3 short arm of the Y chromosome
Primary sex cords of the indifferent gonad condense into the gonadal medulla to form the _ and _.
rete testis seminiferous cords
The _ encases the seminiferous cords to form the testicle.
tunica albuginea
Seminiferous cords become_, _, _.
seminiferous tubules tubular recti rete testes
Seminiferous tubules lack a _ until puberty.
lumen
_ develop between seminiferous tubules. They secrete testosterone and androstenedione by week 8.
Interstitial cells of Leydig Lydia cells secrete testosterone Sertoli cells do everything else
Sertoli cells line the seminiferous tubules and secrete _ caused the paramesonephric (Mullerian) ducts to regress.
Mullerian inhibiting substance
Then the mesonephric (Wolffian) ducts migrate caudally to form the _, _, _, _, _ under the influence of testosterone.
SEEED seminal vesicles ejaculatory ducts epididymis efferent ductules ductus deferens
_ testosterone is necessary for Wolffian duct development.
Local
During week 9, _ appear as outpouchings from the epididymis connect to the _ to establish the first genitourinary connection.
efferent ductules rete testis
The testicular attachment to the mesonephros becomes _, and by month 8, the testicle descends into the scrotum with guidance from the _.
mesorchium gubernaculum
On the way down through the inguinal canal, the testicle takes some peritoneum, aka _, into the scrotum forming the _.
processus vaginallis tunica vaginalis
If the process vaginalis is patent, peritoneal fluid may flow into the surrounding area and cause a _ or _.
communicating hydrocele congenital inguinal hernia The majority of hydroceles in infancy will resolve spontaneously.
Ovary starts week _#_.
8
If testicles do not develop, a definitive _ will.
ovary #defaultdevelopment
At 4 months, the cortical cords from the female gonadal surface epithelium (cortex) divide into isolated cell clusters known as _.
primordial follicles (oogonia and follicular cells)
The _ undergo mitosis to produce primodular follicles and ultimately primary oocytes.
oogonia All oogonia are formed while a fetus.
Females are born with ~_#_ primary oocytes arrested in Prophase 1 of meiosis until menarche.
2 million At puberty, FSH stimulates a few primary oocytes to re-enter meiosis until one dominant follicle enters ovulation, normally on a monthly basis
At week 4, a _ is formed on the cloacal membrane with _ and _ developing bilaterally to the tubercle.
genital tubercle labioscrotal swellings urogenital folds
The genital tubercle elongates to form the _.
primordial phallus
Genital tubercle → primordial phallus → _ or _.
glans penis clitoris
Penis forms week _#_-_#_.
9-12
Masculinization of the primordial phallus via _.
DHT (dihydrotestosterone)
The urogenital folds near surround the _ except at the future site of the penile raphe, which creates a _.
urethral plate (endoderm) urethral groove
The urogenital folds fuse completely resulting in the invagination and tubularization of the urethral place/groove to form the _.
spongy urethra The urogenital fold is covered by ectoderm (penile skin) and fuses to form the penile raphe as the urogenital folds fuse.
Penile _ forms the corpus cavernosum/spongiosum.
mesenchyme
During week 11, at the glans penis, an _ forms to travel proximally and join the spongy urethra forming the fossa naviculars/urethral meatus.
ectodermal cord (invagination of ectoderm/penile skin) If the spongy urethra does not meet with the ectodermal cord, a hypospadias will develop.
During week 12, the ectoderm also has a circular ingrowth around the glans to form the _.
prepuce
The _ fuse in the medicine to form the scotum.
labioscrotal swellings If a hemiscrotum is hypoplastic, an undescended testicle is likely present.
Feminization of the primordial phallus via _ form the clitoris.
estrogens
_ only fold posteriorly resulting in the unfused portions becoming the labia majora.
Urogenital folds
_ fused posteriorly and anteriorly (labial commissures and mons pubis) resulting in the unfused portions becoming the labia majora.
Labioscrotal folds Urogenital folds only fold posteriorly.
_ produces the pre-ejaculate that neutralizes the pH of the urethra and lubricates it for seminal ejaculation.
Cowper’s glands Located at the membranous urethra with ducts entering the urethral bulb.
_ produce vaginal lubrication.
Bartholin’s glands Located at 5 and 7 o’clock positions.
Prostate forms week _#_.
12
The prostate is formed from the pelvic portion of the _ under stimulation of DHT.
urogenital sinus
Female analogous structures of the prostate is the _ located within the vulva at 4 and 8 o’clock positions.
Skene’s glands
In the absence of MIS, the _ will further develop.
paramesonephric ducts
The paramesonephric ducts fuse caudally to form the _ while the cranial unfused portion become the uterine tubes.
ureterovaginal primordium (uterus and upper vagina) The fusion also creates the broad ligament.
The lower vagina is formed from the _, which joins the ureterovaginal prim odium to form the sinus tubercle and then a pair of _.
urogenital sinus sinovaginal bulbs
Fusion of the sinovaginal bulbs form the _.
vaginal plate The center cells forms the vaginal lumen while the peripheral cells form the vaginal mucosa.
The _ is an invagination of the urogenitial sinus posterior wall.
hymen
The _ passes through the inguinal canal to join the labia majora during ovarian descent into the pelvis.
round ligament This is similar to testes/gubernaculum descent. If there is persistent processes vaginalis, is is called the canal of Nuck.
The mesonephric (Wolffian) duct responds to _.
Testosterone
The urogenital sinus responds to _ when forming the prostate, penis, and scrotum.
DHT (dihydrotestosterone)
Testicular efferent ductules
Embrylogic structure?
Epididymis, vas deferens
Embryologic structure?
Female analog?
Mesonephric duct
Ureter, renal pelvis, calices, collecting tubes
Embryologic structure?
Mesonephric duct
Fallopian tubes
Embryologic structure?
Male analog?
Uterus and upper vagina
Embryologic structure?
Male analog?
Bladder, urethra
Embryologic structure?
Prostate
Embryologic structure?
Female analog?
Cowper’s glands
Embryologic structre?
Female analog?
Verumontanum
Embryologic structure?
Female analog?
Gubernaculum
Female analog?
Urogenital folds become what in the male and female?
Labioscrotal swellings become what in the male and female?
