Embryology Flashcards
What mesoderm goes on to form the urogenital system?
Intermediate mesoderm
In which region of the body does pronephros form?
Cervical region
In which region of the body does mesonephros form?
Thoracolumbar region
In which region of the body does metanephros form?
Pelvic region
What structure in the embryo acts as a common opening for the gut tube and urogenital system?
Cloaca
What does the cloaca divide to form?
Rectum
Urogenital sinus
What does the mesonephric duct drain into?
Urogenital sinus
What structure does the allantois extend from?
Cloaca
What does the allantois degenerate into?
Urachus (Median umbilical ligament)
What does the gonadal ridge form from?
A thickening of mesonephros
What forms the indifferent gonad?
Germ cells migrating from yolk sac, that embed into primitive sex cords (from genital ridges)
What forms the paramesonephric duct?
Epithelium envaginating from the mesonephric duct
Which duct (mesonephric / paramesonephric) degenerates in male gonad formation?
Paramesonephric (Mullerian) duct
Which duct (mesonephric / paramesonephric) degenerates in female gonad formation?
Mesonephric (Wolffian) duct
What structure forms the epididymis, vas deferencs and seminal vesicle in males?
Mesonephric duct
What structure forms the bladder, urethra and prostate in males?
Urogenital sinus
What structure forms the fallopian tube, uterus, cervix in females?
Paramesonephric duct
What structure forms the bladder and lower part of the vagina?
Urogenital sinus
What gene in males develops the indifferent gonad into a testes?
SRY gene
What protein does SRY encode for?
TDF (testis determining factor)
What do primordial supporting cells that express the SRY gene become?
Sertoli cells
What is secreted by Sertoli cells?
Mullerian-Inhibiting-Substance
What does MIS transform mesenchymal cells between cords to form?
Leydig cells
What does MIS do to the paramesonephric duct?
Degeneration
What hormone is produced by Leydig cells to form external genitalia?
Testosterone
What is the default state of differentiation for the indifferent gonad?
Development into ovary
What structure contracts to pull gonads into the pelvic region (and through the inguinal canal in males)?
Gubernaculum
What structure does the gubernaculum form in females?
Ovarian and round ligament
What are some complications of undescended testes?
Infertility
Malignant transformation
Testicular torsion
What may degenerated mesonephros lead to in females?
Cyst formation
List some anomalies of the female reproductive tract
Complete duplication
Bicornuate uterus
Septate uterus
Arcuate uterus
During which week of embryonic development does gastrulation, neurulation and somite formation occur?
Week 3
Which weeks of embryonic development are concerned with organogenesis?
Weeks 4-8
What happens if there is a failure of germ cell migration?
No gonads formed
In males, what does the seminal vesicles develop from?
Outgrowth from caudal end of mesonephric duct
In males, what does the prostate develop from?
Outgrowth from the urethra (from urogenital sinus)
In females, what does the caudal end of the paramesonephric duct become?
Uterus and superior part of vagina
At what stage do the testis enter the scrotum?
Just prior to birth
What is the management for undescended testes?
Orchiopexy
List some of the effects of teratogens?
Intrauterine death Structural (congenital) malformations IUGR or growth defects Neurodevelopmental/behaviour dysfunction Developmental delay Carcinogenesis
List some facial differences in fetal alcohol syndrome?
- Small head
- Low nasal bridge
- Epicanthal folds
- Smooth philtrum
- Thin upper lip
- Underdeveloped jaw
What is the classical triad for congenital rubella syndrome?
- Sensorineural deafness
- Eye abnormalities (esp. retinopathy, cataract and microphthalmia)
- Congenital heart disease (pulmonary artery stenosis and patent ductus arteriosus)
What medications may cause respiratory depression in neonates?
Opiate medications
When is the greatest risk of adverse effects on teratogen exposure?
Weeks 3 and 11
Where does the uterine artery pass in relation to the ureter?
Ureter passes under the uterine vessels
Where does the ureter pass in relation to the bifurcation of the iliac vessels?
Ureter passes over bifurcation of iliac vessels
What spinal nerves provides sympathetic supply to the ureter?
T10-T11
What spinal nerves provides parasympathetic supply to the ureter?
S2-4
What spinal nerves provides sensory supply to the ureter?
T11-T12
What are the three constrictions of the ureter?
- Pelvi-ureteric Junction
- Pelvic Brim
- Intramural part
What are some technical risk factors for ureteric injury in hysterectomy?
- High BMI
- Haemorrhage
- Coexistent bladder injury
- inexperienced surgeon