Fetal Congenital Anomalies Flashcards
Describe early embryogenesis.
zygote –> morula –> blastocyst –> embryo and trophoblast
blastocyst implants into endometrium (wk 1)
trophoblast differentiates into inner cytotrophoblast and outer syncytiotrophoblast (together eventually give rise to placenta)
inner cell mass divides into epiblast and hypoblast (bilateral germ disc)
gastrulation (wk 3) –> primitive streak, epiblast invagination into 3 germ layers (endoderm, mesoderm, ectoderm)
Endoderm gives rise to
GI and Respiratory system
Mesoderm gives rise to
Cardiovascular, MSK, GU
Ectoderm gives rise to
Nervous system, skin, sensory organs (hair, eyes, nose, ears)
Organogenesis lasts from:
5-10 wks GA
When does the neural tube form?
When do anterior and posterior neuropores close? Significance?
wk 4 (= days 22-23)
anterior closes day 25, posterior closes day 27. Majority of NTDs develop as result of defective closure by 6 wks GA
What is the classic finding of spina bifida on US?
“Lemon sign” (concave frontal bones) and
“Banana sign” (flattened cerebellum pulled caudally)
When does cardiac development begin?
When does the heart tube become a cardiac loop?
wk 3
between day 23-28
What will bulbus cordis form?
trabeculated part of RV
outflow tracts of ventricles
proximal aorta and pulm artery
Septum formation is achieved via formation of what?
Endocardial cushions
Cause of Potter Syndrome?
Renal Failure –> anhydramnios –> pulm hypoplasia, contractures of limbs
When does kidney development begin?
Wk 4
Mesonephros forms what?
Mesonephric Wolffian duct
What forms the urinary collecting system (collecting tubules, calyces, renal pelvis, ureter)?
Wolffian duct –> ureteric bud –> urinary collecting system
In the presence of testosterone, Wolffian duct also forms what?
vas deferens, epididymis, ejaculatory duct, and seminal vesicles
