Embryology Flashcards
elevated AFP and acetylcholinesterase in amniotic fluid indicates? which can also be found in maternal serum?
neural tube defects-failed fusion of neurospores (at anterior or posterior ends) leads to communication between spinal canal and amniotic cavity. AFP
failure of fusion at caudal (posterior) end of neural tube? rostral (anterior) end?
spinal bifida occulta, meningocele, meningomyelocele
encephalocele (herniation of brain tissue through cranial defect) and anencephaly (total absence of brain and calvarium)
name some clinical features of hypothyroidism in children
lethargy, feeding problems, constipation, macroglossia, umbilical hernia, large fantanels, dry skin, hypothermia, and prolonged jaundice.
problems with differentiation of cells can lead to
leukemias
how formation of mature thyroid occur?
when thyroid follicles (from an evagination of the pharyngeal epithelium) and parafollicular C-cells (from the ultimobrachial bodies) fuse together
ultimobrachial body-embryological structure that gives rise to the calcitonin-producing cells—also called parafollicular cells or C cells—of the thyroid gland. In humans, this body is a derivative of the ventral recess of the fourth pharyngeal pouch
intracrainial calcified cystic mass filled with thick yellow-brownish fluid that is rich in cholesterol
craniopharyngiomas
the lecithin-sphingomyelin is a marker of?
fetal lung maturity
what hormone helps accelerate fetal lung maturation?
cortisol from fetal adrenal gland and cortisol from mother
what is role of hCG during preganncy? oxytocin? progesterone?
resembles LH, FSH, and TSH- functions to support the corpus lutem so that there is enough progesterone to maintain pregancy
- stimulates myometrial contraction- levels are stable throughout preg, receptor expression increases in myometrium before delivery
- preparing endometrium for implantatoin
name one of the most common causes of elevated AFP levels. decreased level?
underestimation of gestational age (confirm with ultrasound)
Downs syndrome
triple test mesaures. abnormal levels of each hormone indicate?
AFP, hCG, and estriol
AFP- underestimation of gestational age (increased); Downs (decreased)
estriol-placental insufficiency (decreased)
hCG- multiple gestation, hydatidiform mole, and choriocarcinoma (increased)
urachus vs allantosis vs yolk stalk
urachus is remnant of the allantois that connects the bladder to the yolk sack. the allantois connects the urogenital sinus to the yolk sac. upper part of urogenital sinus becomes the bladder.
-aka vitelline duct, aka omphalomesenteric duct-connects yolk sac to midgut lumen
patent urachus
vesicourachal diverticulium
urachal sinus
urachal cyst
connection between umbilicus and bladder- urine discharge from umbilicus
failure to close part of urachus close to bladder-outpouching of apex of bladder, asymptomatic
failure to close distal part of urachus close to umbilicus-periumbilical tenderness and purulent discharge b/c of reccurrent infections
failure of central portion of urachus to obiterate- fluid filled structure b/t obilterated ends of urachus, asymptomatic
persistent yolk stalk
Meckel diverticulum
aka vitelline fistula, connect small intestine to umbilicus. meconium discharge from umbilicus
-incomplete obliteration of vitelline duct at proximal end - outpouching of small intestine
omphalocele vs gastroschisis
incomplete closure of anterior abdominal wall-viscera protrude through umbilicus, covered by peritoneum
-inadequate enlargement of peritoneal cavity-viscera protrude next to umbilicus not covered by peritoneum
congenital abnormality seen with valproate in pregnant women. why?
neural tube defects. it inhibits intestinal folic aicd absorption
congenital abnormality associated with Turner’s syndrome and bicuspid valves
coarctation of aorta
congenital abnormality associated with Downs syndrome
duodenal atresia-bilious vomiting without abdominal distention
congenital abnormality associated with Potter’s syndrome
renal agenesis
failure of paramesonephric ducts to fuse leads to? normal fusion creates what 4 structures in females? what happens to p. duct in males?
fusion leads to uterine tubes, uterus, cevix, and superior 1/3 of vagina formation. failure results in bicornuate uterus (partial fusion) or uterus didelphys (no fusion 2 of everything).
-p. ducts involute in males leaving vestige appendices of testes
mesonephric duct forms what in females? in males?
gartner’s ducts
efferent ductules-carry sperm from testies to epididymis SEED (seminal vesicles, epididymis, ejactulatory duct, ductus deferens)
urethral folds fuse to form what in males? females?
urethra in both
improper fusion can lead to hypospadias in males