One Word_Embryology Flashcards
Wnt-7 gene
Produced at apical ectodermal ridge (thickened ectoderm at distal end of each developinf limb). Necessary for proper organization along dorsal-ventral axis.
Treacher Collins syndrome
1st-arch neural crest fails to migrate → mandibular hypoplasia, facial abnormalities
Teratogens: X-rays, anticonvulsants
Multiple anomalies
Teratogens: Warfarin
Bone deformaties, fetal hemorrhage, abortion
Teratogens: Vitamin A (excess)
Extremely high risk for spontaneous abortions and birth defects (cleft palate, cardiac abnormalities)
Teratogens: Valproate
Inhibition of intestinal folate absorption → Neural tube defects
Teratogens: Thalidomide
Limb defects (“flipper” limbs)
Teratogens: Tetracyclines
Discolored teeth
Teratogens: Smoking (nicotine, CO)
Preterm labor, placental problems, IUGR, ADHD
Teratogens: Maternal diabetes
Caudal regression syndrome (anal atresia to sirenomelia)
Teratogens: Lithium
Ebstein’s anomaly (atrialized right ventricle)
Teratogens: Iodide (lack or excess)
Congenital goiter or hypothyroidism
Teratogens: Folate antagonists
Neurol tube defects
Teratogens: Diethylstilbestrol (DES)
Vaginal clear cell adenocarcinoma
Teratogens: Cocaine
Abnormal fetal development and fetal addiction; placental abruption
Teratogens: Aminoglycosides
CN VIII toxicity
Teratogens: Alkylating agents
Absence of digits, multiple anomalies
Teratogens: Alcohol
Leading cause of birth defects and mental retardation; fetal alcohol syndrome
Teratogens: ACE inhibitors
Renal damage
Sonic hedgehog gene
Produced at base of limbs in zone of polarizing activity. Involved in patterning along anterior-posterior axis.
Homeobox gene
Involved in segmental organization or embryo in a craniocaudal direction
FGF gene
Produced at apical ectodermal ridge. Stimulates mitosis of underlying mesoderm, providing for lengthening of limbs.
Embryology: What is associated with Epispadias?
Exstrophy of the bladder
Embryology: Vitelline duct
7th week, obliteration of vitelline duct (omphalomesenteric duct), which connects yolk sac to midgut lumen.
Embryology: Uteropelvic junction with kidneys
last to canalize → most common site of obstruction (hydronephrosis) in fetus
Embryology: Urachal duct
3rd week, yolk sac forms allantois, later becomes urachus, a duct between bladder and yolk sac.
Embryology: Truncus arteriosus pathology
Failure neural crest migration: ①Transposition of great vessels (failure to spiral); ②Tetralogy of Fallot (skewed AP septum development); ③Persistent TA (partial AP septum development)
Embryology: Truncus arteriosus
Ascending aorta and pulmonary trunk
Embryology: Syncotiotrophoblast
outer layer of chorionic villi; secretes hCG (structurally similar to LH; stimulates corpus luteum to secrete progesterone during first trimester)
Embryology: Patent foramen ovale
Abnormal interatrial septum development caused by excessive resorption of septum primum and/or secundum
Embryology: Omphalocele
persistence of herniation of abdominal contents into umbilical cord, covered by peritoneum
Embryology: Jejunal, ileal, colonic atresia
Due to vascular accident (apple peel atresia)
Embryology: Hypospadias
abnormal opening of the penile urethra on inferior (ventral) side of penis due to failure of urethral folds to close
Embryology: Holoprosencephaly
↓seperation of hemispheres across midline; results in cyclopia; associated with Patau’s syndrome, severe fetal alcohol syndrome, and cleft lip/palate.
Embryology: Gastroschisis
extrusion of abdominal contents through abdominal folds; not covered by peritoneum
Embryology: Epispadias
abnormal opening of penile urethra on superior (dorsal) side of penis due to faulty positioning of genital tubercle
Embryology: Duodenal atresia
Failure to recanalize (trisomy 21)
Embryology: Decidua basalis
Maternal component, derived from the endometrium. Maternal blood in lacunae.
Embryology: Dandy-Walker syndrome
large posterior fossa; absent cerebellar vermis with cystic enlargement of 4th ventricle. Can lead to hydrocephalus and spina bifida.
Embryology: Cytotrophoblast
inner layer of chorionic villi. Cyto makes cells.
Embryology: Cricothyroid
Only larynx muscle innervated by the superior laryngeal branch
Embryology: Bulbus cordis
Right ventricle and smooth parts (outflow tract) of left and right ventricle
Embryology: Arnold chiari II
cerebellar tonsillar herniation through foramen magnum with aqueductal stenosis and hydrocephaly. Often presents with syringomyelia, thoraco-lumbar myelomeningocele.
Embryology: Anencephaly
Malformation of anterior end of neural tube; no brain/calvarium, elevated AFP, polyhydramnios (no swallowing center in brain).
Descent of testes and ovaries: Processus vaginalis (evagination of peritoneum)
Female remnant: Obliterated Male remnant: Forms tunica vaginalis
Descent of testes and ovaries: Gubernaculum (band of fibrous tissue)
Female remnant: Ovarian ligament + round ligament of uterus Male remnant: Anchors testes within scrotum
Congenital pharyngocutaneous fistula
persistence of cleft and pouch → fistula between tonsillar area, cleft in lateral neck
Branchial cleft derivatives
1st cleft - external auditory meatus 2nd - 4th clefts - form temporary cervical sinuses, which are obliterated by proliferation of 2nd arch mesenchyme Persistent cervical sinus → branchial cleft cyst within lateral neck
Basal plate
Ventral, motor
Aortic arch derivatives
1st-part of Maxillary artery (branch of external carotid) 2nd-Stapedial artery and hyoid artery 3rd-common Carotid artery and proximal part of internal carotid artery 4th-on left, aortic arch; on right, proximal part of right subclavian artery 6th-proximal part of pulmonary arteries and (on left only) ductus arteriosus
Alar plate
Dorsal, sensory
