High Yield Embryology Flashcards
Teratogen
Substance affecting migration, proliferation, or interaction of cells
Causes congenital anomalies
Capacitation
Pruning of the sperm glycocalyx; permits the sperm-oocyte interaction
Ectopic pregnancy
Implantation that occurs outside of the uterine cavity; can occur in uterine tubes or in the pelvic cavity
Placenta Previa
Implantation occurs near the cervix
Provides high risk of bleeding
Placental Abruption
Placenta becomes attached
Placenta accreta
Abnormal adherence of the chorionic villi to the myometrium
Placenta percreta
Villi penetrate the full thickness of the myometrium
Hydatidiform moles
Result when there is no embryo or embryo dies and chorionic villi fail to vascularize
“Uterine enlargements greater than expected for gestational age”
What are long-term complications of hydatidiform moles?
Give rise to choriocarcinomas or persistent trophoblastic disease
Complete mole
Fertilization of empty oocyte (contains only paternal chromosomes)
Produces high levels of hCG
Partial moles
Derive from a poorly developed embryo
Always triploid and produce hCG
Dizygotic (fraternal) twins
Arises from multiple ovulations (high levels of FSH)
Monozygotic (identical) twins
Arise from splitting of single zygote
Human chorionic gonadotrophin (hCG)
Secreted by syncytiotrophoblast
Progesterone
Secreted by corpus luteum for five months, then by placenta
Contraceptive “pill” and RU-486 are anti-progesterones
Gastrulation
Process where the epiblast gives rise to mesoderm, endoderm, and ectoderm
Notochord
Derives from both endoderm and mesoderm; forms the nucleus pulposus
Sirenomelia
Caudal dysgensis from inadequate mesoderm
Lower limb defects
Sacrococcygeal teratoma
Persistence of primitive streak, forms multi-tissue tumor
Alpha-fetoprotein
Liver glycoprotein
Leaks into amniotic fluid with neural tube or ventral wall defects
Spina bifida occulta
Incomplete neural arch, patch of hair over defect
Poland anomaly
Congenital absence of the pectoralis major
Congenital torticollis
Contracture/shortening of the sternocleidomastoid
Amelia
absence of a limb
Meromelia
Absence of part of a limb
Congenital clubfoot
Any defect involving the talus
What does splanchnic mesoderm form?
Primitive heart tube
Beats on day 22
Pleuropericardial membranes
Form pericardium and pleura (somatic parts)
Tetrology of Fallot
A combo of 4 heart defects
- pulmonary stenosis
- right ventricular hypertrophy
- over-riding aorta
- ventricular septal defect
Dextrocardia
Right-sided heart
Undivided truncus arteriosus
Neural crest defect where the bulbar regions fail to form
Patent ductus arteriosus
Common defect associated with rubella and pregnancies occurring in high altitudes, more common in females
Atrial septal defect
Patent foramen ovale common
Can involve defect in septum primum or septum secundum
Ventricular septal defect
Common
Involves membranous part of the interventricular septum
Transposition of the great vessels
Most common cause of cyanosis in newborn
Vitelline vein
Left disappears, right forms portal system
Umbilical vein
Right disappears
Left drains placenta - becomes ligamentum teres hepatis
Cardinal vein
Subcardinal - drains kidneys
Sacrocardinal - common iliac
Supracardinal - drains body wall (azygos veins)
Ductus venosus
Between left umbilical and right vitelline veins
Forms ligamentum venosum
Early development of lung
Begins in 4th week, derived from gut tube
Lungs become viable during the 24th gestational week due to secretion of surfactant
When does formation of most alveoli occur?
Between birth and the 8th year
Tracheoesophageal fistula
Abnormal connection between esophagus and airway
Usually involves a proximal esophagus that ends in a blind pouch and a distal esophagus that connects to the trachea
VACTERL association
Combination of defects that arise from exposure to high levels of estrogens/progesterones during the embryonic period (weeks 3-9) Vertebral defects Anal atresia Cardiac defects Trachioesophageal fistula Renal anomalies Limb abnormalities
