Teratology Flashcards
fewer than ____ of human zygotes and less than ___ of all pregnancies result in normal, healthy babies
20-30%, half
one of every ___ infants die due to birth defects
5
as the embryo develops it ____ embryonic cellular potency and ____ cellular differentiation
loses, gains
major malformations usually occur during ____
organogenesis (critical period)
embryonic regulation:
internal rearrangements of development schedules, populations of cells which allows the fetus to respond to challenges
most birth defects are caused by:
unknown etiology
developmental plasticity
ability of a single gene to express more than one phenotype based on environmental conditions i.e. alligator eggs
aneuploidy
chromosome number is not a multiple of 23
aneuploidy is typically caused by:
nondisjunction during gametogenesis
Trisomy 18 is known as:
Edward syndrome
Trisomy 13 is known as:
Patau syndrome
Turner syndrome
45 X
Klinefelter syndrome
47 XXY
Cri du chat syndrome
deletion of short arm of chromosome 5
most common structural defect of X chromosome:
isochromosomes, centromere divides transversely instead of longitudinally
holoprosencephaly
SHH, failure of forebrain to completely separate into two lobes, wide range of brain, skull, and facial defects
achondroplasia
FGFR3, dwarfism
fetal hydantoin syndrome
embryo lacks epoxide hydrolase, can’t metabolize phenytoin
progressive maternal physiological changes during gestation
- plasma volume increases by 50%
- CO rises 30-50%
- GFR rises 50%
- decreased systemic vascular resistance
- decreased plasma protein binding
- altered electrolyte and mineral metabolism
- enhanced pulmonary ventilation
preeclampsia
blood vessels in uterus constrict, restricts blood supply to placenta and increases blood pressure in the mother
preeclampsia is associated with decreased levels of ___
VEGF
maternal diabetes is associated with:
- macrosomia
- spina bifida
- heart defects
- skeletal defects
- urinary, reproductive, and digestive tract defects
hyperthermia is associated with:
neural tube defects
malformations vs. deformations
deformations occur later in pregnancy, caused by a physical change
amniotic bands
fibrous bands from amnion-tears that attach to/encircle body parts
prader-willi syndrome
15q deletion in paternally-derived chromosome, associated with paternal hydrocarbon exposure
rubella virus/german measles classic triad of clinical signs
cataracts, hearing defects, patent ductus arteriosus
the most common viral infection at birth in US:
cytomegalovirus
toxoplasma gondii
in feces (litter box)
syphilis side effects
stillbirth dental anomalies deafness mental retardation skin/bone lesions meningitis
phenocopy
a phenotype can be caused by multiple factors
the leading known preventable cause of mental retardation and birth defects is:
alcohol
the most sensitive period for fetal alcohol syndrome is:
the first month of gestation
how does smoking probably affect infant mortality?
by leading to more preterm births
what halogenated aromatic hydrocarbons were most likely the bad actor, causing birth defects?
PCDF
what causes ouch-ouch disease?
mercury exposure
