Teratogenesis Flashcards
teratogenesis stands for
developmental toxicology
abnormal development of fetus/embryo leading to birth defects
teratogenesis
agents that induce teratogenesis
teratogens
four different types of teratogenic stressors
radiation
infections
maternal conditions
xenobiotics
Wilson’s six principles of teratology
- susceptibility dependent on genotype and environmental factors
- susceptibility dependent on developmental stage during exposure
- teratogens have specific mechanisms that lead to pathogenesis
- the nature of the teratogen determines its access to the target
- the manifestations are death, malformation, growth retardation, or functional deficits
- effects are dose related
the zygote to gastrula are ____
not sensitive to teratogens
after what week can teratogens affect the developing embryo
after week two
part of development when organs start to develop
organogenesis
Part of development where the developing organism is the more sensitive to teratogens
organogenesis
What occurs during gametogenesis
imprinting or gene silencing
what occurs during pre-implantation
blastocyst formation
what occurs during post-implantation
gastrulation
organogenesis
four things that happen during organogenesis
cell proliferation
cell migration
cell-cell interaction
tissue remodeling via apoptosis
the process of forming the haploid germ cells or gametes
gametogenesis
biochemical changes in chromatin that lead to changes in conformation and gene expression
epigenetics
three things epigenetics includes
DNA methylation
histone modification
expression of microRNA
what are the three primary germ layers
ectoderm
mesoderm
endoderm
it is common for teratogens administered during gastrulation to produce malformation in the
eye, brain, and face
the end of organogenesis marks the beginning of
the fetal period
what are three characteristics of the fetal period
tissue differentiation
growth
physiological maturations
exposure of teratogens during the fetal period is most likely to result in effects on
growth and functional maturation
compromises the cell, tissue, and organ level sequelae that ultimately lead to abnormality
pathogenesis
8 mechanisms of developmental toxicology
mutations chromosomal damage altered mitosis diminished supply of substrates decreased energy supply altered membranes osmolar imbalance enzyme inhibition
three cellular pathogenic effects
proliferation
differentiation
apoptosis
physiological changes in mother during pregnancy
hepatic function: changes in enzymes
GI tract changes: changes in absorption
Cardiovascular: changes in blood flow
excretory and respiratory functions
six maternal factors
genetics disease nutrition stress placental toxicity exposure to xenobiotics
plays a central role in influencing embryonic exposure by helping to regulate blood flow, by offering transport barrier, and by metabolizing chemicals
placenta
the extent of transfer through the placenta depends on three things
the type of placentation
the physiochemical properties of the chemical
rates of placental metabolism
the passage of most drugs across the placenta occurs by
simple passive diffusion
originally prescribed as a sedative to reduce nausea in pregnancy
thalidomide
what was the toxicity of thalidomide
causes limb malformations
thalidomide causes
oxidative stress
activation to free radial intermediate
reduced binding of DNA factor needed to turn on genes for limb development
thalidomide critical period
20-36 days post fertilization
non-steroidal estrogen, used to prevent miscarriage
Diethylstilbestrol (DES)
what toxicity does DES cause
vaginal clear cell adenocarcinoma in females
testicular/semen problems in males
critical period of DES
first trimester
ethanol causes ____ at high doses
fetal alcohol syndrome
three deformations of FAS
craniofacial malformation
growth retardation
reduced intellectual development
toxicity effects with low doses of ethanol
loss of birth weight
loss of intellectual development
interferes with nuclear receptors causing cleft palate and schizophrenia
retinoids (vitamin A)
anti convulsant for epileptic patients that causes birth defects, spina bifida
valproic acid
