Development and Teratogenesis Flashcards
Types of teratogens
-Pharmacological
-Infectious agents
-Industrial agents
-Recreational
Pharmacological
-Thalidomide
-Diethylstillbestrol
-Retinoic acid
Infectious agents
-Toxoplasma gondii
-Rubella
-Cytomegalovirus
-Herpes
-Congenital syphilis
-Zika virus
Industrial agents
-Lead
-Mercury
-Pesticides/herbicides
Recreational
-Alcohol
-Tobacco
-Cocaine
Principles of teratology
- Susceptibility to teratogens is variable
- Susceptibility to teratogens is specific for each teratogen
- The mechanism of teratogenesis is specific for each teratogen
- Teratogenesis is dose dependent
- Teratogens produce death, growth retardation, malformation, or functional impairment
Critical period for teratogenic effects
3-16 weeks of gestation
FAS s/s
-Behavioral disturbances
-Brain defects
-Cardiac defects
-Spinal defects
-Craniofacial anomalies
Fetal stage
-Organ development is completed
-Begins in 8th week of pregnancy and ends at parturition (birth)
-Increased length from 2.5 cm to 35-50 cm
-Increased weight from 1 g to 3000-4000 g
-Features are more humanlike
Congenital abnormalities
-31% of all successful fertilizations end in miscarriage of spontaneous abortions
-66% of these occur before women is aware she is pregnant
-Between 10-12% of all newborns have some kind of birth defects
Chromosomal aberrations definition
Changes in # of structure of chromosomes
Chromosomal abberations examples
-Trisomies (down syndrome)
-Monosomies
-Structural chromosomal aberrations
Genetic conditions causes
-Fetal and maternal genotype
-Mutations in specific genes
Genetic factors
-Roles of genes in development
-Gene expression and regulation
-Key developmental genes (eg HOX)
Environmental factors
-Drugs and medications
-Alcohol
-Infections
-Chemical exposure
