Development and Teratogenesis Flashcards
Teratogens
Come from the outside
4 classes of teratogens and examples
Maternal illness (PKU, diabetes) INfectious agents (TORCH) Physical agents (radiation or heat exposure) Drugs (thalidomide, antiepileptic drugs)
Response ot teratogens
Highly individual and could have to do with a lot of different things such as route, timing, dose
All or nothing theory
In enough cells die, spontaneous abortion
If only a few cells die, others can compensate
Significant exposure to teratogens during days ________ post-conception may result in cell death
10-14
Day 27
Closure of neural tube
Day 30
Appearance of limb buds
Weeks 4 and 5
Branchial arches, clefts, piuches, and optic vesicle
Week 5 to 7
HEart and kidneys
Week 8
Mature limb architecture
Weeks 7 to 10
Internal and external genitalia
Week 10
Rotation into abdominal cavity
Teratogenesis occurs _______
After fertilization
Toxic mutagenesis
Exposure prior to conception causing mutations
Toxic mutagenesis females vs. males
Females - DNA replication occurs during oogenesis years before ovulation
Males - continous spermatogensis makes males more susceptible
Infectious agents mechanisms
Usually direct invasion of fetal tissues…lead to inflammation and cell death
Infectious teratogenic agents
TORCH, varicella, and parvovirus B19