subdivisions of embryology
descriptive
comparative
experimental
descriptive embryology
study of the mechanisms of development
comparative embryology
study that compares the development of one species to that of another species
experimental embryology
- study of external factors on development
- only area of embryology with active research
embryon
something that swells in the body
prenatal period
- before birth
- embryonic and fetal periods
embryonic period
0-8 weeks (most during weeks 3-8)
fetal period
8 weeks to birth
postnatal period
- after birth
- infancy, childhood, puberty, adolescence, adulthood
infancy
- 0-1 year
, - first 4 weeks = neonatal period
childhood
1-13 years
puberty
girls: 12-15 years
boys: 13-16 years
adolescence
- 12-17 years
- ability to reproduce
adulthood
18-death
ventral
toward the belly
dorsal
toward the back
cranial
toward the head
caudal
toward the tail
rostral
toward the nose
median (midsagittal) plane
equal right and left halves
sagittal plane
right and left sections
transverse plane (cross section)