Fetal landmarks Flashcards
state the timeframe in which these landmarks are reached in the developing embryo
fertilization, zygote formation
Day 0
blastocyst implants, hCG secretion begins
Day 6
Bilaminar disk (epiblast, hypoblast)
Week 2
Trilaminar disk (gastrulation). Primitive streak, notochord, mesodermal organization, and neural plate begin to form.
Week 3
Embryonic period: neural tube formed, organogenesis, extrememely susceptible to teratogens.
Weeks 3-8
Heartbeat begins, neural tube closes, limb buds begin to form.
Week 4
What tissue makes up the neural tube?
Neurectoderm
Fetal period begins: movement, baby-like appearance
Week 8
Genitalia have male or female characteristics.
Week 10
What part of the neural tube do sensory neurons of the spinal cord come from?
Alar plate/lamina (caudal)
What part of the neural tube do spinal motor nerves come from?
Dorsal plate
