Embryology Flashcards
(47 cards)
Produced at base of limbs in zone of polarizing activity.Involved in patterning along anterior-posterior axis. CNS development; mutationi = holoprosencephaly
Sonic Hedgehog Gene
Produced at apical ectodermal ridge (end of developing limb); Necessary for proper organization along dorsal-ventral axis
Wnt-7 gene
Produced at apical ectodermal ridge. Stimulates mitosis of underlying mesoderm, lengthening of limbs
FGF gene
Involved in segmental organization of embyro in a craniocaudal direction.
Homeobox genes
Mutation of this causes appendages in wrong locations
Hox gene
Day 0
fertilization
Day 2
zygote in fallopian tube
Day 3
Morula
Day 5
Blastocyst
Day 7-10
Implantation; when hCG secretion begins
2 weeks
Bilaminar disc; epiblast & hypoblast
3 weeks
Trilaminar disc; Gastrulation
Primitive streak, notochord, mesoderm and its organization, and neural plate begin to form
Embryonic period
3-8 weeks; neural tube forms by neuroectoderm and closes by week 4; organogenesis; extremely susceptible to teratogens
Week 4
heart begins to beat; upper and lower limb buds begin to form (4weeks; 4 limbs)
Week 5
Fetal cardiac activity visible by transvaginal ultrasound
Week 10
Genitalia have male/female characteristics
Process that forms the trilaminar embryonic disc. Establishes the ectoderm, mesoderm and endoderm. Starts with epiblast invaginating to form primitive streak
Gastrulation
Adenohypophysis (from Rathke pouch)
Surface ectoderm
Lens of Eye; olfactory epithelium; sensory organ of ear
Surface ectoderm
Anal canal below pectinate line
Surface ectoderm
Epithelial lining of oral cavity; parotid, sweat and mammary glands
Surface ectoderm
Neurohypophysis
Neuroectoderm
Retina and optic nerve
Neuroectoderm
CNS neurons, oligodendrocytes, astrocytes, ependymal cell pineal gland
Neuroectoderm
