Repro I Flashcards
sonic hedgehog
patterning A/P direction
CNS - mutation holoprosencephaly
WNT-7 gene
at apical ectoderm ridge
-development alongs dorsal ventral axis
of limbs
FGF gene
apical ectoderm ridge
stimulate mitosis underlying mesoderm
-for lengthening of limb
Hox gene
hmoeobox
segmental organization in embryo
code transcription factors
mutation - appendage wrong location
early fetal development
day 0 - fertilization - form zygote
week 1 - hCG secretion begin after implant
week 2 - bilaminar disc form - epiblast/hypoblast
week 3 - trilaminar disc - 3 layers
-primitive streak, notochord, mesodem - neural plate forms
week 4 - 8 - neural tube formed and closes
-organogenesis begins
-susceptible to teratogens
week 4 - heart beat
-upper and lower limb buds form
week 6 - fetal cardiac acivity - seen by U/S
week 10 - genitalia male/female
gastrulation
forms trilaminar embryo disc
establish ectoderm, mesoderm, endoderm
start epiblast invagination to form primitive streak
ectoderm
surface ectoderm
neuroectoderm
neural crest
surface ectoderm
epidermis adenohypophysis lens of eye epithelial lining oral cavity sense organs of ear olfactory epithelium epidermis anal canal below pectinate parotid, sweat, mammary gland
neuroectoderm
brain - CNS neuron, oligodendrocytes, astrocytes, ependymal cells, pineal gland
neurohypophysis
retina
optic nerve
spinal cord
neural crest
PNS - dorsal root ganglia, CN, celiac ganglion, schwann cells ANS melanocytes chromaffin cells of adrenal medulla parafollicular cells of thyroid pia and arachnoid bones of skull odontoblasts aorticopulmonary septum
mesoderm
muscle bone CT serous linings spleen** CV structure lymph blood wall gut tube vagina kidney adrenal cortex dermis testes ovaries
notochord
induce ectoderm to form neuroectoderm (neural plate)
derivative - nucleus pulposus
endoderm
gut tube epithelium
urethra
luminal epithelial derivatives
-lung, liver, gallbaldder, pancreas, eustachian tube, thymus, parathyroid, thyroid follicular cells
agenesis
absent primordial tissue
aplasia
primordial tissue - but absent organ
deformation
extrinsic disruption
disruption
2ndary breakdown previously normal tissue
malformation
intrinsic disruption - during week 3-8
sequence
abnormality from single embryo event
teratogens
most susceptible - 3-8 weeks
before week 3 - all or none
after week 8 - altered growth/function
ACE I
teratogen - renal damage
alkylating agent
teratogen - absent digits, multiple anomalies
CN 8 toxicity teratogen
aminoglycoside
facial dysmorphism, develop delay, neural tube defect, phalanx/fingernail hypoplasia teratogen
carbamazepine
