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61 Cards in this Set

  • Front
  • Back
What is neurulation?
formation of CNS
Initial CNS primordia
Neural plate
Neural plate comes from
Notochord comes from
What tells the ectoderm to thicken into neural plate?
The neural plate becomes
Neural tube - it bends into it.
Where is intraembryonic mesoderm
on either side of notochord; between endoderm and ectoderm
the 3 layers of intraembryonic mesoderm on either side of notochord are:
-paraxial mesoderm
-intermed. mesoderm
-lateral mesoderm
paraxial mesoderm becomes
-skeletal muscles
-fibrous ct
intermediate mesoderm becomes
-reproductive ducts
-adrenal cortex
where does the notochord lie in all this?
Axial mesoderm
What is the first step in paraxial mesoderm development?
Segmentation into somites
what are somites?
Temporary - allow further segregation of precursor cells.
What do the somites develop into?
Birth defects cause how many deaths
Major birth defects are detected in how many infants
-at birth
-in childhood
birth = 1-2%
childhood = 4-6
advanced age is risk factor for:
maternal = downs

paternal = achondroplasia, apert's
Season of the year is associated with increased risk of:
anencephaly in infants conceived in ireland in spring months
country of residence is associated with
-increased anencephaly in celtic population
-thalidomide problems in europe where drug was sold
race is associated with what birth defects
-cleft palate - 2 x more commin in whites than blacks
-doesn't influence rate
polycdactyly is commin
when does a defect occur?
Emryonic period
when do disruptions occur
embyronic-fetal period
when do deformations occur?
late in fetal period
what is a defect?
morphological malformation resulting from abnormal developmental mechanisms or processes - intrinsic, can be inherited.
what is a disruption?
morpholog malformation resulting from a breakdown or interference with an ORIGINALLY NORMAL developmntl process.
are disruptions intrinsic or ex?
Extrinsic - can be made more susceptible to it by genetics tho.
what is deformation?
abnormality caused by nondisruptive mechanical force
what is a polytrophic field affect?
pattern of anomalies in a disturbed single field i.e. whole organ or body area.
what is a syndrome?
pattern of multiple primary anomalies seen together and causally related
what is a sequence?
pattern/cascade of 2' anomalies that result from a single primary anomaly or initiator
what is an association?
a nonrandom occurence of 2/more features, occur more often than expected by chance alone, idiopathic.
causes of abnormal development:
what are 2 types of genetic factors?
-chromosome problems
-gene mutations
2 ways chromsm's can be abnormal
-number - aneuploidy/polyploidy

what is aneuploidy?
ch' number is not exact multiple of hyploid number
what is polyploidy?
ch' number is exact multiple of haploid number - eg triploid
what is a dominant mutation vs. recessive?
recessive requires a double dose of gene mutation, dom only one
what is a teratogen
agent that can produce congeital anomaly or raise incidence of anomaly
what is teratology?
dysmorphogenesis - study of birth defects
what is worse; acute or chronic drug use?
What causes 20-25% of all birth defects?
multifactorial effects
What do multifactorial effects result from?
interaction of
-Genetic endowment
-developmental environmetn
What is the cause of most birth defects?
Give an example of anomalies caused by the following developmental disturbances:
Duplications and reversal of assymetry:
conjoined twins, situs inversus
Faulty inductive interactions
complete or partial absence of structures
absenc of normal cell death
webbed dgiits
failure of fusion or merging
facial clefting
disturbances in tissue resorption
duodenal or anal atresia
failure of migration
ectopic kidney
developmental arrest
cleft palat, thyroglossal duct cyst
hyperplasia and hypoplasia
overgrowth or undergrowth
defective fields
caudal regression
failure of tube formation
neural tube defects
destruction of formed structures
unilateral distortion of the face
receptor defects
germ layer defects
ectodermal dysplasias
secondary effects
First five A-list teratogens:
Last A list teratogens