Ch04 Flashcards
Three layers of a human embryo
Endoderm: Endo=in,within
mesoderm: meso= middle
ectoderm: ecto= outside
derm=skin
Ectoderm
outer layer; part becomes the nervous system
How is the neural tube formed?
the crests of the neural groove join
What are the anterior parts of the neural tube?
forebrain, midbrain, hindbrain
What are Neural tube defects (NTDs)
congenital malformations affecting the brain and spinal cord.
What is anecephaly
absence of the cranial vault, the covering skin and the brain tissue
an= without
enkephalos= brain
-aly= condition
Spina bifida
non-closure of the spine with exposure of the spinal cord and meninges
Encephalocele
meninges and brain tissue outside the cranium, covered by skin.
Dorsoventral patterning referes to what?
refers to the differentiation and specialization of the neural tube between the dorsal half and the ventral half separated by sulcus limitans
Motor neurons are regulated by what protein?
Sonic hedgehog protein (SHH) which is secreted by the notochord and basal plate cells
Sensory interneurons arise lateral to the alar plate in the dorsal half of the neural tube. This is regulated by?
bone morphogenic proteins (BMPs)
What is adult neurogenesis?
the generation of new neurons in adulthood, especially in the dentate gyrus
Development is governed by?
gene expression and modulated by environmental factors.
In human cortex, there is a ___ ____ of synapses from late childhood until mid adolesence.
net loss
What is amblyopia?
impairment of vision in one eye with inability to see clear forms.
Neuroplasticity: Hebbian synapses
grow stronger or weaker depending on their ability to affect a postsynaptic cell.
Neurotrophic factors
may play a role in the competition- active synapses take up more of the factor.
Genotype
the sum of an individual’s intrinsic genetic information; constant
Clones
asexually produced organisms that are genetically identical.
Phenotype
the sum of an individual’s physical characteristics; changes constantly based on extrinsic effects on genes
Identical twins
genes identical; differences in environment produce different neural phenotypes and different behaviors.
Epigenetics is the study of?
factors that change gene expression without changing the gene sequences
- methylation of DNA
- methylation of acetylation of histones
Methylation
a chemical modification of DNA without changing the nucleotide sequence; makes genes are less likely to be expressed.
Teratogen
chemical or physical agent that can cause birth defects or increase the risk of birth defects in a developing fetus.
