chapter 4: development of the brain Flashcards
ectoderm
outer layer of the developing embryo, giving rise to the skin and the nervous system
neural tube
embryonic structure with subdivisions that correspond to the future forebrain, midbrain, and hindbrain
neurogenesis
production of neurons
mitosis
cell division
ventricular zone
a region lining the cerebral ventricles from which new neurons and glial cells are born throughout life, via mitosis
cell migration
movement of cells from site of origin, out of the ventricular zone, to final location, where they express particular genes
gene expression
the way a cell makes an mRNA transcript of a gene. cells begin to use, or express, particular genes
cell differentiation
cells become distinctive types of neurons or glial cells through cell-cell interactions
synaptogenesis
establishment of synaptic connections as axons and dendrites grow
cell-cell interactions
process during development in which one cell affects the differentiation of other cells
stem cells
undifferentiated and therefor can take on the fate of any cell that a donor organism can produce
cell death (apoptosis)
surplus cells die (needs to happen)
neurotrophic factors
target-deprived chemical that induces innervating neurons to survive
synapse rearrangement (synaptic remodeling)
loss of synapses and the development of others
fragile X syndrome
intellectual disability produced by a fragile site on the X chromosome that seems prone to breaking because the DNA there is unstable
amblyopia
reduced visual acuity of one eye that is not caused by optical or retinal impairments
binocular deprivation
depriving both eyes of form vision, as by sealing the eyelids
monocular deprivation
depriving only one eye of light during the developmental sensitivity period, resulting in structural and functional changes in the thalamus and visual cortexo
ocular dominance histogram
portrays the strength response of a brain neuron to stimuli presented to the eyes
Hebbian synapse
a synapse that is strengthened when it successfully drives the postsynaptic cell
radial glial cells
scaffold for neurons to follow to reach target destination
holoprosencephaly
atypical separation of the two hemispheres of the forebrain and can disrupt development of midline facial structures
growth cone
specialized structure at the end of a growing axon deciding where to grow
lamellipodium
sheet like expansion of the growing axon
filopodia
numerous fine processes in the tip of the axon
genotype
all genetic information that one specific individual has inherited (intrinsic, since birth)
phenotype
anatomical, physiological and behavioral characteristics (extrinsic, changes constantly)
phenylketonuria(PKU)
absence of the enzyme necessary to metabolize phenylalanine resulting in a buildup of phenylalanine, which becomes toxic
epigenetics
study of factors that affect gene expression without making any changes in the nucleotide sequence of the genes
methylation
a chemical modification of DNA that does not affect the nucleotide sequence of a gene but makes that gene less likely to be expressed
Alzheimer’s disease
form of dementia that may appear in middle age but is more frequent among the aged
dementia
drastic failure of cognitive ability, including memory failure and disorientation
amyloid plaques
buildup of beta-amyloid (proteins)
neurofibrillary tangles
abnormal whorls of neurofilaments that form a tangled array inside the cell
