How does the nervous system develop and adapt? Flashcards
testosterone
Sex hormone secreted by the testes and responsible for the distinguishing characteristics of the male.
tropic molecule
Signaling molecule that attracts or repels growth cones.
filopod (pl. filopodia)
Process at the end of a developing axon that reaches out to search for a potential target or to sample the intercellular environment.
gene (DNA) methylation
Process in which a methyl group attaches to the DNA sequence resulting in the suppression of gene expression.
growth cone
Growing tip of an axon.
subventricular zone
Lining of neural stem cells surrounding the ventricles in adults.
glioblast
Product of a progenitor cell that gives rise to different types of glial cells.
netrin
Member of the only class of tropic molecules yet isolated.
apoptosis
Cell death that is genetically programmed.
neural Darwinism
Hypothesis that the processes of cell death and synaptic pruning are, like natural selection in species, the outcome of competition among neurons for connections and metabolic resources in a neural environment.
anencephaly
Failure of the forebrain to develop.
chemoaffinity hypothesis
Proposal that neurons or their axons and dendrites are drawn toward a signaling chemical that indicates the correct pathway.
estrogens
Variety of sex hormones responsible for the distinguishing characteristics of the female.
amblyopia
Condition in which vision in one eye is reduced as a result of disuse; usually caused by a failure of the two eyes to point in the same direction.
neurotrophic factor
A chemical compound that acts to support growth and differentiation in developing neurons and may act to keep certain neurons alive in adulthood.
imprinting
Process that predisposes an animal to form an attachment to objects or animals at a critical period in development.
autism spectrum disorder (ASD)
Range of cognitive symptoms, from mild to severe, that characterize autism; severe symptoms include greatly impaired social interaction, a bizarre and narrow range of interests, marked abnormalities in language and communication, and fixed, repetitive movements.
neural plate
Thickened region of the ectodermal layer that gives rise to the neural tube.
androgen
Class of hormones that stimulates or controls masculine characteristics.
masculinization
Process by which exposure to androgens (male sex hormones) alters the brain, rendering it identifiably male.
progenitor cell
Precursor cell derived from a stem cell; it migrates and produces a neuron or a glial cell.
neural stem cell
Self-renewing, multipotential cell that gives rise to any of the different types of neurons and glia in the nervous system.
neuroblast
Product of a progenitor cell that gives rise to any of the different types of neurons.
radial glial cell
Path-making cell that a migrating neuron follows to its appropriate destination.
critical period
Developmental ‘window’ during which some event has a long-lasting influence on the brain; often referred to as a sensitive period.
sudden infant death syndrome (SIDS)
Unexplained death while asleep of a seemingly healthy infant less than 1 year old.
neural tube
Structure in the early stage of brain development from which the brain and spinal cord develop.
growth spurt
Sporadic period of sudden growth that lasts for a finite time.
cell-adhesion molecule (CAM)
A chemical molecule to which specific cells can adhere, thus aiding in migration.
