Lecture 4 - Nervous System Development Flashcards
Neural Plate
Within 18 days after conception, this primitive neural tissue forms that will give rise to the neural tube.
Neural Groove
Within 21 days after conception, this fold in the neural plate forms. It will eventually curl and become the neural tube.
Neural Tube
Within 23 days after conception, this structure forms when the neural plate collapses inward along the length of the embryo’s dorsal surface. The cells along this tube will eventually birth the whole of the nervous system.
Neurogenesis
The first stage of prenatal neural development in which pluripotent neural stem cells lining the neural tube begin their development into specialized neural cells. (Occurs throughout the lifespan in the hippocampus).
Cell Migration
The second stage of prenatal neural development in which the newly formed neurons and neuroglia make their way to the correct destination.
Cell Differentiation
The third stage of prenatal neural development in which neurons and glia assume their specialized cell types. This is accomplished through a series of chemically induced alterations in gene expression, resulting in the production of different proteins, and thus, cell differentiation.
Cell Maturation
The fourth stage of prenatal neural development which is defined by the growth of dendrites and axons.
Synaptogenesis
The fifth stage of prenatal neural development which is defined by the formation of synapses. (Continues throughout the lifespan).
Synaptic Pruning
The sixth stage of prenatal neural development in which functionally irrelevant connectivity weakens and becomes lost. The reasons for this are myriad; the most convincing rationale suggests that synaptic pruning supports the human organism in adapting to the environment. (Remnants of synaptic pruning continue until about the age of 20).
Myelinogenesis
The seventh stage of prenatal neural development that continues into early adulthood. After neurogenesis is complete, neuroglia begin to specialize and myelinate the axons of the recently developed neurons.
Epigenetics
The study of factors that affect gene expression without making any changes in the nucleotide sequence itself.
Experience-Driven Neural Activity
The idea that experience (pre- and post-natally) affects the organization of neural connectivity.
Dementias: Degenerative & Non-Degenerative
Drastic and persistent cognitive impairment, including deficits in memory and the impairment of social functioning. Degenerative dementias tend to be traceable to the nervous system. Non-Degenerative dementias have many diverse causes, but almost always involve the cardiovascular system.
Alzheimer’s Disease
A physical form of dementia in which amyloid plaques and neurofibrillary tangles cause atrophying in the cortical regions of the brain and in the hippocampus.
Parkinsons’s Disease
A physical form of dementia in which the degeneration of the Substantia nigra and the attendant loss of dopamine produced there causes tremors, rigidity, loss of spontaneous movement, and postural disturbances.
