PS263 Chapter Notes - Chapter 4: Hindbrain, Neuroglia, Neural Tube
Document Summary
Human central nervous system begins to form when embryo is about 2 weeks. Soon becomes neural tube that surrounded fluid filled cavity which becomes central canal of spinal cord and 4 ventricles of brain. As tube sinks under skin, forward end enlarges and differentiates into hindbrain, midbrain and forebrain. We start making movements before we start receiving sensations. Primitive neurons begin to migrate/move early in development. Migration guided by chemicals immunoglobulins and chemokines: differentiation: Glia produce fatty insulating sheaths that accelerate transmission. Social isolation produces part of effect by impairing myelination: synaptogenesis: Humans do not make new neurons in olfactory bulbs like rodents do. Growing axon follows path of cell surface molecules. Axon is attracted by some chemicals and repelled by others in process that steers axon in correct direction. Eventually axons sort themselves over surface of target area by following a gradient of chemicals.
