Neurogenesis and Neural Migration

Neurogenesis

Process of forming new neurons

Neural tube

Contains multipotent neuronal stem cells

Neurons

Specialized nerve cells that conduct messages

Glial cells

Provide support for neurons

Progenitor neuroblasts

Produce neurons

Post-mitotic

Neurons that do not proliferate after embryogenesis

Neural migration

Movement of immature neurons to adopt final positions

Ventricular zone

Layer of tissue containing neural stem cells

Cortical plate

Layers of tissue that develop into the cerebral cortex

Immature neuron

Consists of a cell body, axons, and dendrites

Axon growth cone

Tip of an axon that contains growth filaments

Chemical stimuli

Control the direction of axon growth

Types of neurons

Unipolar, pseudounipolar, bipolar, multipolar

Sensory neurons

Transmit information from tissues and organs to the CNS

Motor neurons

Transmit information from the CNS to effectors

Interneurons

Transfer signals between sensory and motor neurons

Nervous system

Coordinates actions via transmission of electrochemical signals

Central nervous system

Brain and spinal cord

Peripheral nervous system

Peripheral nerves that link the CNS to receptors and effectors

Integration

Central nervous system integrates information from peripheral nerves

Reflex actions

Certain responses mediated by the spinal cord

Subdivisions of the nervous system

CNS, PNS (sensory and motor pathways), somatic and autonomic (sympathetic and parasympathetic) responses

Glia

Non-neuronal cells of the brain and nervous system

Astrocytes

Maintain blood-brain barrier and chemical environment

Oligodendrocytes

Myelinate axons in the CNS and provide structural framework

Ependymal cells

Line ventricles and central canal, involved in cerebrospinal fluid production

Microglia

Remove debris, wastes, and pathogens

Schwann cells

Myelinate axons in the PNS

Satellite cells

Regulate nutrient and neurotransmitter levels around neurons