The Structure of the Neuron
A typical neuron has four morphologically defined regions: dendrites (receiver)(1) , cell body (2), axon (3), and presynaptic terminals (transmitter)(5).
Neurons receive nerve signals from axons of other neurons. Most signals are delivered to dendrites (1). The signals generated by a neuron are carried away from its cell body (2), which contains the nucleus (2a), the storehouse of genetic information. Axons (3) are the main conducting unit of the neuron. The axon hillock (2b) is the site at which the cell's signs are initiated. Schwann cells (6), which are not a part of a nerve cell, but one of the types of glial cells, perform the important function of insulating axons by wrapping their membranous processes around the axon in a tight spiral, forming a myelin sheath (7), a fatty, white substance which helps axons transmit messages faster than unmyelinated ones.The myelin is broken at various points by the nodes of Ranvier (4), so that in cross-section it looks rather like a string of sausages. Branches of the axon of one neuron (the presynaptic neuron) transmit signals to another neuron (the postsynaptical cell) at a site called the synapse (5). The branches of a single axon may form synapses with as many as 1000 other neurons. Axion terminals and dendrites do not actually touch, brain chemicals called neurotramsmitters carry information across the synaptic gap.
Ψ Remember, early brain growth is rapid & widespread, This phenomenal increase is called transient exuberance.
Ψ Experience enhances the brain.
• Experience-expectant brain functions require basic common experiences in order to develop, therefore each person will be similar to every other person (human).
• Experience-dependent brain functions depend on particular, & variable, events that occur in some families & cultures but not in others. Infants brains are structured /wired depending on which experiences are present during development,
consequently each person will be unique to a particular family & culture.
Growth & Development|
Robert C. Gates