The neuron -building block of nervous system. -100 billion neurons (nerve cells) -collect and send information (to and from sensory organs, glands, and other neurons) Neuron structure -dendrite (treelike): receives information -cell body (soma): contain nucleus and keeps the cell alive -axon (a long, segmented fiber): transmits information to another neuron -myelin sheath (cover axon): fatty tissue, insulation, and speeds transmission Communication -communication is an electrochemical process. -messages move through cells electrically -messages move between cells chemically -chemicals that relays (transmit) signals across synapses (the spaces between the cells) are called neurotransmitters. Synapse -terminal button: end of axon; releases chemicals -synapse: Small gap between neurons Neurotransmitter chemicals cross this gap -receptor site Receiving end of dendrite Neurotransmitters must fit the shape of receptor to cause a neuron to fire.
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- Fall '19