PSY100H1 Lecture Notes - Brainstem, Gyrus, Autonomic Nervous System
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PSY100H1 Full Course Notes
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Document Summary
Central nervous system (cns) brain, spinal cord. Communicate with other neurons through chemical signals. Dendrites, nucleus, cell body, axon, myelin sheath, node of ranvier, schwann cell, terminal buttons. Action potential neural impulse that passes along the axon & subsequently causes the release of chemicals from the terminal buttons. More negative inside the cell -70 millivolts. Excitatory signals increase the likelihood that the neuron will fire. Inhibitory signals decrease the likelihood that the neuron will fire. They do this by affecting the polarization of the cell. Neurons fire (generate action potential) if excitatory input reaches certain threshold. All-or-none principle neuron fires with same potency each time. But how frequently the neuron fires can vary. Neurons are polarized at rest resting membrane potential ~70 mv. The inside of cell more negative than the outside. Relatively more sodium (na+) outside and more potassium (k+) inside. If neuron reaches excitatory threshold will fully depolarize (ie fire )
