PSYC 2060U Study Guide - Midterm Guide: Positron Emission Tomography, Myelin, Central Nervous System
Document Summary
Soma: cell body; body of the neuron. Axon: carries information away from the cell body. Axon terminals: branches that link the dendrites and soma of the other neurons. Myelin sheath: many axons are covered with a tube-like myelin sheath. Allows electrical conduction to skip from node to node (300 km/hour: nodes of ranvier. Intervals where the myelin sheath is either thin or absent. Neural communication: fluid inside & outside neurons. Contain electricity charged ions: neurons at rest have a negative charge, stimulation causes cell membrane to open briefly. Positively charged sodium ions shift in electrical charge travels along the neuron. Each neuron is sent excitatory" and inhibitory" signals from other neurons. Excitatory signals bring the neuron closer to its threshold. Inhibitory signals move the neuron away from its threshold. Chemical messengers that diffuse across synapses and activate receptor sites on adjacent cells. Exitatory: cause depolarization, cause inflow if sodium or other (+ ions)
