How Does the Nervous System Communication Work?
A. Nerve impulses travel within neuron, to other neurons and to effectors B. Nerve signal transmission within neuron-signal travels as series of changes in electrical activity at plasma membrane of axon. 1. Contains protein channels in membrane that can open and close. 2. In resting state, greater positive charge outside of cell, more negatively charged ion inside; higher Na+ concentration outside, higher K+ concentration within. 3. Difference in charge across membrane creates membrane potential, stemming from potential energy inherent in charge separation. 4. In response to stimulation: a) Membrane sodium channels open transiently, sodium ions gush in briefly. b) Influx of Na+ makes inside more positive relative to outside; this triggers opening of potassium channels. c) Potassium ions leave cell through opened channels, returning region of membrane to original resting membrane potential. III. The Spinal Cord A. Basic structure and function of spinal cord: 1. Acts as communication cen
