PSYCH 1 Chapter Notes - Chapter 5: Brainstem, Donald O. Hebb, Pituitary Gland
Document Summary
Brain consumes about 2% of average person"s body weight, but consumes about 20% of the person"s metabolic energy. Human brain contains roughly 80-100 billion nerve cells (neurons), and roughly 1 trillion point of communication, or synapses, between neurons. Brain and spinal cord make up central nervous system (cns) Extensions from central nervous system, called nerves, make up peripheral nervous system. Don"t confuse neuron and nerve; neuron is a single cell of the nervous system; a nerve is a bundle of many neurons within the peripheral nervous system. Myelin is a fatty substance produced by supportive brain cells called glial cells. Resting potential of a cell = -70 millivolts. Depolarization: na + moves into the axon, making inside positive. Repolarization: k + moves out of axon, reestablishing the resting potential. Myelination begins before a child is born but is not complete until some time in adulthood, during the third decade of life or beyond.
