PS101 Study Guide - Midterm Guide: Myelin, Axon Terminal, Glial Scar
Document Summary
Neurons have a cell body filled w cytoplasm that contains a nucleus (the residence of chromosomes that contain the genetic material) Neurons contain organelles that enable the neuron to make proteins, produce energy and permit the breakdown and elimination of toxic substances. A two-molecule thick neuron membrane completely covers cell body, dendrites and axon. 86 billion in brain, however in some parts glia may outnumber neurons by 10:1. Control nutrient supply, destroy diseased and dead neurons, provide axons w myelin sheath. Migrate to site of brain injury and enlarge + multiply to form a glial scar. Happens locally rather than interacting with the brain, allows for quick movement. In order to move hand away from a burn, you have to feel the burn first. Signal does travel to the brain, but is not required. In people who are paralyzed, these reflexes may still work. Receives enough neuron input and either fires or doesn"t.
