Hereditary neuropathies are diseases of the peripheral nerves that are genetically passed from parent to child. The most common of these is Charcot-Marie-Tooth disease type 1. It is characterized by weakness in the legs and, to a lesser degree, the arms -- symptoms that usually appear between mid-childhood and age 30.
1 Chlorine ions are colored yellow in the VRML model. 2  Sodium (Na +) and potassium (K +) are positive ions. 3  They are found on both sides of the membrane. 4  Na + ions are in greater concentration outside the neuron whereas K + ions are more concentrated inside the neuron. 5  Na + ions are colored pink in the VRML model.
1 The outward movement of positive potassium ions makes the inside of the membrane more negative and returns the membrane toward the resting membrane potential (repolarizes the cell). 2  When the membrane potential returns to the resting value, the potassium channels shut down and potassium ions can no longer leave the cell. As we discussed, the inside of the cell is slightly negatively charged (resting membrane potential of -70 to -80 mV). 2  A disturbance (mechanical, electrical, or sometimes chemical) causes a few sodium channels in a small portion of the membrane to open.