CAPS 301 Lecture Notes - Winter 2018 Lecture 4 - Schwann cell, Proportionality (mathematics), Rate limiting
21 Sep 2018
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Capacitor: 2 conductive plates separated by an insulating layer; has the ability to store electrical charge. To get the inside negative, there must be a positive charge inside the capacitor. Insulating layer is thin, so can store charge. Repels the positive charge on the outside. Reorganizes charge on the capacitor (takes time; not instantaneous) Changing the charge on membrane surfaces (conductive plates of the capacitor) during the propagation of an electrical potential takes time. V_m gradually changes as the charge separation across the capacitor changes (gradual depolarization) Rate limiting step of ap = time it takes to reorganize the charge across membrane as capacitor. = less time to charge membrane threshold. Axons reduce membrane capacitance by inc. effective thickness of membrane (dis. Myelin: for ap conduction velocity; can inc. up to 50x faster. Formed by schwann cells in the pns, oligodendrocytes in cns.
