Biophysics of nerves

摘要: A characteristic property of living organisms is excitability, that the ability to react upon a stimulus from without. Changes in immediate environment organism (a stimulus) evoke specific changes itself or some parts it response). clear example phototaxis, light-triggered movement photosynthetic microorganisms (see Chapter 10). Another contraction muscle fiber an electric stimulus. In all these cases response rapid (in order milliseconds). Although can also have relatively slow responses its (for instance induced synthesis enzyme substrate concentration, which takes minutes even hours), term excitability reversed for fast responses. All such phenomena seem be closely associated with distribution charge across membranes, particularly cytoplasmic membrane.