ELECTRICAL IMPEDANCE AND EQUIVALENT BIOLOGICAL TISSUE CIRCUIT (ANALYSYS AND MODELING)
Keywords:
biological tissue, biological object impedance, construction principle, equivalent electrical circuit, modelingAbstract
In biological objects, purely electronic conductivity is absent, because they are primarily either dielectrics or solutions of electrolytes (blood, cytoplasm, various tissue fluids). A feature of biological fluids is that, in addition to electrolyte solutions, their composition includes proteins and fats, therefore their specific resistance to direct current is quite large. Besides that, cell membranes have a significant effect on the electrical properties of tissues and cells. The measurement of the electrical resistance of tissues and organs is difficult for the following reasons: biological objects have a different configuration, and the appliance of the formula assumes the presence of a homogeneous electric field between the electrodes; tissues and organs are heterogeneous in their composition, and the current flows mainly in those areas whose resistance is less.
The peculiarities of different types of biological tissue, the principles of electric circuit constructions are revealed. These principles have allowed constructing biological tissueequivalent electrical circuits by using two and three elements. The most commonly used electrical circuits of biological tissues, as well as their impedance phrases are introduced.
An analysis of the adequate circuits and simulation of the MATLAB software environment are performed, as well as the modelling results are implemented.
