Fröhlich systems in cellular physiology

Electromagnetic fields are usually absent in the picture of processes taking place in living cells which is dominated by biochemistry, molecular genetics and microscopic morphology. Yet experimental and theoretical studies suggest that this omission is not justified. At the end of 1960's H. Fröhlich elaborated a semi-phenomenological model of polar oscillating units that are metabolically driven, exchange energy with the cell's internal heat reservoir, and store part of the energy in excited vibrational modes in such way, that mode with the lowest frequency becomes highly excited, while the higher-order modes remain near thermal equilibrium. This affords energy-hungry chemical reactions to take place while the rest of the cell is not exposed to heat stress. At present, part of the cytoskeleton - microtubules - are deemed to fulfil the role of oscillating units. The paper provides an introduction to the Fröhlich ideas for readers with background in medicine and biology in that it avoids mathematical formulas and relies on figures to convey information about the basic properties of the model. The essential features of the Fröhlich model - most notably the energy condensation - are demonstrated on ensemble encompassing three coupled vibration modes that can be exactly described using original diagrammatic method.