[The role of biological sciences in understanding the genesis and a new therapeutic approach to Alzheimer's disease].

The paper contrasts the historical view on causal factors in Alzheimer's disease (AD) with the modern concept of the symptoms' origin. Biological sciences dealing with cell structure and physiology enabled comprehension of the role of mitochondrial defects in the processes of formation of neurofibrillary tangles and β-amyloid, which in turn gives hope for developing a new, more effective therapeutic strategy for AD. It has been established that although mitochondria constantly generate free radicals, from which they are protected by their own defensive systems, in some situations these systems become deregulated, which leads to free radical-based mitochondrial defects.