Abstract
From physical point of view, breathing process is a flow of air through a system of tubes and other specific parts. During breathing, the direction of the flow changes periodically.
Between the turns, the flow is interrupted. During all phases of breathing, respiratory system produces noise which includes specific phenomena depending on properties of the respiratory system and breathing conditions.
All this suggests that an appropriate analysis of respiratory sound recordings may prove very helpful in diagnosis in some conditions, when conventional methods do not provide reliable results.