title: Discussion on basic equations for a flow in human air passages and their representation.
abstract: Basic equations of time-dependent flow are discussed in the case of rigid or elastic branches and according to the airway representation pattern, both continuous and discontinuous. Two relevant fundamental continuous functions are defined: the 'order of generation' G(x) and the cumulative bronchial diameter D(x). A numerical solution is outlined in the former case, then in the latter case, and the system of equations which completely describes the flow is solved.
mesh_terms: D001980:Bronchi / Q000033:anatomy & histology / Q000502:physiology; D004548:Elasticity; D006801:Humans; D008954:Models, Biological; D012119:Respiration; D012143:Respiratory Physiological Phenomena; D012137:Respiratory System / Q000033:anatomy & histology; D013997:Time Factors