Biomaterial Database

Diameter, length and branching ratios in the bronchial tree. 1976

K Horsfield, and F G Relea, and G Cumming

This paper is concerned with morphology and pattern of branching in the bronchial tree and their interrelationships. Branching ratio (Rb), diameter ratio (Rd), and length ratio (R1) are the factors by which the number of branches, mean diameter and mean length increase in successive orders of branching. An analysis based on the concept of minimum work suggests that ideally Rd = R1/3 b, whilst geometric considerations suggest that R1 = R1/3 b. Thus Rd = R1. These theoretical results are compared with those obtained from measuring one human and six dog bronchial tree casts. Values obtained from the human lung are in close agreement with the predicted values, whilst in the dog lungs the agreement, though less good, is still close. Rb is determined antenatally, the reason for its particular value being unknown. Diameter and length of branches may be modelled postnatally by growth in a manner which ensures that Rd = R1 - R1/3 b.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D001980	Bronchi	The larger air passages of the lungs arising from the terminal bifurcation of the TRACHEA. They include the largest two primary bronchi which branch out into secondary bronchi, and tertiary bronchi which extend into BRONCHIOLES and PULMONARY ALVEOLI.	Primary Bronchi,Primary Bronchus,Secondary Bronchi,Secondary Bronchus,Tertiary Bronchi,Tertiary Bronchus,Bronchi, Primary,Bronchi, Secondary,Bronchi, Tertiary,Bronchus,Bronchus, Primary,Bronchus, Secondary,Bronchus, Tertiary
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia