Weibel’s Model of airwaysIn Lung Physiology

Weibel’s Lung modelDeveloped in 1963 by Weibel’s et al. as a symmetrical tree lung model for adult with 35 branching angle.Feature a symmetry in all tubes of the same generation with identical geometric parameter.Same number of tubes along each pathway.Simplest model of human lung and is widely used.

Weibel,1963 plastic cast

The cross-sectional area increases very rapidly.

The morphology of the human being was greatly clarified by the studies of Weibel’s.

Commonly used so called as Model-A.

It was the 23rd-generation model (1963).

Airway Generation Lung is made up of airway

call generation. Trachea is generation 0

(G0), this is a straight duct with ring structure

The upper bronchial consist of generations 1 to 16.

This is a series of branching “smooth” tube.

High flow in this region with large airway.

ICRP66 Respiratory Tracts Compartment dosimetry Model

Average no of terminal bronchioles=34856

Alveoli start appearing at generation 17.

Airways are much smaller and the wall with alveoli is no longer smooth.

This is a region of low flow and high residence time

Idealization of Human airways First 16 generations make up the conducting

airways ending in terminal bronchioles.

Next three generations ( 17,18,19 )constitute the Respiratory bronchioles.

Transitional Zone is a zone where degree of alveolation steadily increases.

Finally, three generations of Alveolar Ducts and one generation of Alveolar Sacs are there.

These last four zones constitute the True Respiratory Zone.

Tracheobronchial Tree

Tracheobronchial Tree It’s a Invasion of Primary Bronchus into hilum of the lungs and

their branching structure of airways supplying air to the lungs.

• Trachea divides into Right and Left Principle Bronchus • Each Principle Bronchus divides into Lobar Bronchus

• Each Lobar bronchus divides into Segmental Bronchus

• Segmental Bronchus divide the Lobes of the Lungs into smaller segments = Bronchio-pulmonary Segment

• Trachea – Principle Bronchus – Lobar Bronchus- Segmental Bronchus

TRACHEA

R.P.B L.P.B

S.L.B

M.L.B

I.L.B

S.L.B

I.L.B

C.B

L.B

COLORED = SEGMENTAL BRONCHUS

APICAL

POSTERIOR

ANTERIOR

APICAL

POSTERIOR

ANTERIOR

MEDIAL

LATERAL

SUPERIOR LINGULARINFERI

OR LINGULAR

Superior

Medial Basal

ANTERIOR BASAL

Post Basal

Post Basal

Lateral Basal Lateral

Basal

3 3 + 2

2 -5 5

RIGHT Lung

LEFT Lung

SUPERIOR LOBEMIDDLE LOBEINFERIOR LOBE

Trachea-bronchial Tree

No of Segmental Bronchus

References:-Link.springerChegg.comIvyroses.comBoundless.comTechmeanatomy.infoMed.mun.caMath.u-psud.fr