Lung Anatomy

CPC – 12.11.2014

Anatomy of the Lung

Weibel 1984

Warm up – guessing lung numbers

• Average weight

• Surface area:

• Cummulated length of airways:

• Number of alveoli:

• Cummulated length of lung campilares:

• Thickness of air-blood barrier

• 1,3 kg

• ~40-100 m2

• 2400 km

• 300-500 million

• 1000 km

• 0.6 µM

Content

1. Structure of the lung

2. Muscles of the lung

3. Pulmonary circulation

4. Mouse lung anatomy

Position of the lung

OpenStax College - Anatomy & Physiology,

Lung lobes

• Right Lung: 3 Lobes; Left Lung: 2 Lobes

• Relatively independent functional units within the lung

• Inserted by secondary bronchi

Bronchiopulmonary segments

• Right Lung: 10; Left Lung: 8

• Pyramidal shaped independent units of the lung

• Each segment has it‘s own pulmonary artery / Veins run in intersegmental areas

• Inserted by tertiary bronchi

Pulmonary lobules

• Hexagonal divisions seperated by septae

• Inserted by terminal bronchioles

http://radiopaedia.org

Acinus

• Distal to the terminal bronchioles

• Contains respiratory bronchiole, alveolar sacs, and alveoli

http://cnx.org

Alveoli

Summary

The lung structure is defined by the branching of the bronchial tree

• Lung lobes

Right lung 3, left lung 2

Inserted by secondary bronchi

• Bronchiopulmonary segments

Right lung 10, left lung 9

Inserted by tertiary bronchi

Each one inserted by a pulmonary artery

Seperated through layer of connective tissue containing pulmonary veins

• Pulomnary lobule

Hexagonal divisions seperated by septae

Inserted by terminal bronchioles

• Acini

Distal of the terminal bronchiole

Comprising the respiratory bronchioles, alveolar sacs and alveoli

One pulmonary lobe consists of up to 12 acini

The bronchial tree

The bronchial tree

http://open.umich.edu/education/med/resources/second-look-series/materials

The bronchial tree

The lung epithelium

But how does it really look

Respiratory Muscles

inspiratory muscles

neck musculature

diaphragm

expiratory muscles

abdominal musculature

Pulmonary circulation

Mouse & Rat

Left lung: 1 lobe

Right lung: 4 lobes

Treuting, Dintzis, Comparative Anatomy and Histology: A Mouse and Human Atlas

The lobulation is independent of body size

Airway branching pattern

Airway branching pattern

Mouse Human

Total lung capacity 1ml 6l

Lobes 5 (4 right, 1 left) 5 (3 right, 2 left)

Airway branching pattern Monopodial (irregular) Dichotomus (symmetrical)

Airway generations 15-20 20-25

Blood-gas barrier ca. 0.3 µM ca. 0.6 µM

Alveoli size (MLI) ca. 80 µM ca. 200 µM

Respiratory rate (breaths per minute)

250–350 bpm 12-20 bpm

Irvin, Bates Respir Res. 2003;4:4. Epub 2003 May 15

Thanks for your attention!