The pleurae
- Each pleura has two parts
- Parietal layer - lines thorax wall and diaphragm
- Visceral layer - covers outer surface of lungs
- Continuous with each other at root of lung
- Separated by pleural cavity containing a small amount of pleural
fluid
- Pulmonary ligaments at each lung root allow for movement during
respiration
- Costal pleura is supplied by intercostal nerves
- Mediastinal pleura is supplied by phrenic nerves
- Diaphragmatic pleura is supplied by both intercostal and phrenic
nerves
The trachea
- Fibroelastic wall with U-shaped hyaline cartilages
- Begins below cricoid cartilage at level of C6 vertebra
- Ends at level of sternal angle at level of T4 vertebra
- Lies in superior mediastinum
The bronchi
- Right main bronchus is wider, shorter and more vertical than the
left
- Divides at hilum of right lung into 3 branches
- Left main bronchus passes in front of the oesophagus
- Divides at hilum of left lung into 2 branches
The lungs
- Each lung is conical in shape
- Covered by visceral pleura
- Attached to mediastinum by the root
- Apex extends into the root of the neck
- Base of the lung overlies the dome of the diaphragm
- Right lung has 3 lobes - upper, middle and lower
- Left lung has 2 lobes - upper and lower
- Lobes of the lung are divided into bronchopulmonary segments
- Each receives a segmental bronchus, artery and vein
- Blood supply of the bronchi and their branches are from the
bronchial arteries
- Bronchial arteries are direct branches of the aorta
- Bronchial veins drain into the azygos and hemiazygos veins
- Deoxygenated blood enters each lung via the pulmonary artery
- Oxygenated blood leaves each lung via the pulmonary vein
- At each lung root is the pulmonary venous plexus
- Sympathetic efferent fibres produce bronchodilatation
- Parasympathetic efferent fibres produce bronchoconstriction
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