Pleural cavity
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| Pleural cavity | |
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| Front view of thorax, showing the relations of the pleuræ and lungs to the chest wall. Pleura in blue; lungs in purple. | |
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| A transverse section of the thorax, showing the contents of the middle and the posterior mediastinum. The pleural and pericardial cavities are exaggerated since normally there is no space between parietal and visceral pleura and between pericardium and heart. | |
| Latin | cavitas pleuralis |
| Gray's | subject #238 1088 |
| Precursor | intraembryonic coelom |
| MeSH | Pleural+Cavity |
| Dorlands/Elsevier | c_16/12220581 |
In human anatomy, the pleural cavity is a body cavity containing the lungs; the lungs are surrounded by two serous membranes, the pleurae. The outer pleura (parietal pleura) covers and is attached to the chest wall. The inner pleura (visceral pleura) covers and is attached to the lung and other structures, i.e. blood vessels, bronchi and nerves. Between the two is a thin space known as the pleural space, which normally contains a small amount of pleural fluid.
The parietal pleura is highly sensitive to pain; the visceral pleura is not, because it receives no nerves of general sensation.[1]
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[edit] Functions
Pleural fluid serves several functions. It lubricates the pleural surfaces and allows the pleural layers to slide against each other easily during ventilation. Pleural fluid also provides the surface tension that keeps the lung surface in close apposition with the chest wall. This allows optimal inflation of alveoli during respiration. It also directly transmits pressures from the chest wall to the visceral pleural surface (and hence, the lung). Therefore, movements of the chest wall during breathing are coupled closely to movements of the lungs.
[edit] Blood supply
The visceral pleura has a dual blood supply from the bronchial and pulmonary arteries.
[edit] Fluid
It is filled with pleural fluid, a serous fluid produced by the pleura. A normal 70 kg human has approximately 12-15 mL of pleural fluid.
In normal pleurae, most fluid is produced by the parietal circulation (intercostal arteries) via bulk flow and reabsorbed by the lymphatic system. Thus, pleural fluid is continuously produced and reabsorbed. The rate of reabsorption may increase up to 40x before significant amounts of fluid accumulate within the pleural space.
In humans, there is no anatomical connection between the left and right pleural cavities, so in cases of pneumothorax (see below), the other hemithorax will still be able to function normally.
[edit] See also
- Pleural disease
- Vertebrate trachea
- Capillaries
- Larynx
- Pharynx
- Epiglottis
- Rings of cartilage
- Bronchus
- Bronchioles
- Thoracic cavity
[edit] Additional images
 The position and relation of the esophagus in the cervical region and in the posterior mediastinum. Seen from behind. |
[edit] References
- ^ p132 Clinically Oriented Anatomy, 5th edition. Moore and Dalley.
[edit] External links
- Photo of dissection at kenyon.edu
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