3.4. Nerve Supply of the Pleura
Parietal Pleural Nerves
The nerve supplies of the parietal and visceral pleural layers are different. However, both layers have only sensory fibres and no motor fibres, so the pleural layers cannot, for example, contract on their own. The parietal pleural layer is much more sensitive than the visceral pleural layer, and you will find that this is also the case with the sac surrounding the heart (the pericardium - see Section 7).
The parietal pleura is sensitive to pain, temperature, touch and pressure. It is supplied by:
- The intercostal nerves (T1 - T11) - unsurprisingly, these supply the costal and cervical pleurae as they travel with the ribs. The intercostal nerves also supply the peripheral parts of the diaphragmatic pleura.
- The phrenic nerve - supplies the mediastinal pleura and the central diaphragmatic pleura. In Section 7, you will see that this is expected because the phrenic nerve runs through the middle mediastinum (i.e. the heart and pericardium). At this stage, be aware that the diaphragm receives its motor nerve supply via the phrenic nerve, allowing it to contract.
Visceral Pleural Nerves
The visceral pleura is only sensitive to stretch. It is supplied by:
- General visceral sensory nerves (from the autonomic nervous system - see Section 6). These nerves are coming from the pulmonary plexuses, which lie on the primary bronchi and the pulmonary arteries (see Section 6.5.2.). In the context of this app, these nerves are not given specific names. (Note: 'general' refers to the fact that these nerves carry general info and do not carry 'special' info like taste or smell. 'Visceral' refers to the 'involuntary', 'unconscious' or 'autonomic' nature of these nerves. 'Sensory' refers to the type of info they carry.