Pleurae

• The pleurae refer to the serous membranes that line the lungs and thoracic cavity.
• The visceral pleura outlines the the lungs, whereas the parietal pleura lines the inner wall of the thoracic cavity
• The visceral and parietal pleura are continuous with each other at the hilum of the lung
• The pleural cavity is a potential space between the parietal and visceral pleura. It contains a small volume of serous fluid, which has two major functions.

  It lubricates the surfaces of the pleurae, allowing them to slide over each other. The serous fluid also produces a surface tension, pulling the parietal and visceral pleura together. This ensures that when the thorax expands, the lung also expands, filling with air.
• • The parietal pleura is sensitive to pressure, pain, and temperature. It produces a well localised pain, and is innervated by the phrenic and intercostal nerves.
  • The visceral pleura is not sensitive to pain, temperature or touch. Its sensory fibres only detect stretch. It also receives autonomic innervation from the pulmonary plexus (a network of nerves derived from the sympathetic trunk and vagus nerve).
• • The arterial supply of the parietal pleura is the intercostal arteries
  • The arterial supply of the visceral pleura is the bronchial arteries
• Pleural anatomy:

  A) Parietal pleura

  B) Visceral pleura

  C) Pleural cavity

  D) Hilum