What is the Difference Between Parietal and Visceral Pleura?

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The pleura is a thin membrane that lines the inner surface of the thoracic cavity and covers the lungs. It can be divided into two layers: the parietal pleura and the visceral pleura.

Parietal Pleura:

  • Attaches to the chest wall
  • Covers the internal surface of the thoracic cavity
  • Thicker than the visceral pleura
  • Can be subdivided into four parts: mediastinal, costal, diaphragmatic, and cervical pleura
  • Receives blood supply from the intercostal arteries
  • Innervated by the intercostal nerve for the costal and cervical portions, and the phrenic nerve for the diaphragmatic portion. The parietal pleura is the only portion of the pleura that can sense pain

Visceral Pleura:

  • Covers the lungs, blood vessels, nerves, and bronchi
  • Extends into the interlobar fissures of the lungs
  • Continuous with the parietal pleura at the hilum of each lung
  • Receives blood supply from the bronchial circulation

The space between the parietal and visceral pleura is called the pleural cavity, which contains a small volume of serous fluid that lubricates the surfaces of the pleurae and produces surface tension, pulling the parietal and visceral pleura together.

Comparative Table: Parietal vs Visceral Pleura

Here is a table summarizing the differences between the parietal and visceral pleura:

Feature Parietal Pleura Visceral Pleura
Location Covers the internal surfaces of the thoracic cavity, including the ribs, diaphragm, and mediastinum Covers the outer surface of the lungs and extends into the interlobar fissures
Thickness Thicker than the visceral pleura More delicate and thinner than the parietal pleura
Lining Lines the inside of the chest wall, ribs, and diaphragm Lines the surface of the lungs
Continuity Continuous with the visceral pleura at the hilum of each lung Continuous with the parietal pleura at the hilum of each lung
Function Protection, respiration, and maintenance of negative pressure within the pleural cavity Lubrication of the surfaces of the pleurae, allowing them to slide over each other, and production of surface tension to pull the parietal and visceral pleura together

The parietal and visceral pleura are both serous membranes that line the lungs and thoracic cavity, permitting efficient and effortless respiration. They are continuous with each other at the hilum of each lung and form the boundaries of the pleural cavity, which contains a small amount of serous fluid.