Anatomy of the visceral pleura

The visceral pleura (VP) of the sheep, an animal with similar pleural anatomy to humans. The visceral pleura lies between the pleural space (PS) and the alveoli (Alv). It is approximately 20 to 80 µm thick and consists of a single mesothelial layer (M) and a subpleural connective tissue layer. The subpleural connective tissue layer contains both collagen and elastin as well as the bronchial arteries (A, which drain into pulmonary veins) and subpleural lymphatics (which do not connect to the pleural space). The bronchial microvessels and lymphatics are relatively far from the pleural space (20 to 50 µm versus 10 to 12 µm in the parietal pleura).