Final answer:
The serous membrane that lines the thoracic cavity, mediastinum, and diaphragm is the parietal pleura. It is part of the pleura that consists of two layers, with the pleural cavity in between, and it serves to reduce friction around the lungs.
Step-by-step explanation:
The specific serous membrane that lines the walls of the thoracic cavity, the lateral surface of the mediastinum, and covers the superior surface of the diaphragm is known as the parietal pleura. This membrane is part of the pleura, which is the serous membrane surrounding the lungs. The pleurae consist of two layers: the visceral pleura, which covers the lungs, and the parietal pleura, which attaches to the thoracic wall, the mediastinum, and the diaphragm. Between these two layers is the pleural cavity, a fluid-filled space that reduces friction and facilitates smooth movement during respiration.
Serous membranes are composed of a mesodermally derived epithelium called the mesothelium, which is supported by an underlying layer of connective tissue. The secreted serous fluid provides lubrication to minimize abrasion and friction between the moving organs, such as the expansion and contraction of the lungs and the heartbeats. Thus, the parietal pleura plays a crucial role in protecting the lungs by forming a lubricated, friction-reducing sac around them.