PLEURA The pleura,which is a thin membrane that covers the inner surfaces of the thoracic cavity(胸腔)，consists of a layer of mesothelial cells(间皮细胞)supported by a network of connective and fibroelastic tissue.The visceral pleura (脏层胸膜)lines the lung,.whereas the parietal pleura(壁 层胸膜)lines the rib cage,diaphragm,and mediastinal structures. The closed space between the visceral and parietal pleura is referred to as the pleural space.The vascular supply of the parietal pleural surface is from the systemic circulation(体循环)，and it contains sensory nerves and lymphatics.By contrast,the visceral pleura is supplied with blood vessels from the pulmonary circulation(肺循环) and has no sensory nerves.第 一 部 分 The pleura, which is a thin membrane that covers the inner surfaces of the thoracic cavity（胸腔）, consists of a layer of mesothelial cells（间皮细胞） supported by a network of connective and fibroelastic tissue. The visceral pleura （脏层胸膜）lines the lung,whereas the parietal pleura（壁 层胸膜） lines the rib cage, diaphragm, and mediastinal structures. The closed space between the visceral and parietal pleura is referred to as the pleural space. The vascular supply of the parietal pleural surface is from the systemic circulation（体循环）, and it contains sensory nerves and lymphatics. By contrast, the visceral pleura is supplied with blood vessels from the pulmonary circulation（肺循环） and has no sensory nerves. PLEURA