two thin membranes surround the lungs and are known as serous membrane.
two thin membranes surround the lungs and are known as serous membrane.
two thin membranes surround the lungs. what are these membranes known as?
serous membrane
the lungs are the largest organs in the lower respiratory tract. the lungs are suspended within the pleural cavity of the thorax. the pleurae are two thin membranes, one cell layer thick, which surround the lungs. the inner (visceral pleura) covers the lungs and the outer (parietal pleura) lines the inner surface of the chest wall. this membrane secretes a small amount of fluid, allowing the lungs to move freely within the pleural cavity while expanding and contracting during breathing. the lungs are divided into different lobes. the right lung is larger in size than the left, because of the heart's being situated to the left of the midline. the right lung has three lobes – upper, middle, and lower (or superior, middle and inferior), and the left lung has two – upper and lower (or superior and inferior), plus a small tongue-shaped portion of the upper lobe known as the lingula. each lobe is further divided up into segments called bronchopulmonary segments. each lung has a costal surface, which is adjacent to the ribcage; a diaphragmatic surface, which faces downward toward the diaphragm; and a mediastinal surface, which faces toward the center of the chest, and lies against the heart, great vessels, and the carina where the two mainstem bronchi branch off from the base of the trachea.
respiratory tract
electrostatic–pneumatic activation









































electrostatic–pneumatic activation is an actuation method for shaping thin membranes for mems and moems devices. this method benefits from operation at high speed and low power consumption. it can also cause large deflection on thin membranes. electrostatic-pneumatic mems devices usually consist of two membranes with a sealed cavity in between. one membrane calling actuator deflects into cavity by electrostatic pressure to compress air and increase air pressure. elevated pressure pushes the other membrane and cause dome shape. with direct electrostatic actuation on membrane, a concave shape is achieved.









































this method is used in mems deformable mirrors
electrostatic–pneumatic activation