Simple Epithelia
Simple squamous epithelia play an important role in regulating passage of molecules across their surfaces. Squamous cells are in the form of flattened plates and may be so thin as to be difficult to recognize. They line the vascular system (endothelium), abdominal, cardiac, and thoracic cavities (mesothelium) and are found in other locations e.g., Bowman's capsule of the kidney, alveoli of the lung.