Pseudostratified epithelium is a type of tissue that appears to be layered due to the varying heights of its cells, but all cells actually touch the basement membrane. This unique structure allows for efficient absorption and secretion, making it important in areas like the respiratory tract. This epithelium often contains cilia and goblet cells, which help to trap and move particles out of the airways. It is primarily found lining the trachea and bronchi, playing a crucial role in protecting the respiratory system from pathogens and debris.