Members of the DEWS Definition and Classification. Subcommittee developed a contemporary definition of dry eye disease and a three-. part classification system based on etiology, causative mechanisms and disease. severity.
Metaplasia. Definition: Metaplasia is the reversible replacement of one differentiated cell type with another differentiated cell type. Metaplasia causes precursor cells to change their cell fate, and do not change existing differentiated cells.he most common epithelial metaplasia is columnar to squamous (squamous metaplasia), as occurs in the respiratory tract in response to chronic irritation.
A pseudostratified columnar epithelium is a special type of simple epithelium that consists of a falsely-stratified single layer of epithelial cells resting on a basement membrane. Many, if not most, of the cells, are columnar. Ciliated pseudostratified columnar epithelium (Respiratory Epithelium) lines the upper respiratory tract. 2  Nonciliated pseudostratified columnar epithelium lines the epididymis of the male reproductive system.