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.
Noun. 1. columnar epithelial cell-an epithelial cell that is shaped like a column; some have cilia. columnar cell. epithelial cell-one of the closely packed cells forming the epithelium. spongioblast-any of various columnar epithelial cells in the central nervous system that develop into neuroglia.. columnar epithelial cell-an epithelial cell that is shaped like a column; some have cilia. columnar cell. epithelial cell-one of the closely packed cells forming the epithelium. spongioblast-any of various columnar epithelial cells in the central nervous system that develop into neuroglia.