Chronic bronchitis can be a premalignant condition, which involves:
Ans. (a) Columnar to squamous(Ref: Robbins 9th/pg 679)Chronic bronchitis is an example of squamous metaplasia in which normal columnar epithelium of respiratory tract is replaced by squamous epithelium;
Columnar to squamous
Squamous to columnar
Squamous to cuboidal
Cuboidal to squamous
Respiration