The cervix is covered by the epithelium which is made of a thin layer of cells. Epithelial cells are either squamous or columnar (also called glandular cells). Squamous cells are flat and scaly, while columnar cells appear, as indicated by their name, column-like. Having regular Pap smears is imperative to detect early changes to the cervical cells which may lead to cervical cancer; however, you should know that the majority of abnormal Pap smears are due to inflammation or infection.
Understanding Cervical Changes: What Is The Cervix; National Institute of Cancer; http://www.cancer.gov/cancertopics/understandingcervicalchanges/page2; accessed 04/18/09.