SUPERFICIAL SQUAMOUS CELLS: These cells are derived  from  mature squamous epithelium which has developed to full thickness under the influence of oestrogen. They appear as large polygonal squames with transparent cytoplasm and angular borders . Folding is rare. They measure 45-50 u in  diameter. The nuclei are small condensed and pyknotic with no visible nuclear structure and do not exceed 5u . Karyorrhexis  is sometimes seen . The cytoplasm stains  pink  or  orange with occasional effete cells staining blue.