Final answer:
The transformation zone is where the columnar epithelium of the cervix meets the squamous epithelium of the vagina, and it's a crucial area examined in Pap smears for signs of cervical cancer.
Step-by-step explanation:
The point at which the columnar epithelium of the cervix meets the squamous epithelium of the vagina is called the transformation zone. This area is of particular interest during a Papanicolaou test, commonly known as a Pap smear, as it is where abnormal cell growth indicative of potential cervical cancer can occur. During a Pap smear, a cytotechnologist examines this region after staining cells that have been collected from the cervical smear. One of the key indicators of infection, particularly human papillomavirus (HPV), in these cell samples is the presence of koilocytes. These cells have a distinctive appearance, including a hyperchromatic nucleus that stains darkly and a clear perinuclear halo.