MH 172 Cervix

Cervix

The cervix is the terminal, cylindrical region of the uterus that opens into the vagina. Its structure differs from the body and fundus of the uterus.

• Mucosa - unlike the rest of the uterus, it is not lost during menstruation.
  • Endocervix - forms the wall of the cervical canal.
    • Simple Columnar Epithelium - mostly mucus-secreting cells continuous with the lining of the body of the uterus.
    • Cervical Glands - branched glands of mucus secreting cells located in the lamina propria.
  • Ectocervix (or exocervix) - part of the cervix that protrudes in the vagina (portio vaginalis) and contains the opening of the uterus (external os).
    • Stratified Squamous Non-Keratinized Epithelium - continuous with the lining of the vagina.
      • Estrogen promotes the storage of glycogen in the middle and upper layers of the epithelium.
    • Cervical Glands - relatively few glands are found and are similar to those in the endocervix.
  • Transformation Zone - abrupt junction between the mucus-secreting columnar epithelium of the endocervix and the squamous epithelium of the ectocervix.
  • Nabothian Cysts - develop as stratified squamous epithelium grows over mucus-secreting simple columnar epithelium and entraps large amounts of mucus.
• Cervical Wall - composed of dense connective tissue rich in both collagen and elastic fibers. Unlike the rest of the uterus, it contains little smooth muscle.