méhnyak

Méhnyak, or cervix uteri, is the lower part of the uterus that opens into the vagina. It forms a gateway between the uterine cavity and the birth canal and plays a role in fertility, pregnancy, and protection against infection.

Anatomy and histology: The cervix consists of the endocervix (the cervical canal, lined by mucus-secreting simple columnar epithelium) and the ectocervix (the portion projecting into the vagina, lined by non-keratinized stratified squamous epithelium). The squamocolumnar junction marks the transition between these epithelia. The cervix contains an internal os, opening into the uterine cavity, and an external os, opening into the vagina. It receives blood from the uterine arteries, drains via uterine and vaginal venous plexuses, and lymphatics target the iliac and sacral nodes.

Function: Cervical mucus changes with the menstrual cycle to influence sperm movement; it is typically thinner around ovulation and thicker at other times. The cervix forms a mucus plug during pregnancy to help protect the uterus and remains closed until labor, when it gradually dilates.

Clinical relevance: The cervix is central to cervical cancer screening. Persistent human papillomavirus (HPV) infection can lead to cervical intraepithelial neoplasia (CIN) and cancer. Screening methods include cytology (Pap tests) and HPV testing; abnormal results may prompt colposcopy, biopsy, and treatment such as loop electrosurgical excision procedure (LEEP) or cone biopsy. Obstetric care may address cervical insufficiency or employ cerclage in selected cases. Benign conditions include cervicitis, nabothian cysts, and polyps.