Reproductive Histology

In the male, the testes contain seminiferous tubules lined by germ cells and Sertoli cells. Sertoli cells (nursing cells) provide support and form the blood-testis barrier. Leydig cells, located in the interstitium, produce testosterone. Spermatozoa mature as they move from the basement membrane to the lumen through stages (spermatogonia, primary/secondary spermatocytes, spermatids). In the female, the ovary contains follicles at various stages: primordial, primary, secondary, and Graafian (mature). After ovulation, the follicle becomes the corpus luteum (secretes progesterone). The fallopian tubes (oviducts) feature a folded mucosa with ciliated cells to move the oocyte/embryo. The uterus has a thick muscular myometrium and a glandular endometrium. The endometrium undergoes cyclic changes: the proliferative phase (oestrogen-driven, straight glands) and the secretory phase (progesterone-driven, corkscrew glands). The cervix contains a transformation zone where simple columnar epithelium meets stratified squamous epithelium—a critical site for oncogenesis.

Spermatogenesis takes approximately 64-74 days. The blood-testis barrier (tight junctions between Sertoli cells) protects developing sperm from autoimmune attack. Oogenesis involves meiosis, which arrests in Prophase I at birth and Metaphase II at ovulation. Implantation in the uterus occurs in the secretory phase when the endometrium is thick and nutrient-rich. HCG, produced by the syncytiotrophoblast of the embryo, maintains the corpus luteum in early pregnancy. The cervix produces different types of mucus: thin and watery under oestrogen (to aid sperm passage) and thick under progesterone.

Cervical cancer typically arises at the transformation zone (detected via smear/PAP test). Endometriosis is the presence of endometrial glands and stroma outside the uterus. Polycystic Ovary Syndrome (PCOS) involves multiple follicular cysts and theca cell hyperplasia. Ectopic pregnancy often occurs in the fallopian tubes. Prostatic hyperplasia (BPH) occurs in the transition zone, while prostate cancer usually occurs in the peripheral zone. Histology is essential for grading these malignancies (e.g., Gleason score for prostate).

Cervical cytology (smear). Semen analysis. Ovarian/Prostate biopsy. Endometrial 'pipelle' biopsy for abnormal bleeding. Histology for PID (inflammatory infiltrate).

Not directly applicable to this basic-science topic; management ranges from hormonal therapy and IVF to surgical resection for malignancy.