oviduct

An oviduct, also called the fallopian tube in mammals, is a paired tubular structure that carries oocytes from the ovary to the uterus. In humans, the oviducts extend from the upper corners of the uterus toward the ovaries, where they connect to the peritoneal cavity near the fimbriae of the infundibulum. Each oviduct consists of four regions: the infundibulum (with fimbriae that help capture ovulated oocytes), the ampulla (the usual site of fertilization), the isthmus (a narrower section that transports the embryo toward the uterus), and the uterine or interstitial segment that opens into the uterine cavity.

Histology includes a ciliated and secretory epithelium lining a thick muscular wall. Ciliary beating and peristaltic contractions move gametes and embryos; tubal fluid provides nutrients and a suitable environment for fertilization and early development. Functionally, the oviduct captures the ovulated oocyte, promotes fertilization in the ampulla, and transports the resulting embryo to the uterus for implantation. Hormonal regulation influences its motility and secretory activity throughout the reproductive cycle.

Variation among vertebrates is notable: in birds and reptiles, the oviduct is longer and differentiated into regions dedicated to albumen secretion, shell membranes, and calcified shells, reflecting its role in eggs rather than post-ovulation fertilization.

Clinical relevance includes tubal infertility from blockages or damage, ectopic pregnancy that often occurs in the oviduct, and surgical methods such as tubal ligation or salpingectomy to interrupt function.

Developmentally, the oviduct arises from the Müllerian ducts (paramesonephric ducts) during embryogenesis and is supplied by ovarian and uterine arteries with autonomic innervation.