# Oviduct (Uterine Tube) Histology > Oviduct histology for MBBS Anatomy: ciliated and peg cells, complex mucosal folds of ampulla, two muscle layers, ciliary transport, ectopic pregnancy and PID. - Canonical URL: https://prepelephant.com/topics/mbbs/anatomy/oviduct-histology - Exam / course: MBBS · Subject: Anatomy - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Oviduct (Uterine Tube) Histology", PrepElephant, https://prepelephant.com/topics/mbbs/anatomy/oviduct-histology ## Direct answer Ciliated cells sweep the ovum toward the uterus while narrow peg (secretory) cells bathe it in nutritive fluid — two populations, both simple columnar, both oestrogen-responsive, their proportions shifting along the tube and the cycle. The mucosa is thrown into delicate branching folds, tallest and most labyrinthine in the ampulla (the usual site of fertilisation and, when transport fails, of ectopic pregnancy), simpler in the narrow isthmus; beneath are an inner circular and outer longitudinal smooth-muscle coat (peristaltic assistance) and an outer serosa from the broad ligament's peritoneum. Cilia plus peristalsis plus secretion is a three-part conveyor, which is why anything that damages cilia — pelvic inflammatory disease above all — doubles the risk of tubal pregnancy. ## What you must remember - **Segment order and calibre:** intramural (in the uterine wall, narrowest lumen), isthmus, ampulla (about two-thirds of the tube's length, widest, most folded), infundibulum with fimbriae — examiners ask the order from uterus outward. - **Epithelium:** simple columnar with ciliated cells and non-ciliated peg cells, plus occasional basal cells; the ciliated fraction is greatest at the fimbriated end, where ovum pickup happens. - **Folds, not villi:** the mucosa forms complex primary, secondary and tertiary folds with a cellular lamina propria — the ampulla's folds nearly fill the lumen, a stark contrast to the isthmus's low ridges. - **Muscle:** inner circular and outer longitudinal smooth muscle, interlacing rather than cleanly layered; peristalsis moves the ovum with its cumulus mass toward the uterus over three to four days. - **Serosa and vasculature:** peritoneal covering of the broad ligament's upper margin (mesosalpinx), with anastomosing ovarian and uterine arterial supplies in the mesentery of the tube. - **Hormonal choreography:** oestrogen drives ciliogenesis and peak secretory activity before ovulation; progesterone later reduces ciliary height and increases secretion — the histology of the cycle's luteal phase. - **Clinical core:** the ampulla hosts the largest share of ectopic pregnancies; Chlamydia trachomatis pelvic inflammatory disease destroys cilia and narrows the lumen, and a tubal ligation that fails often does so through a fistulous end. ## Why the ectopic implants in the ampulla Transport is a race the zygote usually loses — and must lose. Fertilisation occurs in the ampullary lumen within hours of ovulation; the embryo divides slowly as cilia and peristalsis walk it toward the isthmus, whose narrower lumen and firmer muscle delay it further, so it reaches the uterine cavity at about the blastocyst stage, roughly three to four days later, when the endometrium is receptive. Damage the conveyor — chlamydial salpingitis with ciliary loss, post-infectious adhesions binding the folds together, endometriosis, or previous surgery — and the delayed embryo reaches implantation competence while still inside the tube wall, most often the ampulla, and invades the muscularis as it would the decidua. Histopathology confirms the diagnosis: chorionic villi and trophoblast within the tubal wall or lumen, often with haematosalpinx. The clinical anatomy explains the classic triad — amenorrhoea, pain, and bleeding — and the catastrophe: the tube's thin muscle and rich vasculature rupture around six to eight weeks, with intraperitoneal haemorrhage. Salpingostomy (for unruptured, conservation-minded cases) or salpingectomy removes the lesion; the contralateral tube's histology, assessed indirectly by patency tests, predicts the next pregnancy's risk. ## Where students slip The commonest error is describing tubal mucosa as villi — they are permanent folds of the whole mucosa, not epithelial projections, and using the word reveals memorisation without the slide. The second is the peg cell's identity: it is a secretory cell with expanded apical cytoplasm, not a worn-out ciliated cell, though the two are functionally paired. The third is forgetting the muscle coat entirely because the folds dominate the microscope field; the viva answer "how does the ovum travel" needs both — ciliary current and peristaltic wave — plus a mention that the fimbriae execute the initial pickup by sweeping over the ovarian surface at ovulation. ## Frequently asked questions ### Which cells line the uterine tube and what do they do? Simple columnar ciliated cells that propel the ovum toward the uterus and peg (secretory) cells that provide nutritive secretion, both under oestrogen influence. ### Why is the ampulla the commonest site of ectopic pregnancy? It is where fertilisation occurs and where damaged cilia or adhesions delay transport most, allowing the embryo to implant before reaching the uterus. ### How do the mucosal folds differ along the tube? The ampulla has tall, complex branching folds that nearly occlude its lumen, while the isthmus has low, simple ridges around a narrow channel. ### What effect does pelvic inflammatory disease have on tubal histology? Chlamydial and gonococcal infection destroys ciliated epithelium and fibroses the folds, impairing transport and raising ectopic pregnancy and infertility risk. ### What moves the ovum through the tube toward the uterus? Coordinated ciliary beating plus smooth-muscle peristalsis (inner circular, outer longitudinal coats), a journey of roughly three to four days to the cavity.