Describe the structure and histology of the fallopian tubes.

The tubes are muscular structures of paramesonephric (Mullerian) duct origin, 7-12 cm long, ~1 cm in diameter (internal diameter only ~1 mm at the uterine entry).

Histology: mucosa lined by ciliated columnar epithelium (no glands); the circular muscle layer is thickest at the isthmus and thinnest at the infundibulum. Regions: interstitial, isthmus, ampulla, infundibulum (with fimbriae).

Clinical relevance. Tubal structure/ciliated epithelium underlies ovum transport; damage causes ectopic pregnancy and infertility.

More Detail

Fallopian tube structure and histology

The tubes transport the ovum and are the usual site of fertilisation - and of ectopic pregnancy.

Structure

• Paramesonephric (Mullerian) duct origin; 7-12 cm long, about 1 cm in diameter, with an internal diameter of only ~1 mm at the uterine entry.
• Regions (medial to lateral): interstitial (intramural), isthmus, ampulla (widest - usual site of fertilisation), and infundibulum with fimbriae.

Histology

• Mucosa lined by columnar epithelium, with ciliated cells (waft the ovum toward the uterus) and secretory cells; no glands.
• The circular muscle layer is thickest at the isthmus and thinnest at the infundibulum.

Clinical relevance

• The ampulla is the commonest site of ectopic pregnancy; tubal damage (PID) impairs ciliary/muscular transport, predisposing to ectopic and infertility.