Topography and anatomical segments
The oviduct has a specific spatial orientation. Its proximal end pierces the uterine wall and opens directly into the uterine cavity. The distal end faces the ovary: anatomically it is not fused with it (free), but functionally it is in close contact.
Outside of ovulation, the distal opening is closed due to the high tone of smooth muscle. If this opening opens pathologically, an unnatural communication forms between the oviduct lumen and the peritoneal cavity.
Morphologically, the tube is divided into four segments (from the ovary towards the uterus):
- Infundibulum (Infundibulum) — the distal end, provided with fimbriae along the edges for efficient oocyte capture.
- Ampulla (Ampulla) — the longest section of the organ, occupying about half of its length.
- Isthmus (Isthmus) — the narrowed segment located closer to the body of the uterus.
- Uterine part (Pars uterina) — the intramural section passing inside the lateral wall of the uterus.
Histological structure of the wall
In a cross-section of the organ, a complex-shaped lumen is clearly visible. This is due to the structure of the internal layers. The oviduct wall is formed by three classic coats:
1. Mucous membrane (Tunica mucosa) Forms massive, highly branched longitudinal folds that occupy most of the lumen. Lined with simple ciliated columnar epithelium, which includes two cell differons:
- Ciliated cells: bear cilia on their apical pole, the beating of which ensures fluid flow and the directed movement of the egg.
- Glandular (secretory) cells: produce a mucous secretion necessary for the trophism and protection of germ cells and the zygote.
Beneath the epithelial layer lies the lamina propria (Lamina propria), formed by loose connective tissue.
2. Muscular coat (Tunica muscularis) Forms the main thickness of the wall. Formed by smooth muscle tissue, the bundles of which are separated by thin connective tissue layers. Consists of two layers:
- Inner: circular-spiral.
- Outer: longitudinal.
3. Serous coat (Tunica serosa) The oviduct is covered by the peritoneum almost completely ( intraperitoneally), forming the mesosalpinx. Histologically, the coat is represented by mesothelium with underlying connective tissue.
Physiology and mechanisms of transport
The activity of the uterine tube is strictly synchronized with the phases of the woman's reproductive cycle:
- Capture mechanism. During ovulation, the blood vessels of the infundibulum actively fill with blood. As a result, the tissue swells, and the fimbriae tightly wrap around the ovary. At the same time, the tone of the infundibulum myocytes drops, leading to the temporary opening of the distal opening—the tube turns into a receptacle for the secondary oocyte.
- Transport function. The oviduct ensures the slow passive movement of the oocyte and developing embryo along with tubular fluid toward the uterine cavity. This process is driven by two factors: the rhythmic beating of epithelial cilia and peristaltic contractions of the muscular coat.
Clinical significance: ectopic pregnancy
Normally, embryo transport to the uterus takes 4–5 days. If transport function is impaired, the developing embryo cannot move in time and implants directly into the wall of the tube.
All layers of the tube are very richly vascularized. Such a rich blood supply allows the embryo to successfully attach and begin development, as trophic conditions permit. However, anatomically the oviduct wall is completely unsuited for full fetal development, so such a pathological (tubal) pregnancy usually ends in termination.
Briefly: answers to topical questions
What is the source of development of the uterine tube in embryogenesis?
The source of development of the uterine tube in embryogenesis is the paramesonephric (müllerian) ducts. During intrauterine development, the female reproductive tract is formed from these embryonic structures:
- Upper parts of the ducts — transform and give rise to the uterine tubes.
- Lower parts of the ducts — fuse together to form the uterus and vagina.
What are the sources of blood supply to the uterine tube?
The blood supply to the uterine tube is connected with the ovarian artery: the ovarian artery (a. ovarica) originates directly from the aorta or from the renal artery, passes within the thickness of the suspensory ligament of the ovary and gives off branches directly to the ovary and the uterine tube. Also, the ovarian artery forms a pronounced anastomosis with a branch of the uterine artery; the uterine artery is a visceral branch of the internal iliac artery, ascends along the lateral margin of the uterus, and anastomoses within the broad ligament with the ovarian artery.
To remember the segments of the uterine tube (from the ovary), use the acronym: Infundibulum, Ampulla, Isthmus, Uterine part.
Class and exam questions
In which part of the tube does fertilization occur?
The meeting of the spermatozoon and oocyte occurs in the ampulla of the tube, its longest section.
Which cells form the mucosal epithelium?
The mucosa is lined with simple ciliated columnar epithelium. It consists of ciliated cells (responsible for fluid flow) and secretory cells (producing protective and nutritive secretion).
How does the egg move toward the uterus?
Passive movement of the oocyte is ensured by the beating of epithelial cilia and peristaltic contractions of the muscular coat of the tube.
Why can an embryo develop in the tube during an ectopic pregnancy?
The tube wall is richly vascularized. Good blood supply creates favorable trophic conditions for initial implantation and early embryo development, although the organ is not adapted for carrying a fetus.
What else to study on this topic
- Cellular composition of the epithelium: ultrastructure of ciliated and secretory cells
- Hemodynamic changes in infundibulum vessels during ovulation
- Mechanisms of formation and composition of tubular fluid
- Features of the ratio of muscular coat layers in different parts of the tube
- Pathogenesis and outcomes of tubal ectopic pregnancy
Master the entire topic in the "Histology" course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Uterine tube" and another 3,485 pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 137 video lessons on the subject
Other topics in the "Female reproductive system" section
Free video lessons: histologyShort lessons with study notes — no registration required.
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.