Female - Ampulla of Uterine Tube

1. Overview

The ampulla of the uterine tube is the widest and longest section of the fallopian tube (uterine tube). It plays a critical role in the transport of the ovum and is the most common site of fertilization in the female reproductive system. This segment facilitates the meeting of the oocyte and sperm, making it essential for successful conception and early embryonic development.

2. Location

The ampulla is located:

• Between the infundibulum (with fimbriae) and the isthmus of the uterine tube

• Extends medially from the ovary toward the uterus

• Suspended within the mesosalpinx, a portion of the broad ligament

It lies in close proximity to the ovary, allowing the fimbriae of the infundibulum to capture the ovum and deliver it into the ampulla for potential fertilization.

3. Structure

The ampulla features specialized histological adaptations for fertilization:

• Wall layers:

  • Mucosa: Highly folded with a branching lumen; lined by ciliated columnar epithelium and secretory peg cells

  • Muscularis: Two smooth muscle layers (inner circular, outer longitudinal) to promote peristalsis

  • Serosa: Outer peritoneal covering derived from the mesosalpinx

• Ciliated cells: Propel the ovum toward the uterus

• Secretory cells: Provide nutrients and facilitate sperm capacitation

4. Function

The primary functions of the ampulla include:

• Fertilization site: Provides an optimal environment for sperm-egg fusion

• Ovum transport: Facilitates movement of the oocyte from the infundibulum to the isthmus

• Sperm support: Secretes factors that enhance sperm survival and motility

• Early embryo support: Offers a nutritive environment for the zygote before it reaches the uterus

5. Physiological Role(s)

The ampulla plays crucial physiological roles in reproduction:

• Gamete interaction: Brings together sperm and oocyte in a favorable biochemical and mechanical environment

• Sperm capacitation and acrosome reaction: Secretions aid in sperm maturation necessary for fertilization

• Timing coordination: Ensures that ovum transport and endometrial receptivity are synchronized for implantation

• Selective transport: Only healthy sperm and viable embryos are allowed to pass through effectively

6. Clinical Significance

Ectopic Pregnancy

The ampulla is the most common site (over 70%) of ectopic pregnancies. When the fertilized ovum implants in the ampullary wall instead of the uterus:

• Early symptoms include abdominal pain and vaginal bleeding

• Rupture can lead to life-threatening hemorrhage

• Treatment includes methotrexate or surgical removal

Tubal Blockage and Infertility

Scarring or obstruction in the ampulla (often from pelvic inflammatory disease or endometriosis) can prevent:

• Ovum transport

• Sperm access

• Successful fertilization

This is a common cause of tubal factor infertility and may be evaluated via hysterosalpingography or laparoscopy.

Salpingitis

Inflammation of the uterine tube, including the ampulla, can lead to:

• Tubal scarring

• Hydrosalpinx (fluid-filled, dilated tube)

• Chronic pelvic pain and infertility

Usually caused by ascending infections such as Chlamydia trachomatis or Neisseria gonorrhoeae.

Surgical Considerations

In tubal ligation, the ampulla is preserved or divided depending on the method. In fertility-preserving surgeries (e.g., salpingostomy), the ampulla is targeted to remove ectopic tissue while maintaining reproductive function.

Assisted Reproductive Technologies (ART)

When the ampulla is damaged or absent, techniques such as in vitro fertilization (IVF) bypass the fallopian tubes by fertilizing oocytes outside the body and transferring embryos directly into the uterus.