Fallopian tube

A fallopian tube, also called uterine tube, is part of a woman's reproductive system. Typically, women have a set of two fallopian tubes. They are responsible for carrying the ova, or eggs, from the ovaries (female reproductive organs) to the uterus (organ that houses a developing baby). In pregnancy, the fallopian tubes aid in fertilization and then transport the fertilized egg, or zygote, to the uterus where it gets ready for implantation, or the process in which the zygote attaches to the lining of the uterus. A number of abnormalities, some of which can cause serious health issues, can afflict the fallopian tubes.

Background

The fallopian tube was named after Italian physician and surgeon Gabriele Falloppio, who studied anatomy, physiology, and pharmacology during the sixteenth century. He also studied the muscles, kidneys, vascular system, and female and male reproductive systems. He became somewhat of an expert on sexually transmitted infections, specifically syphilis. While Falloppio was credited with being the first person to describe the fallopian tubes, he did not document their function. The following century, Dutch scientist Reinier de Graaf became the first person to describe how the fallopian tubes worked in conjunction with the female reproductive system. He also documented several abnormalities associated with the fallopian tubes.

The fallopian tubes are located in the reproductive system in a woman's body. Each woman typically has a set of two uterine tubes that connect the ovaries to the uterus. When an ovary releases an egg, the fallopian tube helps guide the sperm toward the egg. Once the sperm enters the egg and fertilization occurs, the fallopian tube allows the zygote (fertilized egg) to travel through the tube to the uterus, where the zygote prepares to implant itself into the lining of the uterus and remain there until birth. Unfertilized eggs travel the same course but are flushed out of the system during a woman's menstrual period. The tubes have cilia, or hair-like projections, on the cells of their lining. The cilia help move the egg through the tube and to the uterus.

Each fallopian tube is about six to thirteen centimeters in length and about one centimeter in diameter. Three parts compose the uterine tube: isthmus, ampulla, and infundibulum. The isthmus is the thinnest part and is located closest to the uterus at a horned area called the cornua. The middle segment, the ampulla, widens in diameter and is the site of fertilization. The infundibulum is located the farthest from the uterus and has fimbriae, which are fringe-like tissues that help to grab the eggs released by the ovaries.

Each fallopian tube has three layers: mucosa, muscularis, and serosa. The mucosa is the inner layer and is composed of many folds known as plicae. The muscularis is the middle layer and is made of a smooth muscle that encases the mucosa. The outer layer is the serosa and is part of the visceral peritoneum, which covers various organs in the body.

Overview

Most women are born with two fallopian tubes. Sometimes medical conditions can cause a woman to lose one or even both of her uterine tubes. Several other abnormalities can afflict the fallopian tubes. Some of these include cancer; endometriosis; pelvic inflammatory disease; sexually transmitted infections such as chlamydia and gonorrhea; using intrauterine devices as birth control; a ruptured appendix; or the formation of tumors, fibroids, or scar tissue. These can cause severe infections, which can lead to blockages or scarring of the uterine tubes, affect fertility (a woman's ability to get or remain pregnant), and jeopardize a woman's life.

Endometriosis is a condition in which the body grows endometrium (the tissue lining of the uterus shed during the menstrual cycle) outside of the uterus. This condition can cause tissue to grow over the ovaries, uterine tubes, and pelvic cavity. When the tissue outside of the uterus breaks down during a woman's period, it has nowhere to go and builds up over time. This causes irritation and inflammation, which can be very painful. It also may cause scar tissue to form. The buildup of tissue can block the ovaries from releasing eggs, prevent the eggs from becoming fertilized, and block the fallopian tubes, thus affecting their function.

Other infections can cause the fallopian tubes to twist, bend, or narrow in diameter. This can lead to an ectopic pregnancy (also called a tubal pregnancy), in which the zygote gets stuck in the uterine tube and develops there or in another place outside of the uterus. Ectopic pregnancies are not viable and are usually terminated with surgery. They can be life threatening to a woman and can cause her to lose one or both of her fallopian tubes. This can affect a woman's ability to get pregnant and can lead to infertility.

Sometimes infections can cause the cilia not to work properly. Damaged cilia may be unable to move an egg through the fallopian tubes. This can lead to a blockage and result in an ectopic pregnancy. Scar tissue buildup can block the ovaries and uterine tubes. This can prevent the release of the egg, the fertilization of the egg, or the egg's ability to reach the uterus.

Women who do not want to become pregnant can opt to have a tubal ligation, also known as getting their "tubes tied." During a tubal ligation, also called female sterilization, a physician cuts and ties, or blocks, the fallopian tubes. This prevents the passage of an egg from the ovaries through the fallopian tubes to the uterus. Tubal ligations are usually permanent and can carry some health risks.

Bibliography

"Definition of Fallopian Tube." MedicineNet, 13 May 2016, www.medicinenet.com/script/main/art.asp?articlekey=3375. Accessed 3 Nov. 2016.

"Endometriosis and Fallopian Tube Problems." WebMD, 28 Oct. 2016, www.webmd.com/women/endometriosis/endometriosis-and-fallopian-tube-problems#1. Accessed 3 Nov. 2016.

"Female Infertility." Mayo Clinic, 16 July 2013, www.mayoclinic.org/diseases-conditions/female-infertility/basics/causes/con-20033618. Accessed 3 Nov. 2016.

Rebar, Robert W. "Problems with the Fallopian Tubes." Merck Manual Consumer Version, www.merckmanuals.com/home/women-s-health-issues/infertility/problems-with-the-fallopian-tubes. Accessed 3 Nov. 2016.

Schnatz, Rebecca Heuer, and Aurora M. Miranda. "Uterine Tube (Fallopian Tube) Anatomy." Medscape, 10 Dec. 2014, emedicine.medscape.com/article/1949193-overview. Accessed 3 Nov. 2016.

Tripathy, SN, editor. The Fallopian Tubes. Jaypee Brothers, 2013, pp. 1–13.

"Tubal Ligation and Tubal Implants." WebMD, 5 Aug. 2015, www.webmd.com/sex/birth-control/tubal-ligation-and-tubal-implants. Accessed 3 Nov. 2016.

"Uterine Tube (Fallopian Tube)." Healthline, 25 Mar. 2015, www.healthline.com/human-body-maps/fallopian-tubes. Accessed 3 Nov. 2016.

"What to Know about Ectopic Pregnancy." WebMD, 20 Sept. 2014, www.webmd.com/baby/guide/pregnancy-ectopic-pregnancy#1. Accessed 3 Nov. 2016.