What are Fallopian tubes?
The fallopian tubes are also known as uterine tube or oviducts. There are two fallopian tubes present in every female body which are 4 inches long narrow and 1cm wide, and they connect the ovaries to the uterus. The female eggs cell called the Ova are carried to the uterus from the ovaries for the process of fertilisation.
In case a woman may lose one of her fallopian tubes due to a biological abnormality, surgery or ectopic pregnancy, she can still remain healthy and reproductive. Loss of or tying of both fallopian tubes leads to sterilisation and hinders a woman from getting pregnant.
Where are Fallopian tubes located?
They are located in the lower abdominal or pelvic cavity of the female body. They are present bilaterally at the superior part of the uterine cavity.
A part of uterine tubes called the ampulla is where the female eggs get fertilised by the male sperm. The fertilised egg then moves to the womb or uterus where it remains until it is fully developed until birth.
Structure and Development
The anatomical structure of the fallopian tubes begins at the uterus as very narrow tubes and gradually widens when it reaches the ovaries. It consists of four parts from medial to lateral (Isthmus, ampulla, infundibulum and fimbriae)
The isthmus is the narrowest part of the fallopian tubes and has the thickest wall, and it is located near the uterus. From there the isthmus widens into the ampulla which carries on widening until it reaches the funnel-shaped infundibulum before ending into the ovaries. Finger-like projections called the fimbriae extend from the infundibulum to reach the surface of the ovaries.
The uterine tubes contain many of the same tissue layers as the womb. The outermost thin covering of the fallopian tubes, the serosa is composed of a membrane of simple squamous epithelial tissues which are supported by areolar connective tissue.
A fluid is secreted from the serosa which lubricates the uterine tubes to protect them from friction with neighbouring organs.
Deep to the serosa is a visceral tissue which forms the muscular layer and is responsible for the movement of these fallopian tubes. The mucosa which is the innermost layer of the fallopian tubes lines the hollow lumen and is made of ciliated columnar epithelial tissue.
The arterial supply of the fallopian tubes is from the branches of ovarian and uterine arteries, and the nerve supply is via both sympathetic and parasympathetic nerves. Sensory fibres run from thoracic T11-T12 segments and the lumbar L1 segment.
The lymphatic drainage of the fallopian tubes is via the iliac and lateral aortic nodes.
Function
The major function of uterine tubes is to transfer the ova from the ovaries to the uterus and play an active role in the process of fertilisation.
Before the ovulation, smooth muscles in the fimbriae produce slow contractions in response to the changing levels of female sex hormones.
These contractions make the fimbriae sweep the surface of the ovaries in anticipation of the release of ova. Once it is released, the fimbriae pick it up and carry the ovum to the infundibulum.
Then the ovum passes through the infundibulum, ampulla and isthmus towards the uterus due to the peristaltic movements of the cilia in the mucosal lining. Finally, the sperms deposited may enter the fallopian tubes from the uterus and fertilise the ovum as it travels to the womb.
Clinical significance
The fallopian tubes transport the female egg cell to the uterus from the ovary. They also help to move the male sperm cells to the egg and provide a suitable environment for fertilisation.
The secretions of the mucous membrane lining the uterine tubes not only help to transport the sperm and egg but also keep them alive. The secretions are composed of many vital nutrients such as calcium, sodium chloride, glucose, proteins, lactic acid and bicarbonates. The bicarbonates and lactic acid are critical to developing the egg after it has been fertilised. They also help the sperm to use oxygen to stay alive.
Fallopian tube Pain
Almost one-third of the women experience sharp pelvic pain which is unlike pain experienced during the menstrual cycle. If the sharp pain occurs on either side of the lower abdomen, it is due to abnormality or blockage of fallopian tubes.
Tubal factor infertility is a condition in which a woman’s fallopian tube gets blocked, and she is unable to get pregnant. It affects 40% of the women in America alone. The uterine tubes can get blocked due to several reasons such as:
- Pelvic inflammatory disease
- History of ruptured appendix
- Previous abdominal surgery.
- Previous ectopic pregnancy.
- History of abortion or miscarriage.
- History of sexually transmitted diseases such as chlamydia or gonorrhoea.
- Endometriosis which is a long-term condition where small fragments of the lining of the uterus are found outside the womb, mainly on the ovaries and fallopian tubes. This leads to painful shedding of these pieces which cause blockage of the fallopian tubes and extreme pain.
Both ultrasonography and hysterosalpingography can be used by doctors for diagnosing any uterine anomalies.
Fallopian Tube Removal
Women who do not want to have children or who are happy with the number of children they already have can have their fallopian tubes tied up. This prevents any chances of pregnancy by surgically cutting of the fallopian tubes and tying them. The woman then becomes sterile and can never have babies unless she decides to reverse the procedure and untie one or both of her fallopian tubes.
Some women may suffer from an ectopic pregnancy which puts their lives at risk. The tubal or ectopic pregnancy occurs when the fertilised egg remains in the fallopian tubes and does not travel to the uterus. They are treated by surgically removing the egg which terminates the pregnancy.
This is mostly common in women with a history of sexually transmitted diseases who have had multiple sexual partners in the past.
