Fallopian Tube Show
The fallopian tubes, also known as uterine tubes, oviducts[1] or salpinges (singular salpinx), are paired tubes in the human female that stretch from the uterus to the ovaries. The fallopian tubes are part of the female reproductive system. In other mammals they are only called oviducts.[2] Each tube is a muscular hollow organ[3] that is on average between 10 and 14 cm in length, with an external diameter of 1 cm.[4] It has four described parts: the intramural part, isthmus, ampulla, and infundibulum with associated fimbriae. Each tube has two openings a proximal opening nearest and opening to the uterus, and a distal opening furthest and opening to the abdomen. The fallopian tubes are held in place by the mesosalpinx a part of the broad ligament mesentery that wraps around the tubes. Another part of the broad ligament, the mesovarium suspends the ovaries in place.[5] An egg cell is transported from an ovary to a fallopian tube where it may be fertilized in the ampulla of the tube. The fallopian tubes are lined with simple columnar epithelium with hairlike extensions called cilia which move the fertilized egg (zygote) along the tube. On its journey to the uterus the zygote undergoes cell divisions that changes it to a blastocyst or early embryo, in readiness for implantation. Almost a third of cases of infertility are caused by fallopian tube pathologies. These include inflammation, and tubal obstructions. A number of tubal pathologies cause damage to the cilia of the tube which can impede movement of the sperm or egg.[6] The name comes from the Italian Catholic priest and anatomist Gabriele Falloppio, for whom other anatomical structures are also named. Structure[edit]Diagram showing the fimbriae of the fallopian tube infundibulum next to ovary Each fallopian tube leaves the uterus at an opening at the uterine horns known as the proximal tubal opening or proximal ostium.[7] The tubes have an average length of 10–14 centimeters (3.9–5.5 in)[4] that includes the intramural part of the tube. The tubes extend to near the ovaries where they open into the abdomen at the distal tubal openings. In other mammals the fallopian tube is called the oviduct which may also be used in reference to the fallopian tube in the human.[8][9] The fallopian tubes are held in place by the mesosalpinx a part of the broad ligament mesentery that wraps around the tubes. Another part of the broad ligament, the mesovarium suspends the ovaries in place.[5] Parts[edit]Each tube is composed of four parts: from inside the proximal tubal opening the intramural or interstitial part, that links to the narrow isthmus, the isthmus connects to the larger ampulla, which connects with the infundibulum and its associated fimbriae that opens into the peritoneal cavity from the distal tubal opening. Intramural part[edit]The intramural part or interstitial part of the fallopian tube lies in the myometrium, the muscular wall of the uterus. This is the narrowest part of the tube that crosses the uterus wall to connect with the isthmus. The intramural part is 0.7 mm wide and 1 cm long.[10] Isthmus[edit]The narrow isthmus links the tube to the uterus, and connects to the ampulla. The isthmus is a rounded, and firm muscular part of the tube. The isthmus is 1–5 mm wide, and 3 cm long.[10] The isthmus contains a large number of secretory cells.[8] Ampulla[edit]The ampulla is the major part of the fallopian tube. The ampulla is the widest part of the tube with a maximal luminal diameter of 1 cm, and a length of 5 cm. It curves over the ovary, and is the primary site of fertilization.[10] The ampulla contains a large number of ciliated epithelial cells.[8] It is thin walled with a much folded luminal surface, and opens into the infundibulum.[10] Infundibulum[edit]The infundibulum opens into the abdomen at the distal tubal opening and rests above the ovary. Most cells here are ciliated epithelial cells.[8] The opening is surrounded by fimbriae, which help in the collection of the oocyte after ovulation.[4] The fimbriae (singular fimbria) is a fringe of tissue around the distal tubal opening, oriented towards the ovary. Of all fimbriae, one fimbria known as the ovarian fimbria is long enough to reach the ovary.[11][12] An ovary is not directly connected to its adjacent fallopian tube. When ovulation is about to occur, the sex hormones activate the fimbriae, causing them to swell with blood and hit the ovary in a gentle, sweeping motion. An oocyte is released from the ovary into the peritoneal cavity and the cilia of the fimbriae sweep the ovum into the fallopian tube. Microanatomy[edit]Cross-section of fallopian tube, stained and viewed under microscope When viewed under the microscope, the fallopian tube has four to five layers (depending on the classification system used). From outer to inner, these are the serosa, subserosa, muscularis, submucosa and innermost mucosa with lamina propria, and epithelium. The serosa is derived from the visceral peritoneum. The subserosa is composed of loose adventitious tissue, blood vessels, lymphatics. The muscularis consist of outer longitudinal and inner circular smooth muscle coats. This layer is responsible for the rhythmic contraction, called peristalsis, of the fallopian tubes.[12] The histological features of tube vary along its length. The mucosa of the ampulla contains an extensive array of complex folds, whereas the relatively narrow isthmus has a thick muscular coat and simple mucosal folds.[12] The innermost layer of the tube is composed of a single layer of ciliated columnar epithelium. The ciliated columnar cells are most numerous in the infundibulum and ampulla. Estrogen increases the formation of cilia on these cells. Between the ciliated cells are peg cells, which contain apical granules and produce fluid. This fluid contains nutrients for spermatozoa, oocytes, and zygotes. The secretions also promote capacitation of the sperm by removing glycoproteins and other molecules from the plasma membrane of the sperm. Progesterone increases the number of peg cells, while estrogen increases their height and secretory activity. Fluid flows through the tubes toward the ovaries, the opposite direction to the action of the cilia. Development[edit]Stages of development of the Müllerian ducts (paramesonephric ducts) and their normal and abnormal development. Embryos develop a genital ridge that forms at their tail end and eventually forms the basis for the urinary system and reproductive tracts. Either side and to the front of this tract, around the sixth week develops a duct called the paramesonephric duct, also called the Müllerian duct.[13] A second duct, the mesonephric duct, develops adjacent to this. Both ducts become longer over the next two weeks, and the paramesonephric ducts around the eighth week cross to meet in the midline and fuse.[13] One duct then regresses, with this depending on whether the embryo is genetically female or male. In females, the paramesonephric duct remains, and eventually forms the female reproductive tract.[13] The portions of the paramesonephric duct which are more cranial—that is, further from the tail-end, end up forming the fallopian tubes.[13] In males, because of the presence of the Y sex chromosome, anti-Müllerian hormone is produced. This leads to the degeneration of the paramesonephric duct.[13] As the uterus develops, the part of the fallopian tubes closer to the uterus, the ampulla, becomes larger. Extensions from the fallopian tubes, the fimbriae, develop over time. Apart from the presence of sex chromosomes, specific genes associated with the development of the fallopian tubes include the Wnt and Hox groups of genes, Lim1, Pax2, and Emx2.[13] Embryos have two pairs of ducts that will let gametes out of the body when they are adults; one pair (the Müllerian ducts) develops in females into the fallopian tubes, uterus, and vagina, while the other pair (the Wolffian ducts) develops in males into the epididymis and vas deferens. The homologous organ in the male is the appendix testis.[14] Function[edit]Fertilization[edit]After ovulation, the egg (oocyte) passes from the ovary (left) through the fallopian tube to the uterus (right). The fallopian tube allows the passage of an egg from the ovary to the uterus. When an oocyte is developing in an ovary, it is surrounded by a spherical collection of cells known as an ovarian follicle. Just before ovulation, the primary oocyte completes meiosis I to form the first polar body and a secondary oocyte which is arrested in metaphase of meiosis II. At the time of ovulation in the menstrual cycle, the secondary oocyte is released from the ovary. The follicle and the ovary's wall rupture, allowing the secondary oocyte to escape. The secondary oocyte is caught by the fimbriated end of the fallopian tube and travels to the ampulla. Here, the egg is able to become fertilized with sperm. The ampulla is typically where the sperm are met and fertilization occurs; meiosis II is promptly completed. After fertilization, the ovum is now called a zygote and travels toward the uterus with the aid of the hairlike cilia and the activity of the muscle of the fallopian tube. The early embryo requires critical development in the fallopian tube.[8] After about five days, the new embryo enters the uterine cavity and, on about the sixth day, implants on the wall of the uterus. The release of an oocyte does not alternate between the two ovaries and seems to be random. After removal of an ovary, the remaining one produces an egg every month.[15] Clinical significance[edit]Almost a third of cases of infertility are caused by fallopian tube pathologies. These include inflammation, and tubal obstructions. A number of tubal pathologies cause damage to the cilia of the tube which can impede movement of the sperm or egg. A number of sexually transmitted infections can lead to infertility.[6] Inflammation[edit]Salpingitis is inflammation of the fallopian tubes and may be found alone, or with other pelvic inflammatory diseases (PIDs). A thickening of the fallopian tube at its narrow isthmus portion, due to inflammation, is known as salpingitis isthmica nodosa. Like another PID endometriosis, it may lead to fallopian tube obstruction. Fallopian tube obstruction may be a cause of infertility or ectopic pregnancy.[16] Blockage or narrowing[edit]If a blocked fallopian tube has affected fertility, its repair where possible may increase the chances of becoming pregnant.[17] Tubal obstruction can be proximal, distal or mid-segmental.Tubal obstruction is a major cause of infertility but full testing of tubal functions is not possible. However, the testing of patency – whether or not the tubes are open can be carried out using hysterosalpingography, laparoscopy and dye, or hystero contrast sonography (HyCoSy). During surgery, the condition of the tubes may be inspected and a dye such as methylene blue can be injected into the uterus and shown to pass through the tubes when the cervix is occluded. As tubal disease is often related to Chlamydia infection, testing for Chlamydia antibodies has become a cost-effective screening device for tubal pathology.[18] Implantation[edit]Occasionally the embryo implants outside of the uterus, creating an ectopic pregnancy. Most ectopic pregnancies occur in the fallopian tube, and are commonly known as tubal pregnancies.[19] Surgery[edit]Example and location of some surgical procedures performed on the fallopian tubes The surgical removal of a fallopian tube is called a salpingectomy. To remove both tubes is a bilateral salpingectomy. An operation that combines the removal of a fallopian tube with the removal of at least one ovary is a salpingo-oophorectomy. An operation to remove a fallopian tube obstruction is called a tuboplasty. A surgical procedure to permanently prevent conception is tubal ligation. Cancer[edit]Fallopian tube cancer, which typically arises from the epithelial lining of the fallopian tube, has historically been considered to be a very rare malignancy. Evidence suggests it probably represents a significant portion of what has previously been classified as ovarian cancer, as much as 80 per cent. These are classed as serous carcinomas, and are usually located in the fimbriated distal tube.[20] Other[edit]In rare cases a fallopian tube may prolapse into the vaginal canal following a hysterectomy. The swollen fimbriae can have the appearance of an adenocarcinoma.[21] History[edit]The fallopian tubes are named after the 16th-century Italian anatomist Gabriele Falloppio, the first person to provide a detailed description of the tubes.[22][13] He thought they resembled trumpets, tube in Italian, which was misunderstood and became the English "tube".[23] Though the name Fallopian tube is eponymous, it is often spelt with a lower case f from the assumption that the adjective fallopian has been absorbed into modern English as the de facto name for the structure. Merriam-Webster dictionary for example lists fallopian tube, often spelt Fallopian tube.[24] Additional images[edit]
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Which tissue would line the fallopian tubes?The fallopian tube (FT) is composed of three layers, and the innermost mucosa is a simple columnar epithelium consisting of basal, ciliated, and secretory cells [1]. The ciliated cells can facilitate the transport of gametes and mucus secreted by mucosal epithelium [2,3].
What tissue makes up the uterine tubes?Histologically, the uterine tubes are composed of 3 layers—the mucosa, muscularis, and serosa. The 3 different cell types within the mucosa of the uterine tubes include the columnar ciliated epithelial cells (25%), secretory cells (60%), and narrow peg cells (< 10%).
Which tissue would line the uterine tubes and function as a conveyor belt to help move a fertilized egg towards the uterus?There are, on the surface of the fimbria, microscopic hairs called cilia, which constantly beat in the direction of the uterus at a fantastically rapid speed and create a kind of conveyor-belt effect for moving the egg into the tube and toward the uterus.
What type of epithelial cells line the uterine tubes?The mucosal lining is simple columnar epithelium, consisting of two cell types -- ciliated cells and secretory cells.
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Which tissue would line the uterine fallopian tubes?
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