The fallopian tubes and vasa deferentia--the plural form of vas deferens--are reproductive ducts in females and males, respectively. As such, both are involved in the process of reproduction---or the union of egg and sperm to produce a new organism. Both structurally and functionally, the ducts have some similarities.
Significance
In the female, explains Dr. Lauralee Sherwood in her book "Human Anatomy," a pair of ovaries sits slightly superior and to each side of the uterus. A pair of fallopian tubes, one on each side, leads from the ovary to the horn of the uterus. Ripened eggs ovulated each month travel through the fallopian tubes to the uterus. Similarly, the male gonads, or testes, are each attached to a vas deferens, through which mature sperm travel on their way out of the male body.
Function
Unlike many other reproductive ducts, the fallopian tubes and vasa deferentia are purely conductive. They don't participate in nurturing or maturing sperm cells, nor are they the site of egg maturation or egg implantation. There is one small difference between the two sets of ducts: The vasa deferentia actually attach to the testes, while the fallopian tubes simply end near the ovaries, notes Dr. Gary Thibodeau in his book "Anatomy and Physiology." However, in general, the function of the ducts is nearly the same.
Time Frame
Fallopian tubes and vasa deferentia develop at very similar points during fetal growth. Around 6 weeks of gestational age, explains Dr. Miriam Stoppard in her book "Conception, Pregnancy and Birth," the male testes begin producing testosterone. This causes the ducts that will become the vasa deferentia to begin developing further, while the ducts that might have become the fallopian tubes regress. In females, around the same time, the lack of testosterone causes the opposite effect.
Misconceptions
Unlike many of the other reproductive organs, which develop from embryonically identical tissue, one major difference between the vasa deferentia and fallopian tubes is that they don't come from the same set of embryonic cells. The same gonadal cells in an early embryo that become testes in a boy become ovaries in a girl, notes Dr. Sherwood. The same cells that become part of the penis in a boy become part of the clitoris in a girl. Although these similarities extend to the vast majority of the reproductive organs, the vasa deferentia and fallopian tubes are exceptions.
Expert Insight
One final important similarity between the fallopian tubes and vasa deferentia is that they can both lead to infertility, if obstructed. Pelvic inflammatory disease, endometriosis, and other processes can cause obstruction of the fallopian tubes, notes Dr. Stoppard, leading to female infertility and inability of the egg to reach the uterus. Similarly, if one or both vasa deferentia are obstructed, the sperm won't be able to reach the urethra, and won't be present in ejaculate, leading to male infertility.
References
- "Human Physiology"; Lauralee Sherwood, Ph.D.; 2004
- "Anatomy and Physiology"; Gary Thibodeau, Ph.D.; 2007
