I. What are the Components of the Male and Reproductive Tract?
For this section, weโll have to take a little trip back to basic sex-ed that you may have encountered back in the middle school days. We donโt mean to take you back to maybe one of the more โawkwarddddโ times in life, but it will help for sure when talking about these different anatomic concepts.
You donโt have to be an anatomical professor to do well in these concepts of the male and female reproductive tract, but having a good foundation in the basic reproductive anatomy should suffice your preparation for what the MCAT should cover!
II. Components and Function of the Male and Reproductive Tract
We believe the best way to understand the components of the male and female reproductive tract is to associate a general main function towards each structure in order to get a better connotation for each component.
A. Male Reproductive Tract
For us, the best way to organize the male reproductive tract is via 3 organelle categories: those for development, those with glandular secretions, and those involved with movement/storage of sperm. Take a look at the main diagram below!
We know this seems like a lot, but if you break down the organs into the different categories as mentioned above, itโll make things a whole lot simpler. Letโs start with the organelles which are important for maturation and development.
The seminiferous tubules are where spermatogenesis occurs which weโve covered in more detail in another article. There are 2 specific cells that are of importance to the seminiferous tubules are the Sertoli and the Leydig cells.
The Sertoli cells function as more of a supporting cell, nourishing the sperm cells as they undergo spermatogenesis while forming a tight protective barrier via tight junctions to prevent autoimmune attack, called the blood-testis barrier โ these cells are stimulated by FSH.
The Leydig cells function to produce and secrete testosterone via the stimulation by LH โ in addition to being the main hormone for stimulating male development, itโs also a crucial hormone in regards to the initiation of spermatogenesis.
After development in the seminiferous tubules, the sperm gain full motility in the epididymis and travel up the vas deferens where theyโll remain in the structure called the ejaculatory duct until ejaculation โ these 2 structures comprise the โmovement/storageโ structures of the male reproductive tract
There are 2 main glandular structures that all secrete into the ejaculatory duct to give the sperm more nourishment as well as a more fluid characteristic: the seminal vesicles and the prostate gland.
The seminal vesicles will secrete fructose to further nourish the sperm cells while the prostate gland secretes a fluid which is rich in various substrates like prostate specific antigen and spermine which basically helps the sperm to maintain its motility and survival.
Finally, the bulbourethral glands donโt secrete into the ejaculatory ducts but rather the urethra โ the alkaline, glycoprotein rich fluid helps to clear the urethra of any remnants or debris so that the sperm cells have a clear path upon ejaculation while also neutralizing the acidity from urine.
B. Female Reproductive Tract
What you might notice when looking at the female reproductive tract is that there are some parallels and analogies you can make between this tract and the male reproductive tract. Letโs go ahead and look at a sample diagram of the female reproductive tract!
The ovaries are essentially the female homolog of the testes as these organs are responsible for the maturation of egg cells which will be released and uptaken by the fallopian tube!
As shown below in a more detailed diagram of the fallopian tubes and ovaries, the fallopian tubes actually have finger-like projections called fimbriae which have an important role upon a mature egg release from the ovary.
Interestingly enough, the eggs are released directly into the fallopian tube but rather are released into the abdominal cavity fluid surrounding the fallopian tube and ovaries. The fimbriae can then โuptakeโ the released eggs from the abdominal cavity fluid and internalize it in the fallopian tube.
The fallopian tubes lead directly into the uterus, which is the organ which will support an embryo should there be a successful pregnancy. The uterus is composed of 3 main layers from outer to inner: perimetrium, myometrium (the muscular layer), and the endometrium.
Finally, the vagina is essentially a canal-like organ which essentially acts as a bridge between the external and internal female genitalia. Donโt worry about knowing the external portion of the female genitalia โ what was covered above should suffice come test day.
III. Bridge/Overlap
If youโve read our other reproductive articles, then this bridge section may be a little bit of a review for you! Weโll go ahead and touch upon some of the major endocrine hormones which are involved in modulating some of the physiological components of the reproductive system!
I. Hormonal Influence on Reproductive Structures
We already mentioned that FSH and LH are responsible for stimulating the Sertoli and Leydig cells to stimulate spermatogenesis and testosterone production respectively, but what of that for the female reproductive tract?
FSH โ which is secreted by the anterior pituitary โ similarly also promotes egg development and maturation in the ovary.
However, LH has a more specific role especially during the menstrual cycle. Recall that the LH surge is the main trigger which drives ovulation, that is the release of an egg from the ovary .
IV. Wrap Up/Key Terms
Letโs take this time to wrap up & concisely summarize what we covered above in the article!
A. Male Reproductive Tract
The testes and the epididymis are the main male reproductive organs to discuss when referring to the organs involved in the maturation and development of sperm cells.
The testes contain Sertoli and Leydig cells which work to nourish and produce testosterone, respectively. The epididymis is where the sperm cells gain motility where they then move into the vas deferens to eventually be housed in the ejaculatory duct.
The seminal vesicles and prostate gland secrete fluid directly into the ejaculatory duct which include fructose (from the seminal vesicles) as well as an alkaline, motility promoting fluid (by the prostate gland).
The bulbourethral glands will also secrete an alkaline rich fluid directly into the urethra in order to clear it from debris and protect the sperm from the acidic environment.
B. Female Reproductive Tract
The ovaries of the female reproductive tract are the equivalent of the male testes as these are the main organs involved in oocyte development and maturation. During ovulation, the ovaries secrete a mature ovum which is then uptaken by the fimbriae of the fallopian tubes.
The fallopian tubes connect the ovaries to the uterus which is an organ which will house an embryo should there be a successful pregnancy. Finally, the vagina is a canal like organ which acts as the bridge between the internal and external female genitalia organs.
V. Practice
Take a look at these practice questions to see and solidify your understanding!
Sample Practice Question 1
Which of the following is the best female homolog to the vas deferens of the male reproductive tract?
A. Ovaries
B. Fallopian Tube
C. Uterus
D. Vagina
Ans. B
This makes sense because similar to how the vas deferens is the tube of the male reproductive tract which connects the sperm formed and released by the testes to the ejaculatory duct, the fallopian tube connects the eggs released from the ovaries to the uterus!
Sample Practice Question 2
A woman who comes in to see her gynecologists unfortunately hears the news that she may be infertile. When asked for the possible reason why, the gynecologist states that one of her female reproductive tract structures is dysfunctional as they cannot uptake a released egg. Which of the following structures is she most likely referring to?
A. Fimbriae
B. Ovary
C. Uterus
D. Vagina
Ans. A
Recall that the function of the fimbriae in the female reproductive tract is to uptake the released egg from the ovaries into the fallopian tube where it can be led down into the uterus for implantation.
However if this structure is dysfunctional, this can lead to the inability to uptake the egg and can possibly result in an ectopic pregnancy.