Female Reproductive System

last authored: Allyson Opoku, Feb 2011
last reviewed: Sara McNorton, Feb 2011




 The female reproductive system is responsible for the processes of fertilization and birth in the female body. The main components of the system are the vagina, the cervix, the uterus, the ovaries and the fallopian tubes. The reproductive process begins once the penis enters the vagina, sending sperm up the cervix and into the uterus. Depending on which stage the woman is in her menstrual cycle, an ovum will be released from the ovary. It will travel through the fallopian tubes which then makes it capable to be fertilized by sperm. At that point, the zygote will continue travelling through the fallopian (uterine) tubes until implantation occurs in the uterus after approximately 6 days. After the general gestation period of 9 months (for homo sapiens), the cervix begins to dilate and the uterus contract in preparation of the birth of the fetus, which will leave through the vagina.





main article: menstrual cycle

Oogenesis, or formation of oocytes (eggs), is confined to prenatal development. Women are normally born with 2.5 million oocytes, but only about 400 mature and are involved in a woman's menstrual periods throughout life. Oocytes undergo meiosis. They are held in Prophase I, complete meiosis I at ovulation, and go through meiosis II at fertilization.


The menstrual cycle is an important process which helps regulate the female reproductive system. It consists of three major phases, the follicular phase, ovulation and the luteal phase. On a typical 28-day cycle , the follicular phase occurs from day 1 until day 13; on day 14, ovulation occurs; and from day 15 to day 28 the luteal phase occurs.


The follicular phase begins with increased levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) which are secreted from the pituitary gland. This increased expression of FSH and LH allow some selected ovarian follicles to grow and become a part of the menstrual cycle.  As the FSH and LH levels continue to rise, estrogen is released in higher amounts; which stimulates the uterine lining to thicken and stimulates the cervix to develop a mucus layer which aids sperm travelling up the cervix to fertilize an ovum.


At ovulation, LH is responsible for stimulating the release of the ovum from the follicle. The remaining follicle is called the corpus luteum which grows for a short while. The ovum continues along the fallopian tubes to the uterus. At this point, if it is not fertilized by any sperm, the egg and the wall of the uterus will begin to breakdown, which will lead to menstruation. Eventually, the corpus luteum degenerates into the corpus albicans. If the ovum is fertilized, it will be implanted within the uterine lining and continue to grow during pregnancy. Also, estrogen levels are at its highest point, causing FSH and LH levels to drop dramatically.


During the luteal stage, the corpus luteum secretes progesterone and estrogen, which inhibits the secretion of FSH and LH. The lack of LH causes the corpus luteum to die at the end of this phase, recommencing the cycle (unless a fertilized ovum is implanted in the uterus).  


At the end of the article can be found a table which compares the female reproductive structures to their homologous male reproductive structures. The female terms which will be compared are italicized within the article.




External Genitalia

     Also known as the “pudendum”, the vulva consists of the visible portion of the vagina. Besides its importance in sexual stimulation, the vulva actually protects the urethral and the vaginal apertures. The main components of the vulva include the mons pubis, labia majora and minora, the vestibule, the clitoris and the urethral aperture. The adipose tissue associated with vulva’s structures is extremely sensitive to estrogen. After puberty, the estrogen hypertrophies these structures’ size; after menopause the same structures atrophy, due to lowered levels of estrogen. 

  • mons pubis
  • labia majora
  • labia minora
  • vestible
  • clitoris

Mons pubis

     Also known as the “mons veneris”, this structure is mainly composed of adipose tissue and skin. It lies directly above the pelvic bone, which it serves to protect during copulation. The mons pubis splits into the labia majora.   

Labia Majora (singular: labium majus)

     The labia majora is composed of two longitudinal cutaneous layers which come together at the posterior end of the vagina, in an area known as the perineum (right before the anus). The subcutaneous layers of the majora are made of sebaceous glands, sweat glands, loose connective tissue and adipose tissue. Underneath that subcutaneous layer, there is what is known as the bulbs of the vestibule. They are made up of erectile tissue which fills with blood during periods of arousal. Smooth muscle can also be found in subcutaneous layers of the labia majora; it is sensitive to temperature. Under colder conditions, the labia shrivel up and in warmer conditions they enlarge. The labia majora is covered with pubic hairs after puberty. 

Labia Minora (singular: labium minus)

     Also known as the “nymphae”, are the inner longitudinal layers which surround the urethral and vaginal apertures, as well as the vestibule. They develop anteriorly from the internal folds of the labia majora and join above and below the clitoris. The junction above the clitoris is referred to as the prepuce and the one below is the frenulum. The labia minora then stretch towards the posterior end, merging with the labia majora; this point is called the fourchette. The fourchette (also known as the frenulum labiorum pudendi) is usually torn after childbirth and sometimes after intercourse. The labia minora are also covered with sebaceous glands. With so many sebaceous glands on the vulva, a substance called sebum (it is mainly composed of fats and oils) is produced. Sebum helps to lubricate the skin. Combined with the sweat glands also found in the vaginal area, they form a water-proof coat that helps the vulva repel urine, menstrual blood and bacterial infections. The subcutaneous labia minora have sinuses which also become filled with blood during sexual arousal.  


     This structure directly surrounds the urethral and vaginal apertures. It contains a few ducts, including Bartholin’s glands which serves to lubricate the vestibule during sexual arousal. 


     This structure is used primarily in sexual arousal. It is composed of two crura, a shaft and a glans. The crura (singular: crus) connect to what is called the clitoral body and extend to opposite sides. The crura are made up of muscles called the ischiocavernosi and they join to form the shaft of the clitoris. The shaft of the clitoris contains two muscles, called the corpora cavernosa, which are made up of erectile tissue (they fill with blood during arousal). The shaft joins to create the clitoral hood. At the posterior end of the shaft is the clitoral glans, which has many nerves.




Internal structures of the female reproductive system

  • urethra
  • hymen
  • vagina
  • uterus
  • cervix
  • fallopian tubes
  • ovaries


    This structure is where urine passes through from the urinary bladder. The external urethral orifice is approx. 2.5 cm below the clitoris and contains Skene’s glands which are found on either side of the orifice. They secrete mucous which helps lubricate the orifice to aid in the passage of urine. The actual urethra is relatively short as compared to that of a male’s, it measures to be about 4 centimetres long.


     The hymen is a membrane which covers the vaginal orifice. It has no official function, but it may vary in texture (thin or thick) and is often ruptured during the first sexual intercourse.


     The vagina is a tube that extends from the cervix all the way to the vaginal aperture; it forms a 45° angle to the uterus. The dimensions of a vagina can and do vary, especially because of its ability to expand. In the superior- posterior portion of the vagina, is the cervix. 


     The vaginal lining is referred to as the vaginal epithelium. Much like skin, the epithelium consists of layers of cells which rest upon connective tissue, which contains blood vessels and nerves. However, it is a very tough epithelium because of its lack of sebaceous and/or sweat glands, meaning that microorganisms, such as bacteria, do not receive facilitated entry. The basal layers of the vaginal epithelium are more proximal to the blood vessels in the connective tissues, which allows them to proliferate in rapid response to the shedding of dead tissue. Estrogen also contributes to the thickness of the epithelium; as a result, before puberty and after menopause the vaginal epithelium is very thin.

     The vagina functions in reproductive activity, acts as a passageway for childbirth and as an outlet for menstrual flow.


     The uterus is a pink, hollow muscle. Its upper part is expanded and called the fundus, while its lower part is constricted and called the cervix. As with most body parts, the size of the uterus varies.  In females that have never been pregnant the uterus is quite small but is somewhat larger in women who have had children.  On average however, the uterus is about 3 inches long, 2 inches wide in the fundus and its wall is about ½ an inch thick. The uterine wall is very thick; it is made up of smooth muscle; called the myometrium. It is this muscular layer that contracts during labour to expel the fetus.  The uterine wall is called the endometrium; it is shed during menstruation (if fertilization does not occur). The uterus is supported and surrounded by the peritoneum, which is also called the perimetrium.

     The uterus helps direct blood flow towards the pelvic region during periods of arousal and also shelters and nourishes the fertilized egg.


            The cervix opens into the vagina via the external os; it opens into the uterine cavity via the internal os. This structure is mainly composed of connective tissue and smooth muscle fibres.

Fallopian Tubes

                Two fallopian tubes, also known as the oviducts,  contain 4 parts. The interstitial (or uterine) area is short, narrow, and within the uterus. The isthmus is straight, with a thick muscular wall and narrow lumen. The ampulla takes up about a ½ of the tube; it has a thin wall and very furrowed lining. Finally, the infundibulum is the structure which is most near the ovary; it has projections which are collectively called the fimbriae (singular: fimbria) – they work to sweep the ovum towards the opening of the tubes (called the ostium). The longest fimbriae and those closest to the ovary are referred to as the ovarian fimbria. The wall of the fallopian tubes contains many blood vessels and smooth muscle; the epithelium secretes a fluid which provides an accommodating environment required for movement, fertilization and nourishment to the ovum.


                Once the ovum has entered the ostium, it travels along the ampulla, and is stopped for a little more than a day at the ampullary-isthmus junction. The reason for this is to allow any sperm in the area enough time to fertilize the egg; if there is no sperm present, the ovum disintegrates and is phagocytized by macrophages.


            The ovaries functions as both an endocrine gland and a gonad. They produce secondary oocytes and hormones including progesterone and estrogen.  On average, they are about 3 cm long, 1 ½ cm wide and 1 cm thick; these grey organs are not covered with peritoneum. Instead they are connected to the pelvic cavity by the mesovarium (connective tissue which connects to the uterus’ peritoneum), by the ovarian ligament (which connects to the uterus itself) and the suspensory ligament (which is connected to the lateral side of the uterus).

            Ovaries are covered instead with what is called the germinal epithelium (a layer of cuboidal cells) which are on top of the cortex (this is where the ova develop). Within the cortex lies the medulla, which is simply a network of blood vessels, lymphatic vessels and nerves. A woman is born with  lifelong supply of  oocytes. 





Vascular Supply

     Most of the blood that arrives to the female reproductive system is supplied by branches of the uterine artery, the vaginal artery and the ovarian artery which all branch off the internal iliac artery or the abdominal aorta directly.




Nerve Supply

     The female reproductive system is under control of the autnomic nervous system. To be more specific, the parasympathetic and sympathetic nervous systems control the contraction and dilation of the blood vessels in the vaginal epithelium and the uterine smooth muscle. For the upper portion of the vagina, most sensory receptors (i.e. those for pain and touch) are located in the rectum and urinary bladder, rendering the upper portion relatively insensitive. The lower portion of the vagina however does contain a small amount of touch and pain receptors, which come from the pudendal nerve, whereas the vulva is filled with nerves. So, for example, if the vagina is infected, the vulvar area is the area that will feel irritated, even though the actual problem is within the body. The pudendal nerve is from the somatic portion of the autonomic nervous system.




Lymphatic Drainage

Lymphatic drainage of the female reproductive system primarily goes to the internal, external, superficial iliac nodes as well as the superficial and deep inguinal nodes. 



This table shows the male reproductive homologous structures to the women’s:

Female structure

Male structure

Labia majora


Bulbs of the vestibule

Corpora spongiosa

Subcutaneous smooth muscle of the labia majora

Dartos muscle of scrotum

Labia minora

Spongy urethra

Bartholin’s gland

Cowper’s gland


Crus of penis



Clitoral hood


Clitoral glans

Glans penis

Skene’s glands

Prostate gland







Resources and References

Sloane, E. (1980). Biology of women. Canada: John Wiley & Sons, Inc.




Tortora (2009). Principles of Human Anatomy 11th edition: John Wiley & Sons, Inc.


Marieb et al. (2008). Human Anatomy 5th edition: Pearson Benjamin Cummings

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