A guide to the Female Anatomy and Reproductive System
This article provides an overview of the location and function of the various internal reproductive female sex organs and external structures of the female anatomy.
The internal female organs are the organs which are not visible. They are sometimes referred to as the reproductive organs and the major organs of this system include the ovaries, fallopian tubes, uterus and vagina.
The vagina is a stretchy canal made of expandable muscle which connects the external vaginal opening or introitus to the cervix. It can range from 6.5 to 12.5cm in length and ranges from 2 to 3.5cm in diameter.
The vaginal fornices are located at the top of the vagina, where the vaginal walls curve inwards and are arched recesses surrounding the cervix. The fornix is divided into an anterior fornix at the front, posterior fornix at the back and a left and right lateral fornix. The anterior fornix is also referred to as the A-spot or anterior fornix erogenous zone (AFE zone) and is sensitive to stimulation.
During childbirth, the vagina also acts as a birth canal.
When a female gets her period, menstrual fluid leaves the uterus through the cervix then through the vagina. The vagina is where a tampon or menstrual cup is worn during menstruation.
The g-spot is an abbreviation for the Gräfenberg spot. It is an erogenous zone located on the front wall of the vagina that leads to sexual arousal when stimulated.
The cervix is the portion of the uterus which connects the vagina to the uterus. The cervix can range from 2 to 5cm in length and the cervical position can vary from person to person and may vary position throughout the menstrual cycle.
The os is part of the cervix. The external os connects the vagina to the cervical canal and is also referred to as the ectocervix whilst the internal os connects the cervical canal to the uterus and is referred to as the endocervix.
Hormones cause the cervix to produces mucus which changes in colour and consistency throughout the menstrual cycle. The cervix also dilates or expands during childbirth.
The uterus, or womb, is a hollow organ which is held in place by the broad ligament. It is generally an inverted pear-shaped organ however uterine anomalies can occur resulting in a different uterus shape.
The uterus wall comprises of three layers; the endometrium, myometrium and perimetrium.
The innermost layer of the uterine cavity is the endometrium. This tissue thickens in preparation for pregnancy every month. If conception occurs, the embryo embeds in the endometrium. If conception does not occur, the endometrium sheds during menstruation.
The myometrium is the muscular layer in the middle and the outermost layer is perimetrium. The perimetrium is a thin serous layer which secretes lubricating fluid to prevent friction caused by muscle movement.
The ovaries are two almond-sized glands located on either side of the uterus. They are held in place by an ovarian ligament.
The role of the ovaries is to produce hormones and contain the ova or eggs required for reproduction. Ovarian follicles are sac-like structure, containing a single oocyte or immature egg or ovum. A mature ovum is released from the follicle each month during ovulation.
The corpus luteum is the structure which remains after the egg has been released from the follicle. The corpus luteum produces progesterone which thickens the lining of the uterus necessary for a healthy pregnancy.
The ovaries contain approximately 2 million eggs at birth and never produce any additional eggs. The number of eggs reduces over time and at the start of menstruation, a girl will have 300,000 to 500,000 eggs.
Fallopian tubes, also referred to as the uterine tubes or salpinges, connect the ovaries to the uterus and carry the egg to the uterus each month. The ampulla is the portion of the fallopian tube which curves over the ovaries and the infundibulum is the funnel-shaped opening nearest to the ovary which channels the released egg into the fallopian tube.
Collectively, the external female structures are referred to as the genitals or vulva. The vulva includes the labial lips, clitoris and urethra and vaginal opening.
These external structures have three functions; they protect the internal organs from infection, enable sperm to enter the body and provide sexual pleasure. There is a wide range of variances in the physical appearance of the female genitalia.
The mons veneris is also known as the mons pubis. It is a fatty cushion which rests on the front surface of the pubic bone. It acts as a protective cushion, particularly during intercourse and is the area pubic hair begins to grow from during puberty. The mons pubis also contains sebaceous glands that release pheromones which are responsible for sexual attraction.
The labia is made up of two parts; the labia majora and labia minora. These Latin terms literally translate to large lips and small lips.
The labia majora are the outer lips that start at the mons and continue to the perineum. They are covered with pubic hair and contain sweat and sebaceous glands. The labia minora are two smaller folds of skin that lie within the labia majora and the vaginal opening. The labia minora join at the top near the pubic bone to form a hood over the clitoris. These smaller labial lips protect the entrance to the vagina and urethra from infection. The labia minora also have a rich supply of blood vessels which make them pink in colour. During sexual stimulation, these blood vessels become encouraged with blood and become more sensitive.
The clitoris is located just above the urethral opening. It is roughly the size of a pea and has a shaft which extends into the body. The clitoris is very sensitive as it contains lots of nerve endings. The clitoris swells with blood during sexual arousal or when stimulated and the stimulation of the clitoris can lead to an orgasm. The clitoris has a fold of skin surrounding it called the clitoral hood or prepuce.
The urethral opening is the point where urine exits the bladder via the urethra.
The introitus is the entrance into the vaginal canal. It is the exit point for menstrual fluid and vaginal secretions or discharge and the entry point during intercourse. During intercourse, the introitus and vagina stretch then shrinks back to their original size. It can vary in diameter from 2.4 to 6.5 cm.
In most adolescent girls, a thin membrane called the hymen surrounds or partially covers the vaginal opening. The hymen may stretch or tear, sometimes referred to as "breaking the hymen", for a number of reasons including; penetration, masturbation, physical examination, exercise or due to other medical reasons. An imperforate hymen completely covers the vaginal opening, sealing it shut. Although fairly rare, early detection of this condition is important to allow menstrual blood to flow freely and prevent endometriosis.
The female perineum is a diamond-shaped area of tissue between the thighs, anus and vagina and is divided into a urogenital triangle at the top and an anal triangle. During childbirth, the muscle and skin between the vagina and anus stretch to allow for childbirth. The premium may tear or need to be cut during childbirth.
The vulva vestibule is the entire region between the labia minora and urethral opening and includes the vagina and two types of glands.
Bartholin’s glands are located beside the vaginal opening. They are sometimes referred to as the or greater vestibular glands and their function is to secrete a mucosal fluid to lubricate the vagina during penetration.
Skene's glands are known as the lesser vestibular glands, periurethral glands, paraurethral glands or the female prostate. They are located on the upper wall of the vagina, below the urethra and is said to be responsible for female ejaculation.
The internal organs of the female reproductive system perform the following functions;
- ovaries produce eggs
- fallopian tubes transport the eggs to the uterus
- the uterus allows for the nurturing of a fertilized egg and development of the fetus or the uterus lining is shed during menstruation if conception does not occur
- the vagina provides a birth canal for the baby
- mammary glands and breast allow for the production and secretion of milk for feeding offspring
The external structures of the female anatomy protect the internal organs from infection, enable sperm to enter the body and provide sexual pleasure.