The female reproductive system
The ovaries, a pair of tiny glands in the female pelvic cavity, are the most important organs of the female reproductive system. Their importance is derived from their role in producing both the female sex hormones that control reproduction and the female gametes that are fertilized to form embryos.
Each ovary is a small glandular organ about the shape and size of an almond. The ovaries are located on opposite sides of the uterus in the pelvic cavity and are attached to the uterus by the ovarian ligament. The open ends of the fallopian tubes rest just beyond the lateral surface of the ovaries to transport ova, or egg cells, to the uterus.
The uterus, also commonly known as the womb, is a hollow muscular organ of the female reproductive system that is responsible for the development of the embryo and fetus during pregnancy. An incredibly distensible organ, the uterus can expand during pregnancy from around the size of a closed fist to become large enough to hold a full term baby. It is also an incredibly strong organ, able to contract forcefully to propel a full term baby out of the body during childbirth.
The uterus is approximately the shape and size of a pear and sits in an inverted position within the pelvic cavity of the torso. It is located along the body’s midline posterior to the urinary bladder and anterior to the rectum. The narrow inferior region of the uterus, known as the cervix, connects the uterus to the vagina below it and acts as a sphincter muscle to control the flow of material into and out of the uterus.
The vulva is the collective name for the external female genitalia in the pubic region, including the labia, clitoris, and urethral and vaginal openings. These organs work together to support urination and sexual reproduction.
The exterior of the vulva begins as a mound of skin-covered adipose known as the mons pubis that arises from the skin covering the pubis bone in the pubic region. As it continues inferiorly, the mons pubis divides laterally into the two parallel labia majora. The labia majora are wide folds of skin and adipose that rise beyond the mons pubis and surround the pudendal cleft, a deep vertical furrow in the center of the vulva. Both the mons pubis and labia majora are covered in pubic hair following puberty and serve to protect the delicate structures of the vulva found in the pudendal cleft.
The female reproductive system includes the ovaries, fallopian tubes, uterus, vagina, vulva, mammary glands and breasts. These organs are involved in the production and transportation of gametes and the production of sex hormones. The female reproductive system also facilitates the fertilization of ova by sperm and supports the development of offspring during pregnancy and infancy.
The breasts are a pair of milk-producing organs of the female reproductive system located on the left and right sides of the anterior thoracic (chest) region. Each breast projects outward from the anterior of the chest as a mass of skin-covered soft tissue. At the tip of the breast is a small cylindrical projection of erectile tissue called the nipple. The nipple is bordered by a ring of thickened, bumpy skin called the areola. Both the nipple and areola are highly pigmented compared to the surrounding skin of the breast, resulting in a darkened appearance.
The female reproductive system of the lower abdomen and pelvis contains all of the organs necessary for the fertilization of egg cells, development of an embryo and fetus during pregnancy, and delivery of a newborn baby.
The external female reproductive organs are known collectively as the vulva. Within the vulva are several folds of skin surrounding the urinary and reproductive orifices known as the labia majora and labia minora. These folds of skin cover and protect the clitoris, urethral opening, and vaginal opening. Within the labia minora and superior to the urethra is the clitoris, a sensitive erectile organ that is responsible for producing feelings of sexual arousal and pleasure.
Fertilization is the process of joining a spermatozoon and an ovum to form a zygote. Ova, also known as egg cells, are the haploid female gametes produced by the ovaries in the female reproductive system. At around the 14th day of the menstrual cycle, female sex hormones trigger the release of a mature ovum from one of the ovaries. The finger-like fimbriae of the Fallopian tubes sweep the surface of the ovaries to collect the ovum and place it into the hollow Fallopian tube. Once inside the Fallopian tube, the ovum is carried toward the uterus by many beating cilia in the lining of the tube and by peristaltic contractions of the tube. It is during this journey of the ovum toward the uterus that fertilization may occur.
Birth, also known as childbirth, parturition or partus, is the end point of pregnancy and results in the expulsion of newborn infants from the pregnant woman\'s uterus. Birth has three stages of labor: the cervix\'s shortening and dilation, the descent and birth of the infant, and the expulsion of the placenta. Birth can also be done via caesarean section; this is the removal of the newborn through a surgical incision in the abdomen, instead of through the vagina.
The Fallopian tubes, also known as the uterine tubes, are a pair of 4-inch (10 cm) long narrow tubes connecting the ovaries to the uterus. Ova (egg cells) are carried to the uterus through the fallopian tubes following ovulation. The ova may also be fertilized while in the Fallopian tubes if sperm is present following sexual intercourse.
The fetus inside the womb is actually called an embryo four weeks after it comes into existence. Around the time of implantation, certain cells within the blastocyst (an early stage of embryonic development) organize themselves into a group that will give rise to the body of the offspring. This marks the beginning of the embryonic period of development. The offspring is called an embryo until the end of the eighth week, after which it is a fetus. Eventually, the outer cells of the embryo together with cells of the maternal endometrium (wall of the uterus) form a complex vascular structure called the placenta. This organ serves to attach the embryo to the uterine wall, to exchange nutrients, gases, and wastes between the maternal blood and the embryonic blood, and to secrete hormones.