FEMALE REPRODUCTIVE SYSTEM

            The female reproductive organs consist of the ovaries, uterine tubes, uterus, vagina, external genital organs, and mammary gland. The internal reproductive organs of the female are within the pelvis between the urinary bladder and the rectum. The uterus and the vagina are in the midline, with the ovaries to each side of the uterus. The internal reproductive organs are held in place within the pelvis by a group of ligaments. The most conspicuous is the broad ligament, an extension of the peritoneum that spreads out on both sides of the uterus and to which the ovaries and urine tubes are attached.

Ovaries

          The two ovaries are small organs about 2-3,5 cm long and 1-1,5 cm wide. Each is attached to the posterior surface of the broad ligament by a peritoneal fold called the mesovarium. Two other ligaments are associated with the ovary : the the suspensory ligament, and the ovarian ligament.

·         Ovarian histology

            The peritoneum covering the surface of the ovary is called the ovarian, or germinal, epithelium because is once thought to produce oocytes. Immediately below the epithelium a layer of dense, fibrous connective tissue, the tunica albuginea, surrounds the ovary. The ovary itself consists of a dense outer part called the cortex and a looser inner part called the medulla. Blood vessels, lymph vessels, and nerves from the mesovarium enter the medulla. Numerous small vesicles called ovarian follicles, each of which contains an oocyte, are distributed throughout the cortex.

·         Follicle and oocyte development

            Oogenesis is the production of a secondary oocyte within the ovaries. By the fourth month of parental life, the ovaries can contain 5 million oogenia, the cells from which oocyte develop. By the time of birth many of the oogenia have degenerated, and those remaining have begun meiosis. Meiosis stops, however. During the first meiotic division at a stage called prophase I. the cell at this stage is called a primary oocyte, and at birth there are about 2 million of them. The primary oocyte is surrounded by a single layer of flat cell called granulose cells, and the structure is called a primordial ooctye. From birth to puberty the number of primordial oocytes decline to around 300,000-400,000 of these only400 continue oogenesis and are released from the birth at puberty, the cyclical secretion of FSH stimulates the development of a small number of primordial follicles. Primordial follicle is converted to a primary follicle of the oocyte enlarge and the single layer of granulose first become enlarged and cuboidal. Subsequently several layers of granulose cells from, and a layer of clear material posited around the primary oocyte called the zona pelusida.

            Some of the primary follicles continue development and some secondary follicles. The granulose cells multiply form an increasing number of layers around the oocyte. small spaces called vesicles, which are fluid-filled. Among the granulose cells. The vesicles ultimately fuse form a single chamber called the antrum. As the secondary follicle enlarges, surrounding cell are molded and it to form the theca, or capsule. Two layer can be recognized around the secondary follicles vascular theca interna and the fibrous theca interna.

·         Ovulation

As the graafian follicles continues to swell, it can be seen on the surface of the ovary as a tight, translucent blister. The follicular cells secrete a thinner fluid than previously and at an increased rate so that the follicle swells more rapidly than can be accommodated by follicular growth. As a result, the granulose cells and theca become very thin over the area exposed to the ovarian surface.

            The graafian follicles expand and ruptures, forcing a small amount of blood and follicular fluid out of the vesicle. Shortly after this initial burst of fluid, the secondary oocyte. Surrounded by the cumulus mass and the zona pellucid, escapes from the follicle. The release of the secondary oocyte is called ovulation.

            During ovulation. Development of the secondary oocyte has stopped at metaphase II. It sperm cell penetration does not occur, the secondary oocyte never complete this second division and simply degenerates and passes out of the system. Continuation of the second meiotic division is triggered by fertilization, the entry of a sperm cell penetrates the secondary oocyte. Once the sperm cell penetrates the secondary oocyte. The second meiotic division is completed, and a second polar body is formed. The fertilized oocyte is now called a zygote.

·         Uterine tubes

            There are two uterine tubes, also called fallopian tubes, or oviducts, one on each six of the uterus and each associated with one ovary. Each tube is located along the superior margin of the broad ligament. The part of the broad ligament most directly associated with the tubes is called the mesosalpinx.

            The uterine tube open directly into the peritoneal cavity to receive the oocyte and expand to form the infundibulum. The opening of the infudibulum. The ostium. Is surrounded by long. Thin processes called fimbriae. The inner surface of the fimriae consist of a ciliate mucous membrane.

            The part of the uterine tube that is nearest to the infundibulum is called the ampulla. It is the widest and longest part of the tube and account for about 7,5-8 cm of the total 10 cm length of the tube. The part of the tube nearest the uterus, the isthmus, is much narrower and has thinner walls than does the ampulla. The uterine, or intramural, part of the traverses the uterine wall and ends in a very small uterine opening.

            The wall of each uterine tube consists of three layer. The outer serosa is formed by the peritoneum. The middle muscular layer consist of longitudinal and circular smooth membrane of simple ciliated columnar epithelium. The mucosa is arranged into numerous longitudinal told.

            The mucosa of the uterine tubes provides nutrients for the oocyte, or developing embryonic mass if fertilization has occurred as long as it is traversing the uterine tubes. The ciliated epithelium help move the small amount of fluid and the oocyte through the uterine tubes.

·         Uterus

            The uterus is size and shape of a medium sized pear and is about 7,5 cm long and 5 cm wide. It is slightly flattened anteroposteriorly and is oriented in the pelvis cavity with the larger, rounded part, the fundus meaning, bottom of a rounded flask directed superiorly and the narrower part, the cervix meaning, neck directed inferiorly. The main part of the uterus, the body, is between the  fundus and the cervix. A slight constriction called the isthmus marks the junction of the cervix and the body. Internally, the uterine cavity continues as the cervical canal, which opens trough the ostium into the vagina.

            The major ligaments holding the uterus in place are the broad ligament, the round ligament, and the uterosacral ligament. The round ligament extend from the uterus through the inguinal canals to the labia majora of the external genitalia. And the uterosacral ligaments attach the uterus to the sacrum. Normally the uterus is anteverted, meaning that the body of the uterus is tipped slightly anteriorly. In some woman the uterus can be retroverted, or tipped posteriorly. In adition to the ligaments. Much support is provided interiorly to the uterus by the skeletal muscles of the pelvis floor. If these muscle are weakened the uterus can extend inferiorly into the vagina, a condition called a prolapsed uterus.

             The uterine wall is composed of three layers, serous, muscular and muscular. The perimetrium, or serous layer, of the uterus is the peritoneum that covers the uterus. The next layer, just deep to the perimetrium, is the myometrium, or muscular coat, which consists of a thick layer of smooth muscle. The myometrium accounts of the bulk of the uterine wall and is the thickest layer of smooth muscle in the body. In the cervix the muscular layer contains less muscle and more dense connective tissue. The cervix is therefore more rigid and less contractile than the rest of the uterus. The innermost layer of the uterus is the endometrium, or mucous membrane. The endometrium consists of a simple columnar epithelial lining and a connective tissue. The lamina propria and open through the epithelium into the uterine cavity. The endometrium consists of two layers a thin, deep basal layer, which is the deepest part of the lamina propria and is continuous with the myometrium, and a thicker, superficial functional layer, which consists of most of a lamina propria and the endothelium and lines the cavity itself. The functional layer is so named because it undergoes menstrual changes and sloughing during the female sex cycle.

            The cervical canal is lined by columnar epithelial cell and contains cervical mucous glands. The mucus fills the cervical canal and acts as a barrier to substances that could pass from the vagina into the uterus. Near the time of ovulation the consistency of the mucus changes, making the passage of sperm cells from the vagina into the uterus easier.

Vagina

            The vagina is a tube about 10 cm long that extends from the uterus to the outside of the body. The vagina is the female organ of copulation, functioning to receive the penis during intercourse, and it allows menstrual flow and childbirth. Longitudinal ridges called columns extend the length of the anterior and posterior vaginal walls, and several transverse ridges called rugae extend between the anterior and posterior columns. The superior domed part of the vagina, the fornix, is attached to the sides of the cervix so that a part of the cervix extend into the vagina.

            The wall of the vagina consists of an outer muscular layer and an inner mucous membrane. The muscular layer is smooth muscle that allows the vagina to increase in size to accommodate the penis during intercourse and to stretch greatly during delivery. The mucous membrane is moist stratified squamous epithelium that form a protective surface layer. Most of the lubricating secretions produced by the female during intercourseare released by the vaginal mucous membrane.

             The vaginal opening, or orifice, is covered by a thin mucous membrane called the hymen. Sometimes the hymen completely closes the vaginal opening, and it must be removed to allow menstrual flow. More commonly to hymen is perforated by one or several holes. The openings in the hymen are usually greatly enlarged during the first sexual intercourse. In addition, the hymen can be perforated or torn at some earlier time in a young woman’s life. Such as during strenuous physical exercise. Thus the absence of an intact hymen does not necessarily indicate that a woman has had sexual intercourse as was once thought.

External genitalia

            The external female genitalia also referred to as the vulva or pudendum. The vestibule is the space into which the vagina open a pair of thin. Longitudinal skin folds called the labia meaning, lips minora. A smooth erectile structure called the clitoris is located the anterior margin of the vestibule. Anteriorly the two labia minora unite over the clitoris to form a fold of skin called to prepuce.

            The clitoris is usually less than 2 cm in length a consist of a shaft and a distal glans. It is well supplied will sensory receptors and function to initiate and intensify level of sexual tension. The clitoris contain two erectile structure the corpora cavernosa. Each of which expands at the by end of the clitoris to form the crus of the clitoris attaches the clitoris to the coxae. The corpora cavernosa of penis and they became engorged with blood as a result sexual excitement. In the diameter but not the length, of clitoris. With increased diameter the clitoris makes be contact with the prepuce and surrounding tissues and is neasly stimulated.

Perineum

            The perineum as in the male, is divided into two triangles by the superficial and deep transverse perineal muscles. The anterior urogenital triangles contains the anal opening. The region between the vagina and the anus is the clinical perineum. The skin and muscle of this region can tear during childbirth. To prevent such tearing an incision called an episiotomy sometimes is made in the clinical perineum. This clean straight incision is easier to repair than a tear would be. Alternatively, allowing the perineum to stretch slowly during the delivery may prevent tearing, making an episiotomy unnecessary.

Mammary glands

            The mammary gland are the organ of milk production and are located within the mammae or breasts. The mammary glands are modified sweat glands. Externally the breasts of both males and females have a raised nipple surrounded by a circular pigmented areola. The areolae normally have a slishtly bumpy surface caused by the presence of rudimentary mammary glands, called areolar glands, just below the surface. Secretions from these glands protect the nipple and the areola from chafing during nursing.

            In prepubescent children the general structure of the breasts is similar and both males and females process a rudimentary glandular system which consists mainly of ducts with sparse alveoli. The female breasts begin to enlarge during puberty primarily under the influence of the estrogen and progesterone. This enlargement is often accompanied by increased sensitivity or pain in the breasts. Males often experience these same sensations during early puberty and their breasts can even develop slight swelling, however these symptoms usually disappear fairly quickly. On rare occasions the breasts of a male become enlarged a condition called gynecomastia.

            Each adult female mammary gland usually consists of 15-20 glandular lobes covered by a considerable amount of adipose tissue. It is primarily this superficial fat that gives the breasts its form. The lobes of each mammary gland form a conical mass with the nipple located at the apex. Each lobe possesses a single lactiferous duct, which opens independently of other lactiferous ducts on the surface of the nipple. Just deep to the surface each lactiferous duct enlarges to form a small pindle-shaped lactiferous sinus, which accumulate milk during milk production. The lactiferous duct supplying a lobe subdivides to form smaller duct each of which supplies a lobule. Within a lobule the duct branch and become even smaller. In the milk-producing breast the ends of these small duct expand to form secretory sacs called alveoli.

            The mammae are supported and held in place by a group of mammary or cooper’s ligaments. These ligament expand from the fascia over the pectoralis major muscle to the skin over the mammary gland and prevent the mammary ligament weaken and elongate allowing the breast to sag to a greater extent than when the person was younger.

The nipples are very sensitive to tactile stimulation and contain smooth muscle That can contract causing the nipple to become erect in response to stimulation. These smooth muscle lubers respond, like other erectile tissues during sexual arousal.