Human Female Reproductive System
the female reproductive system consist of those organs that maintain the female sex cells (oocytes), transport the cell to the site of fertilization, provide a favorable environment for a developing offspring (fetus), move the fetus to the outside and provide a female sex hormones. The female’s primary sex organs includes two ovaries and the accessory organs, which are the external accessory organs and the internal accessory organs.
The ovaries are ovoid, solid structure; they lie in shallow depression in the lateral wall of the pelvic cavity. The ovaries are held in place by three ligaments.
(1) Broad ligament: this are fold of peritoneum.
(2) Ovarian ligament: this ligament holds the ovary to the uterus.
(3) Suspensory ligament: this ligament attaches the ovary to the posterior side of the pelvic wall.
PARTS OF OVARY
The ovary are made up of the following types
(1) Germinal epithelium: this is the outer most covering of the ovary
(2) Tunica albuginea: this type is composed of connective tissue deep to germinal epithelium.
(3) Ovarian cortex: this is a dense connective tissue and is composed of ovarian follicle and stromal cell.
(4) Ovarian medulla: this is composed of a loose connective tissue, blood vessels, lymphatic vessels, and nerve fibers.
(5) Hilum: this is where blood vessels, nerves enter and leave the ovary.
(6) Ovarian follicle: These are tiny masses of cell surrounding the ovary. They are formed by the stromal cells.
(7) Mature follicle: this are large fluid-filled that are ready to burst.
(8) Corpus luteum: this are remnants of mature follicle, this type of the ovary produces hormones. They are the derived from ovarian follicle.
(9) corpus albican: this are masses of fibrous tissues formed at the end of corpus luteum.
Primordial follicles possess primary oocytes that consist of a single, large cells. They are closely surrounded by epithelial cells called follicular cells. The primary oocytes undergo meiosis during prenatal development in female but stops until the individual reaches puberty. Once the primordial follicle appears, no new once forms instead the numbers of oocytes in the ovary steadily declines as many degenerates. The ovary releases fewer than 400-500 oocyte during female’s reproductive life.
Oogenesis is the process of egg cell formation. At the beginning of puberty some primary oocyte are stimulated to continue meiosis, which is the process of cell division that occurs in the formation of reproductive cells. When primary oocytes divides, the distribution of the cytoplasm is unequal. One of the resulting cell called secondary oocytes (egg cell) is large and the other called the polar body is small. This large secondary oocyte can be fertilized by a sperm cell. During fertilization, the secondary oocyte divides unequally to produce a tiny second polar body and large fertilized egg cells called a zygote. The polar bodies has no further function and soon degenerates.
During maturation the primary oocyte enlarges and the surrounding follicular cells proliferates by mitosis, which is a cell division in which the daughter cells has chromosomes, which are identical in number and genetic content to those of the mother cells. These follicular cells organize into layers and soon a cavity appears in the cellular masses. A clear follicular fluid fills the cavity and bathes the primary oocyte; this fluid filled cavity passes the primary oocyte to one side. When the mature follicle reaches a diameter of 10 millimeters, it bulges outward on the ovary surface like a blister. The secondary oocyte is surrounded by a layer of glycoprotein known as the zona pellucida and attached to a mantle of follicular cells (corona radiata). Processes from the follicular cells extends through zona pellucida and supply the secondary oocyte with nutrients.
Ovulation is the shading away of ovum from the ovary. A Primary developed oocyte enlarges and becomes surrounded by follicular cells and fluid as the follicle matures. When the follicle ruptures, it releases secondary oocytes. The secondary oocyte is expelled into peritoneal cavity and swept into the uterine tube. In the uterine tube, the secondary oocyte unites with a sperm, but if the oocyte is not fertilized within a relatively short time, it degenerates.
THE ACCESSORY ORGANS OF THE FEMALE REPRODUCTIVE SYSTEM
(1) The female internal accessory organs are made up of three parts, which includes two uterine tubes, a uterus, and vagina.
UTERINE TUBE: the uterine tubes also known as fallopian tubes passes medially to the uterus and opens into the uterine cavity. Near the ovary the uterine tube expands forming a funnel shaped portion called infundibulum, it possess a fringe of finger-like projection called fimbriae. The widest region of the uterine tube is called the ampulla of uterine tube while the thin part that empties into the uterus is called isthmus of uterine tube.
UTERUS: the uterus is the organ of the female reproductive system that receives the embryo and sustains its development. It is a hollow muscular organ with an inverted pear shape, its size changes during pregnancy. It is located medially with the anterior portion of the pelvic cavity, superior to the vagina.
PARTS OF THE UTERUS
The parts of the uterus includes:
(1) Fundus: this is the superior portion of the uterus.
(2) Body: this is the tapering central portion containing the uterine cavity
(3) Cervix: This inferior and narrow portion opens into the vagina. It also contains a cervical carnal with internal os leading to the uterine and external os leading the vagina.
Several ligaments maintain the uterus
(1) Broad ligament: this is the part of the peritoneum; it attaches the uterus to either side of the pelvic cavity.
(2) Uterosacral ligament: this ligament connect the uterus to the sacrum
(3) Cardinal ligament: the cardinal ligament extends to the pelvic wall.
(4) Round ligament: this ligament extends from uterus to labia majora of external genitalia.
THE LAYER OF THE UTERUS
The uterus are made up of three layers
(1) Perimetrium layer: This outer serosa layer covers the body of the uterus and part of the cervix and becomes the broad ligament.
(2) Myometrium layer: This is a thick, middle, muscular layer and consist of bundles of smooth muscle fibers.
(3) Endometrium layer: This is the inner mucosa layer covered with columnar epithelium and contains tubular glands. The endometrium is sub-divided into two layers, the stratum functionalis which lines uterine cavity and sloughs off during menstruation. In addition, the stratum basalis which forms new stratum functionalis.
VAGINA: The vagina is a tubular, fibro muscular canal extending from the uterus to the outside. It carries uterus secretion, receives penis during sexual intercourse and provides an open channel for the offspring during birth. The vagina has a fornix which is the recessed area surrounding the cervix. It also has a fugae, which a ridge in the mucosa layer of vagina. In addition, hymen, a thin fold of mucosa layer bordering around the vaginal orifice.
THE FEMALE EXTERNAL REPRODUCTIVE ORGANS
This includes the labia majora, labia minora, clitoris, and vestibular glands.
(1) Labia majora: This two longitudinal skin folds encloses and protects the external reproductive organs. A cleft, which includes the urethra and vaginal opening, separates the labia longitudinally. At the anterior ends, the labia merge to form a medial rounded elevation of adipose tissue called Mons pubis.
(2) Labia minora: this are two small skin folds devoid of pubic hair and fat between the labia majora. They are richly supplied with blood vessels, giving it a pinkish appearance.
(3) Clitoris: the clitoris is small cylindrical mass of erectile tissue at the anterior end of the vulva between the labia minora. The clitoris corresponds to the penis in men and has a similar structure. The clitoris is composed of two erectile tissue called corpora cavernosa, and contains a small mass of erectile tissue called glans, which is supplied with sensory nerve fibers.
(4) Vestibule: the vestibules are regions between the labia minora; it includes an external urethra orifice, a vagina orifice, and opening of the ducts of several glands. A pair of vestibular glands lies one on either side of the vaginal opening; beneath the mucosa of the vestibule on either side is a mass of vascular erectile tissue called the vestibular bulb.
THE MAMMARY GLANDS
This is also an accessory organ of the female reproductive system. They are specialized in secreting milk after childbirth.
STRUCTURE OF THE BREAST
The breast is consist of a nipple located near the tip of each breast; it is a pigmented projection with closely spaced opening of lactiferous ducts where milk emerges. The breast is composed of areola, a circular pigmented area of skin that surrounds the nipple. the mammary glands has like fifteen to twenty lobes, each of the lobes contains an alveolar glands and an alveolar ducts that leads to the lactiferous ducts which then leads to the nipple and opens to the outside. Other connective tissue forms dense strands supporting the breast called suspensory ligaments. A lactiferous sinus; an expanded area of ducts store milk.
FUNCTIONS OF THE FEMALE REPRODUCTIVE ORGANS
produces oocytes and female sex hormones
transport secondary oocyte to uterus
site of fertilization, ovum implantation, protects and sustain embryo during pregnancy
is a passageway for childbirth.
encloses and protects other external reproductive organs
form margins of vestibules, protects opening of vagina and urethra.
produces feelings of pleasure during sexual stimulation
space between labia minora that contains vaginal and urethra openings
secretes fluid that moistens and lubricates vestibule.
synthesize, secrete, and ejects milk for new born