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| Female Reproductive System in Human |
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| The human female reproductive system performs the following functions: |
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| a) Formation of eggs |
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| b) Reception of sperms during copulation |
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| c) Providing a conducive environment for fertilisation |
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| d) Providing shelter and nourishment to the growing embryo. |
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| The female reproductive system is associated with the formation and maturation of the egg and the feeding and protection of the developing embryo inside the womb. |
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| Female Reproductive Organ |
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| The female reproductive organs include a pair of ovaries, a pair of fallopian tubes, uterus, vagina and vulva. |
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| Human ovaries are a pair of almond shaped structures about 3cm long, 1.5cm wide lying one on either side of the vertebral column in the abdominal cavity. Each ovary is attached to the dorsal abdominal wall by a mesentery called mesovarium. |
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| T.S. Mammalian Ovary |
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| Each ovary is covered by a layer of germinal epithelium. During embryonic life, the cells of the germinal epithelium proliferate thousands of primordial follicles. The stroma is composed of fibrous connective tissue which is differentiated into outer cortex and inner medulla. |
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| The cortex contains thousands of tiny undeveloped ovarian follicles. Medulla contains only blood vessels and nerve fibres. |
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| A fully mature ovarian follicle is called a Graafian follicle. It has an outer multilayered membrana granulosa formed of 2 - 3 layers of follicle cells. The oocyte is surrounded by a vitelline membrane, zona radiata and corona radiata. The oocyte is attached to the membrana granulosa by a group of cells called discus proligerus. The graafian follicle has a follicular cavity or antrum filled with a colourless follicular fluid. The fluid is termed as liquor folicelli. |
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| In human female, on an average every 28 days one graafian follicle matures and ruptures releasing an ovum. After this the follicle turns into the corpus luteum made up of large conical yellowish cells. Corpus luteum serves as a temporary endocrine gland, by releasing female sex hormones namely progesterone and estrogen. |
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| Ovary Histology |
| In a normal adult female, there are nearly four lakh follicles present in the two ovaries. Of them only one ovum matures and is liberated in each menstrual cycle by alternate ovaries. Others undergo regression and disappear due to death, during the reproductive years of the females. This phenomenon is referred to as follicular atresia. |
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| The maturation of the graafian follicle is under the control of the FSH and LH (Follicle Secreting Hormone and Luetinising Hormone). The interstitial cells of the ovary secrete the hormone estrogen. The progesterone is secreted by the corpus luteum. |
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| A pair of ciliated, muscular, tubular structures extend from the ovaries to the uterus. They are about 12 cm in length and is divided into 3 parts a funnel like opening lying close to the ovaries called infundibulum which opens into the peritoneal cavity by means of ostium, a middle dilated ampulla and the last part which opens into the uterus called as the isthmus. The fallopian tubes are kept in position by a mesentery attached to the uterus. |
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| It is involved in the conduction of ovum or zygote towards the uterus by peristalsis and it is also the site of fertilisation. |
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| It is a large, hollow, muscular, pear shaped, highly vascular organ present in the pelvis between the bladder and the rectum. It is about 8 cm long and 5 cm broad. It consists of a upper broad part called the body or corpus, a narrow uterine cavity or the internal as and a lower cylindrical part called the cervix. |
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| The thick uterine wall has 3 layers of endometrium which is highly vascular. The uterus opens into the vagina by a narrow cervix. |
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| The uterus harbours the developing embryo and provides it with nutrients and oxygen and removes the carbondioxide and wastes. |
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| It is the copulation chamber in females. It is about 7.5 cm long and extends backward in front of the rectum from the cervix. The vaginal opening is situated in the vestibule between the labia minora and the vulva. |
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| In the virgin state, a thin membranous diaphragm - the hymen is present at the vaginal orifice. |
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| It receives the sperms during copulation and is the birth canal during parturition. |
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| It is the external female genital organ. It includes the vaginal orifice, labia majora, labia minora, clitoris and Bartholin glands. The opening of the vagina is closed by 2 muscular folds of skin, the labia majora. Inside these are a pair of labia minora. A sensitive erectile organ about the size of a pea is present at the junction of the 2 labia minoria. It is called the clitoris and is homologous to the male penis. |
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| Bartholin Glands |
| These secrete mucus to lubricate the vagina at the time of mating and parturition. |
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| Breasts |
| These are a pair of rounded structures present on ventral thoracic wall with a nipple in its middle. The breast has about 20 lobes of mammary glands which are modified sweat glands. These lobes secrete milk to nourish the new born baby. Each lobe is separated from the others by dense connective and adipose tissues. Milk release in the female is regulated by certain hormones. |
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| Human Female Mammary Gland |
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| Hormonal control of the female reproductive system |
| 1) The hormones of the anterior pituitary gland namely LH (Leutinising hormone) and FSH (Follicle stimulating hormone) control the functioning of the female reproductive system. |
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| 2) The LH stimulates ovulation (rupture of the mature follicle to release ovum). |
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| 3) The LH also stimulates the secretion of the hormone progesterone. The release of LH by the anterior pituitary is in turn controlled by a hormone of the hypothalamus, Gonadotropin releasing hormone (GnRH). |
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| 4) Corpus luteum synthesises both estrogen and progesterone. Progesterone has many effects on the body. |
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| 5) The FSH, stimulates the secretion of estrogens. The release of FSH by the anterior pituitary is in turn controlled by a hormone, Gonadotropin releasing hormone (GnRH) of the hypothalamus. |
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| 6) The granulosa cells of the developing ovarian follicles synthesise oestrogen. Oestrogens are responsible for the development of the secondary sexual characteristics in mature women. |
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| 7) The levels of progesterone and oestrogen has a negative feedback control on the release of GnRH from the hypothalamus, i.e., a high level of estrogen or progesterone suppresses the release of GnRH and viceversa. |
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| Puberty in female |
| Puberty sets in between 10 - 14 years. It is characterised by the beginning of ovulation and the menstrual cycle. It is initiated by the hormone estrogen. |
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| It is characterised by an enlargement of breasts, broadening of the hip region, pubic and axillary hair growth, increase in subcutaneous fat in thighs and buttocks and stoppage of growth of long bones and height. |
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