Menstrual Cycle … This presentation is optimized for the biology students …
Puberty Menstruation Menstrual Cycle Menstrual Disorders Menstrual Cycle phases Index Just click on the topic you want to know
Puberty Puberty, period in the human lifespan during which the organs of sexual reproduction mature. It usually occurs in boys between the ages of 13 and 16, and in girls between the ages of 11 and 14. In males, production of body hair increases markedly, particularly in the pubic, axillary, and facial regions, and the voice usually changes and becomes deeper in tone. This maturation is evidenced in females by the onset of menstruation. In females, hair also appears in the pubic and axillary regions, and the breasts begin to grow. During puberty, rapid growth marks a range of physiological changes in both sexes. Various secondary sexual characteristics also appear for the first time with the enlargement of the external genitalia. Accelerated development of the sweat glands in both sexes may trigger acne.
Menstruation, periodic vaginal discharge in humans and other mammals, consisting of blood and cells shed from the lining of the uterus (endometrium). Each month the lining of the uterus thickens; if pregnancy does not occur, this lining breaks down and is discharged through the vagina. Menstruation Menstruation is part of the process that prepares a Girl for pregnancy. Menstruation accompanies a woman's childbearing years, usually beginning between the ages of 10 and 16, at puberty, and most often ceasing between the ages of 45 and 50, at menopause. The three to seven days that menstruation lasts is called the menstrual period
Menstrual Cycle In most women the menstrual cycle is about 28 days, but it can vary considerably even from one month to another. The cycle is initiated by hormones in the blood that stimulate the ovaries The egg passes through the Fallopian tube to the uterus. If the egg unites with a sperm on its way to the uterus, fertilization occurs and pregnancy ensues Each month, hormones cause an egg in one of the two ovaries to mature, that is, to become capable of being fertilized and develop into a foetus. The ovaries also produce hormones of their own, primarily oestrogen and progesterone, which cause the endometrium to thicken. About midway through the menstrual cycle, 14 to 15 days before the next period, the ovary releases the mature egg in a process called ovulation
Phases in Menstrual cycle Menstruation Pre-Ovulation Ovulation Follicular [Proliferative] phase Luteal [Pre-Menstrual] phase Menstrual [Bleeding] phase
Menstruation Day 1 of your cycle is the first full day of menstrual bleeding, The uterine lining built up in the previous cycle is cleared away, and the hormone levels from the previous cycle take a sharp decline, causing the physical and emotional symptoms commonly associated with menstruation.
Pre-Ovulation The pituitary gland releases a hormone called FSH (Follicle Stimulating Hormone), which stimulates an ovarian follicle to grow and an egg to mature. The pituitary gland also releases LH (Luteinizing Hormone) which stimulates the follicle to manufacture and secrete estrogen. Estrogen causes the uterine lining to grow.
Ovulation The pituitary gland releases a heavy surge of LH. 24 to 36 hours after the surge, the follicle will rupture, releasing the matured egg to the fallopian tube. The remainder of the ruptured follicle (called the corpus luteum) recedes back to the ovary and begins to secrete progesterone. Progesterone causes an increase in blood vessels to the uterine lining, inhibits other eggs from developing, and causes the Basal Body Temperature (BBT) to rise about half a degree.
Follicular [proliferative] phase 5th to 14th day This phase begins from the end of menstruation and with ovulation and generally involves 10 days. The development of graffian follicle is initialised by FSH and maintained by LH. The proliferative growth of endometrium is influenced and controlled by oestrogen hormone When the oestrogen is high in the ovary the FSH secretion is inhibited. This leads to further growth of follicles and at the same time stimulates the growth of the uterus. At the end of this follicular phase, Ovulation occurs. The combination of LH and FSH causes ovulation.
Luteal [pre-menstrual] phase 15th to 28th day In this progestational phase, the empty follicle after ovulation transforms into corpus luteum. This corpus luteum secretes Oestrogen and progesterone under the influence of LH. The progesterone acts on Uterus and causes the endometrium thicken and promote the endometrial glands. Also it prepares the uterus for the zygote reception and implantation. It inhibits the secretion of the LH and contraction of uterus. This stops the growt of ovarian follicles till the corpus luteum ceases to function. If implantation occurs, the corpus luteum functions throughout the pregnancy.
Menstrual [bleeding] phase 1st to 5th day This occurs only when the implantation of fertilized ovum is not accomplished. In this phase the superficial part of the endometrium is sloughed off and bleeding takes place due to rupture of blood capillaries. The corpus luteum ceases to function and is replaced by a scar tissue called corpus albicans.
Submit an assignment on Hormonal control of ovulation and Menstrual cycle
Amenorrhea the absence of periods Menorrhagia heavy prolonged menstrual bleeding Dysmenorrhea painful periods or menstrual cramps Menstrual Disorders Just click on the topic you want to know
Amenorrhea Amenorrhea (the absence of periods) is a clear signal of pregnancy. And in older non-pregnant women, amenorrhea may mean that menopause is approaching or has arrived — particularly if she is in her late 40s or 50s. In both groups of women, amenorrhea is perfectly normal.However in some cases amenorrhea can indicate an underlying medical problem. Primary amenorrhea is present when a young woman has not started to menstruate by age 16. This may be because she has some hormonal imbalance or developmental problem, which can often be treated with hormones and/or surgery. Amenorrhea, more commonly, affects women who have previously had normal periods. It is defined as an absence of menstruation for a length of time equivalent to a total of at least three of the previous cycle
Amenorrhea • Often a hormone imbalance is responsible for secondary amenorrhea. Frequently the body's level of gonadotropin-releasing hormone (GnRH) is low. This hormone is needed to control a woman's menstrual cycle and ovulation. GnRH levels can decrease because of a variety of reasons, such as excessive exercise, weight loss or weight gain, stress, or discontinuation of the birth control pill. • A hormone imbalance and amenorrhea can also result from • breast-feeding. (Note, however, that breast-feeding women may be ovulating, even though they're not having periods. They must use birth control to avoid pregnancy.) • ovarian cysts (fluid-filled sacs). • premature ovarian failure (early menopause). • problems with the adrenal glands (small glands above the kidneys). • thyroid conditions. • tumors (abnormal growths). • anorexia • other medical conditions • By the way, use of the birth control pill at a young age does not seem to be a factor in amenorrhea.
Dysmenorrhea Dysmenorrhea, the medical term for painful periods or menstrual cramps. The majority of women are thought to experience some degree of dysmenorrhea. Primary dysmenorrhea, no disease or other medical cause can be found for the pain and other symptoms, which may include backache, diarrhea, dizziness, headache, nausea, vomiting, and a feeling of tenseness. Primary dysmenorrhea frequently affects women in their teens and early 20s, who have never had a baby. The symptoms are caused by prostaglandin, a natural hormone produced by cells in the uterine lining. The level of prostaglandin increases in the second half of the menstrual cycle. When a woman’s period begins, the cells in the uterine lining release prostaglandin as they are shed. Women with severe primary dysmenorrhea have significantly higher prostaglandin levels in their menstrual fluid than do other women. The only good thing that can be said about primary dysmenorrhea is that usually the symptoms don’t last very long. Some women experience symptoms for up to one or two days, but rarely longer.
Dysmenorrhea • Secondary dysmenorrhea is caused by a physical condition. Women who suffer from it tend to be older than those with primary dysmenorrhea. Some conditions that may be responsible for secondary dysmenorrhea are • adenomyosis (uterine tissue growing into the uterine wall). • endometrial polyps (growths in the uterine lining). • endometriosis (uterine tissue that grows outside the uterus, in the ovaries and other locations). Endometriosis is the most common reason for secondary dysmenorrhea. • fibroids (growths in the uterus). • narrowing of the cervix (the entrance to the uterus) as it opens into the vagina. • pelvic inflammatory disease (PID). • use of an intrauterine device (IUD).
Menorrhagia MENORRHAGIA — heavy prolonged menstrual bleeding — knows how unpleasant, disabling and frightening, it can be. Sometimes the bleeding is so heavy that it's necessary to miss work, school, or social activities. It is defined as excessively heavy or prolonged bleeding (soaking through at least a pad an hour for several consecutive hours). And This is abnormal uterine bleeding, which may be caused by medical problems or hormone imbalances. Other types of abnormal uterine bleeding are too-frequent menstrual periods, bleeding between periods, and bleeding after menopause. In a normal menstrual cycle, there is a balance between estrogen and progesterone, two hormones in the body. These hormones regulate the buildup of the endometrium (uterine lining of blood and tissue), which is shed each month during menstruation. Menorrhagia can occur because of an imbalance between estrogen and progesterone. As a result of the imbalance, the endometrium keeps building up. When it is eventually shed, there is heavy bleeding. Because hormone imbalances are often present in adolescents and in women approaching menopause, this type of menorrhagia — known as dysfunctional uterine bleeding — is fairly common in these groups.
Acknowledgement & References Zoology Text book of XII std. By Tamil Nadu Text Book Society Encarta Encyclopedia http://www.onna.org/information/cycle.html http://www.womens-health.com/health_center/gynecology