The Menstrual Cycle
the process of ovulation and menstruation in women and other female primates
The 4 Stages
- The pituitary gland secretes a hormone that stimulates the egg cells in the ovaries to grow.
- One of these egg cells begins to mature in a sac-like-structure called follicle. It takes 13 days for the egg cell to reach maturity.
- While the egg cell matures, its follicle secretes a hormone that stimulates the uterus to develop a lining of blood vessels and soft tissue called endometrium.
day 1 to 13
- The pituitary gland secretes a hormone that causes the ovary to release the matured egg cell.
- The released egg cell is swept into the fallopian tube by the cilia of the fimbriae.
- Due to the influence of estrogens, cervical fluids increase and become more fertile.
- A sudden increase of the LH hormone acts on the ovarian follicle, breaking down the surface of the follicle where the egg is housed. As LH rapidly increase, a hole appears in the follicle surface.
- Ovulation takes place when the egg is released from the follicle.
- The egg cell released during the ovulation phase stays in the fallopian tube for 24 hours.
- If a sperm cell does not impregnate the egg cell within that time, the egg cell disintegrates.
- The hormone that causes the uterus to retain its endometrium gets used up by the end of the menstrual cycle. This causes the menstrual phase of the next cycle to begin.
day 15 to 28
- The uterus sheds its inner lining of soft tissue and blood vessels which exits the body from the vagina in the form of menstrual fluid.
- Blood loss of 10 ml to 80 ml is considered normal.
- You may experience abdominal cramps. These cramps are caused by the contraction of the uterine and the abdominal muscles to expel the menstrual fluid.
day 1 to 5
Amenorrhea can occur for a variety of reasons. Some are normal during the course of a woman's life, while others may be a side effect of medication or a sign of a medical problem.
The main sign of amenorrhea is the absence of menstrual periods. Depending on the cause of amenorrhea, you might experience other signs or symptoms along with the absence of periods, such as:
- Milky nipple discharge
- Hair loss
- Vision changes
- Excess facial hair
- Pelvic pain
During your menstrual period, your uterus contracts to help expel its lining. Hormone-like substances involved in pain and inflammation trigger the uterine muscle contractions. Higher levels of prostaglandins are associated with more-severe menstrual cramps.
Severe contractions may constrict the blood vessels feeding the uterus.
- Throbbing or cramping pain in your lower abdomen that may be intense
- Dull, constant ache
- Pain that radiates to your lower back and thighs
Exactly what causes premenstrual syndrome is unknown, but several factors may contribute to the condition:
- Cyclic changes in hormones
- Chemical changes in the brain
- Tension or anxiety
- Depressed mood
- Crying spells
- Mood swings and irritability or anger
- Appetite changes and food cravings
- Trouble falling asleep (insomnia)
- Social withdrawal
- Poor concentration
- Joint or muscle pain
- Weight gain related to fluid retention
- Abdominal bloating
- Breast tenderness
- Acne flare-ups
- Constipation or diarrhea
Menopause is defined as occurring 12 months after your last menstrual period and marks the end of menstrual cycles. Menopause can happen in your 40s or 50s. Menopause is a natural biological process. Although it also ends fertility, you can stay healthy, vital and sexual. Some women feel relieved because they no longer need to worry about pregnancy.
Menopause can result from:
- Natural decline of reproductive hormones
- Chemotherapy and radiation therapy
- Primary ovarian insufficiency
- Irregular periods
- Vaginal dryness
- Hot flashes
- Night sweats
- Sleep problems
- Mood changes
- Weight gain and slowed metabolism
- Thinning hair and dry skin
- Loss of breast fullness