MENSTRUAL CYCLE
Saturday, April 22, 2023
6:56 PM
MENSTRUAL CYCLE refers to natural changes that occur in the female reproductive system each month during the reproductive years,
except when a woman is pregnant.
A typical menstrual cycle averages 28 days in length but may vary normally from 21 to 45 days. The average
menstrual period is five days long, but may vary normally from two to seven days. These variations in the
menstrual cycle may occur both between women and within individual women from month to month.
MENARCHE - occurs around age 12 or 13
MENOPAUSE - occurs around age 52
PHASES OF MENSTRUAL CYCLE
MENSTRUAL CYCLE - DAYS 1-4
FOLLICULAR PHASE - DAYS 5 - 13
OVULATION PHASE - DAY 14
LUTEAL PHSE - DAY 15-28
MENSTRUAL CYCLE
- MENSTRUAL OCCURS
FOLLICULAR PHASE
- pituitary gland releases (FSH) to create follicles which contain an immature egg.
As follicle matures, body releases extra estrogen which stimulates the uterine lining to thicken to provide
the necessary nutrients to a fertilized egg.
OVULATION PHASE
- starts when rising estrogen levels signal the pituitary to release of LH to stimulates the ovulation process.
LUTEAL PHASE
- If the mature egg is fertilized, the body will produce Human Chorionic Gonadotropin (HCG) that will
help to keep the uterine lining thick for the fertilized egg to develop into an embryo.
if the egg doesn't get fertilized during ovulation, the corpus luteum will be dissolve into the body and
disappear
POSITIVE AND NEGATIVE FEEDBACK MECHANISM IN MENSTRUAL CYCLE
POSITIVE FEEDBACK
increasing levels of hormones feedback directly
to the hypothalamus and pituitary gland to decrease the hormones production
NEGATIVE FEEDBACK
increasing levels of hormones present feedback for the hormone production to increase
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