cycle is a series of changes that takes place in the female reproductive system to allow for the possibility of pregnancy.
Fig. 5 The menstrual cycle.
Menstruation The release of the uterus lining, unfertilised egg and blood through the vagina.
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Ovulation The release of an unfertilised egg from the ovary.
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While menstruation is happening, another tiny egg inside one of the ovaries starts to mature so that the cycle can begin again. The first day of menstrual bleeding marks the end of one cycle and the start of a new one. For this reason scientists refer to the first day of menstrual bleeding as day 1 of the menstrual cycle. Menstruation continues for approximately five days. The new egg continues to mature in the ovary during this time. When menstruation is completed the uterus begins to build up a new lining. The new lining is normally ready to receive a fertilised egg by day 14 of the menstrual cycle. During this time the egg continues to mature in the ovary. The egg is fully mature and ready to be released by day 14. The release of an egg from the ovary is called ovulation. The egg is released into the fallopian tube. If the egg is not fertilised it will pass out through the vagina during menstruation and the menstrual cycle will continue. If the egg is fertilised and the woman becomes pregnant her menstrual cycle will stop until after the baby is born.
Sexual 13.6 Sexual intercourse
intercourse results in the release of semen containing sperm into the vagina.
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Sexual intercourse occurs when the erect penis of the man is placed in the woman’s vagina. Movement of the penis in the vagina causes semen containing sperm to be released from the penis. The fertile period is the time during the menstrual cycle when sexual intercourse is most
