Investigation Of Reproduction And Development In Animals :: essays research papers fc

Investigation of Reproduction and Development in Animals Cycles, Conception and Contraception Fertility is the condition of being fertile. The aim of contraception is to inhibit fertility in individuals, hence, slowing population growth. The system by which all female contraception must operate: the menstrual cycle. What is the menstrual cycle? and what hormones are involved in controlling it? After puberty, the female produces an egg each month. Other changes take place on a cyclic basis including the uterus lining and hormone levels. These changes are called the menstrual cycle. Follicle stimulating hormone (FSH) from the pituitary gland stimulates the growth of follicles in the ovary. Follicles produce oestrogen that stimulates the pituitary to produce leutinising hormone (LH). As LH increases the size of the follicle increases until an egg is released. The corpus luteum formed in the follicle secretes progesterone that prepares the lining of the uterus for pregnancy. If fertilisation does not occur the lining of the uterus is discharged from the body in the process called menstruation. What is the birth control pill? The combined oral contraceptive pill (the pill) is a reversable, hormonal method of birth control. The pill consists of a mixture of two synthetic hormones similar to oestrogen and progesterone, the woman’s natural hormones which regulate the menstrual cycle. The pill is on of the most popular methods of birth control. How does it work? The pill basically prevents ovulation, therefore, the ovaries can’t release a mature egg. Without an egg for the sperm to fertilize , a woman cannot get pregnant . The hormones also increase cervical mucus, making it difficult for sperm to pass into the uterus. How effective is the pill? If used correctly, the pill is highly effective. It has a less than one percent failure rate. However, because many people misuse it, the actual failure rate is more like three percent. The pill does not provide protection against sexually transmitted diseases. How are pills used? One pill must be swallowed at the same time every day. It is not any single pill, but the day-to-day process of taking the pill which provides protection against pregnancy. What is infertility? Infertility in humans and other species(animals) is the inability to concieve or carry a pregnancy to a live birth. The causes of infertility can be identified in some cases. The majority of cases relate to female factors (50%), 40% relate to male factors and 10% aree unknown. Infertility sometimes may serve as a combination of both male and female factors. If the cause of infertility is known, treatment of some kind may be available. In other cases a problem may disappear on its own and fertility is restored.