Science
(a) Name three techniques/devices used by human females to avoid pregnancy. Mention the side effects caused by each.
(b) What will happen if in a human female
- fertilisation takes place,
- an egg is not fertilised?
Answer
(a) Three techniques/devices used by human females to avoid pregnancy and their side effects :
1. Oral contraceptive pills :
- Function : These pills contain hormones that prevent ovulation (release of the egg).
- Side effects : May cause nausea, weight gain, mood changes and irregular menstrual cycles.
2. Copper-T :
- Function : A small device inserted into the uterus that prevents the fertilised egg from implanting in the uterine wall.
- Side effects : Can cause abdominal pain, excessive menstrual bleeding and risk of infection.
3. Surgical method (Tubectomy):
- Function : The fallopian tubes are cut and tied to prevent the egg from reaching the uterus.
- Side effects : May cause pain, infection or complications related to surgery; it is a permanent method.
(b) What happens if:
If fertilisation takes place then the zygote formed in the oviduct undergoes repeated cell divisions, travels to the uterus, and implants in the uterine wall. It develops into an embryo and later a foetus, resulting in pregnancy.
If the egg is not fertilised then the unfertilised egg, along with the thickened uterine lining, is shed out of the body through the vagina in the form of menstrual bleeding, called menstruation.
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