click below
click below
Normal Size Small Size show me how
IGCSE Biology 15.5~
BISVietnam IGCSE Biology 15.5~15.9
Question | Answer |
---|---|
Why is Ante-natal care important? | Vital for the health of the fetus-mother needs to provide the right nutrition and protection for the fetus. |
Why is calcium needed? | The mother having enough carbohydrates, iron, protein and calcium in her diet. |
Why is iron needed? | The mother and the baby needs iron to make more haemoglobin so oxygen can be carried to the developing fetus. |
Why is carbohydrate needed? | So that the pregnant mother has enough energy to mover her heavier body around. |
Why is protein needed? | The egg dies and passes out of the vagina and the yellow body breaks down and is lost during menstruation. The cycle starts again. |
Why shouldn't the mother smoke when pregnant? | Nicotine and carbon monoxide cross the plaenta and can result in premature or underweight babies. |
Menopause | Between the ages of 45-55 years a woman's period stops as her menstrual cycle have stopped. |
Why shouldn't the mother drink alcohol when pregnant? | Alcohol can cross the placenta and can cause a variety of effects such as birth defects and mental retardation. |
Follicle Stimulating Hormone (FSH) | Starts the cycle by stimulating a follicle to develop. The egg cell starts to divide and increase in size. Cells start to secrete oestrogen into the bloodstream. |
Why shouldn't the mother take drugs when pregnant? | Drugs can cross the placenta so some babies are born with an addiction to the drug. |
Oestrogen | Causes the lining of the uterus to thick in preparation to receive fertilised egg and prevents any more eggs developing. Passes to the pituitary gland in the blood and stops it from making any more FSH. |
Stimulated by oestrogen. Travels to the ovary in the blood, stimulating ovulation and remaining follicle cells to form a yellow body. | |
What happens in labor? | Oxytocin is released to stimulate the muscles of the uterus to contract which become stronger & more frequent. The opening of the cervix stretches & amnion breaks-amniotic fluid escapes. The cervix dilates & the baby's head is pushed through the vagina. |
What happens at birth? | The baby passes out of the vagina and takes its first breath. The umbilical cord is tied and cut. The placenta detaches from the uterus and passes out as the afterbirth. |
Progesterone | Produced by the yellow body. Makes the uterus lining thicken even more and prevents it breaking down. |
Passive Immunity | The child has the mother's antibodies in the blood, but is unavle to produce them itself. |
Ovulation | When follicle bursts releasing the egg, some follicle cells and the fluid into the oviduct |
Advantages of breast milk | Breastfed children are less likely to develop certain diseases such as childhood cancers and diabetes. Mothers are less likely to develop cancers of breast, womb and ovaries. |
When does menstruation start? | Girls in puberty-12 to 18 years old |
What happens during a menstrual cycle? | A follicle develops inside the ovary and the lining of the uterus thickens. If implantation does not occur, the lining of uterus and vagina breaks down. The cycle starts again. |
Puberty in boys | Testes make testosterone which stimulates: the growth of the male sex organs, the testes to make sperm cells, growth of hair on the face, the deepening of the voice, development of muscles in the body. |
Puberty in girls | Ovaries make oestrogen which stimulates: the growth of the female sex organs, the start of the first menstrual cycle and the first period, growth of hair on parts of the body, grwoth and development of breasts, widening of hips |
Fertility drugs in women | Injections containing FSH to stimulate the release of eggs and increase the chances of preganancy. Tablets that make the pituitary insensitive to oestrogen. |
Fertility drugs in men | Artificial insemination (AI) where donor sperm are used to fertilise a women's fertile eggs. |
Intra-Uterine Device (IUD) | Small plastic device wrapped in copper or contains hormones. Fitted inside uterus-prevents sperm passing through the uterus, embryo from implanting in uterus. Some contain progesterone-causes mucus in cervix to become sticky&thick-sperm can't swim. |
Cap or Diaphragm | Rubber dome. Woman places it over cervix before intercourse. Prevents the man's sperm from entering the uterus. Should be used with sperm-killing cream or foam. |
Condom | Thin rubber tube rolled over the man's erect penis before intercourse. Stops sperm from entering the woman's body. Protection against STDs. Most commone form of birth control, easy to use. |
Femidom | Femal equivalent of a condom and is inserted into the vagina. |
The pill | Oral contaceptive taken by mouth. Contain oestrogen and progesterone in varying concentrations. The woman has to take the pill every day. Reliable, convenient method fo contraception. Side effects-sore breasts, weight gain, depression, painful periods. |
Spermicides | Chemicals that kill sperm. Sold as foam, cream or jelly. Woman puts the cream into her vagina before intercourse. Not effective-should be used with another method-cap or condom. |
Rhythm Method | Relies on determining when ovulation is most likely to occur and abstaining from sex in the days before and just after that date. |
Vasectomy | Operation to cut the sperm duct. THe operation is not usually reversible. |
Sterilisation | Irreversible operation where oviducts are cut and blocked. |
Vasectomy | Operation to cut the sperm duct. THe operation is not usually reversible. |
Sterilisation | Irreversible operation where oviducts are cut and blocked. |
Human Immunodeficiency Virus (HIV) | Infects cells in the immune system. Transmitted in the semen or in the blood. With time HIV infection may lead to a collection of diseases which is known as AIDS. |
HIV and Lymphocytes | HIV destroys T lymphocytes leading to a weakining of the immune system. This makes people susceptible to many diseases, such as TB. |
Acquired Immunodeficiency Syndrome (AIDS) | HIV infection may lead to the development of AIDS. Early symptoms are very much like flu, swollen glands, high temperature. Later, weight loss, various types of cancer and a decrease in brain function. |
How is HIV transmitted? | The virus can pass from one person to another during unprotected sex. By hypodermic needles contaminated with infected blood-HIV spread quicly amongst drug users. Unborn babies-pass through placenta, breast milk, at birth. |
Prevention of HIV | The use of condoms during sexual intercourse, free needle exchange schemes to reduce the use of shared needles amongst drug users, careful screening of donated blood for transfusions. |
Gonorrhoea | Bacterial disease which is spread during sexual intrecourse with an infected partner. It can be prevemted by having just one uninfected partner or by using condoms. Its spread is controlled by tracing and treating any sexual contacts of an infected person |