B5 - Growing Up Flashcards
What happens to males during puberty?
• The voice breaks (deepens).
• Hair grows on the face and body.
• The body becomes more muscular.
• Genitals develop.
• The testes start making sperm.
What happens to females during puberty?
• The breasts develop.
• Pubic hair and hair under the arms grows.
• The hips widen.
• Periods start (menstruation) and eggs mature.
Describe the hormones in the menstrual cycle and what they do.
- The pituitary gland in the brain releases a hormone called FSH.
- FSH causes an egg in one of the ovaries to mature.
- It also stimulates the ovaries to make the hormone oestrogen.
- Oestrogen stimulates the pituitary gland to release another hormone, LH.
- LH triggers the release of the egg (ovulation) from the ovary.
- Oestrogen also inhibits further production of FSH and it repairs the uterus lining (the endometrium, which is the innermost layer of the uterus wall).
- Progesterone maintains the uterus lining and inhibits LH.
What is conception and what is a period?
Conception happens if a sperm meets the egg and fertilises it. If the egg is not fertilised, at the end of the cycle the uterus lining passes out of the body. This is the period. If the egg is fertilised then the uterus lining stays so that the fetus can develop.
What hormones are high during pregnancy ?
Both oestrogen and progesterone levels are high and they inhibit FSH and LH production from the pituitary gland. This prevents the development and release of any more eggs.
What hormones are used in contraceptive pills?
Scientists realised that if women took oestrogen and progesterone in a daily pill, the high levels in the body would mimic pregnancy and prevent ovulation. Without ovulation you cannot become pregnant.
Contraceptive pills contain a lower dose of oestrogen and some progesterone, or just progesterone. These give fewer side-effects.
What are some causes of infertility ?
• blocked fallopian tubes or sperm ducts
• eggs do not develop or are not released from ovaries
• the testes do not produce enough sperms.
Describe the process of IVF.
• The woman is injected with FSH, which stimulates her ovaries to produce eggs.
• The eggs are then collected from the woman and mixed with the man’s sperm in a glass dish.
• To make the procedure more likely to work, healthy sperms are selected and one is injected into each egg.
• The fertilised eggs begin to develop into embryos.
• When they are tiny balls of cells, two are chosen and inserted into the woman’s uterus.
What is artificial insemination and when is it used?
If the male’s sperm count is low, sperm can be donated from another male and inserted into the woman’s vagina. Also used for single women or lesbian couples who wish to become pregnant.
What is egg donation and when is it used?
A woman may donate some of her eggs to another woman who cannot make eggs. Women undergoing IVF often donate ‘spare eggs’.
What is surrogacy and when is it used?
If a woman has had her uterus removed, another woman (the surrogate mother) may have the rst woman’s embryo (the result of IVF) implanted in her uterus. After the birth the surrogate mother gives the baby back to its biological mother.
What are ovary transplants and when is it used?
So far only a few ovary transplants have been carried out, with the donor being the identical twin of the recipient. This could restore the fertility of women who undergo early menopause and are no longer fertile, or who have had radiation treatment for cancer. A woman could have her ovaries removed before being treated for cancer, have them frozen and have them transplanted back after the treatment.
What are the disadvantages to fertility treatment?
These treatments are very expensive and there is no guarantee they will work. All medical procedures carry some risk.
How can you check for Down Syndrome?
Down’s syndrome is caused by the presence of an extra chromosome. To check for Down’s syndrome, doctors can insert a needle into the uterus and take some amniotic fluid containing fetal cells. This procedure is called amniocentesis. The cells are grown in a lab so that they divide. Their chromosomes can be observed under a microscope and counted.
