IB Biology topic 6.6

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6.6.1 Draw and label diagrams of the adult male and female reproductive systems.
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6.6.2 Outline the role of hormones in the menstrual cycle, including FSH (follicle stimulating hormone), LH (luteinizing hormone), estrogen and progesterone.
FSH and LH (pituitary gland) - affect processes in the ovary. FSH stimulates development of follicles (fluid filled sacs that contain an egg cell). LH stimulates follicles to mature and release their eggs and the development of corpus luteum.
Estrogen and Progesterone (the ovary) - stimulates the development of female secondary sexual characteristics during puberty + development of the uterus lining that is needed during pregnancy.
6.6.3 Annotate a graph showing hormone levels in the menstrual cycle, illustrating the relationship between changes in hormone levels and ovulation, menstruation and thickening of the endometrium.
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6.6.4 List three roles of testosterone in males.
Testosterone (in the testes):
(1) causes male genitalia, including a penis, to develop in the fetus.
(2) causes male secondary sexual characteristics to develop during puberty.
(3) testosterone maintains the sex drive encouraging men to sexual intercourse and thereby pass on their genes to offspring.
Also one of the hormones needed to stimulate sperm production by the testes.
6.6.5 Outline the process of in vitro fertilization (IVF).
In vitro fertilisation can help childless couples getting pregnant.
(1) Drug injected once a day, three weeks, to stop menstrual cycle.
(2) Large doses of FSH injected to stimulate the ovaries to develop many follicles.
(3) HCG (hormone) is injected 36 hours before egg collection - loosen egg in follicle and mature them.
(4) The man provides semen by ejaculating into a jar - healthiest ones are concentrated.
(5) Eggs are extracted from follicle.
(6) Eggs are mixed with sperm in a shallow dish.
(7) Dishes checked for successful fertilisation.
(8) 2-3 embryos selected and placed in the uterus.
(9) Pregnancy test and later scan to test the success of the IVF.
6.6.6 Discuss the ethical issues associated with IVF.
Arguments for IVF:
- Parents willing to go through the process of IVF have a strong desire to be parents and are likely to be very loving parents.
- Infertility brings great unhappiness to parents who want children - this source of unhappiness can be removed with IVF.
- Embryos killed during IVF cannot feel pain as their nervous system has not developed.

Arguments agains IVF:
- Inherited forms of infertility may be passed on to children = the suffering of the parents are repeated in the offspring.
- More embryos are sometimes produced than needed and the spare are killed: this deny them of a chance to live.
- IVF is an unnatural process carried out in laboratories; in contrast to natural conception which is a results of love.
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