4.5 Hormones in human reproduction and contraception Flashcards
What is the menstrual cycle?
the monthly release of an egg from a woman’s ovaries
At puberty what sort of hormones begin to be produced?
sex hormones
Which hormone is produced in women in at puberty?
oestrogen is produced in the ovaries
Which hormone is produced in men in at puberty?
testosterone is produced in the testes
Oestrogen is involved in which cycle?
menstrual cycle
Testosterone causes which cell to be produced by the testes?
sperm
What happens in stage 1 of the menstrual cycle?
uterus lining breaks down for about 4 days
What happens in stage 2 of the menstrual cycle?
uterus lining builds up again (day 4-14)
What happens in stage 3 of the menstrual cycle?
an egg develops and is released at day 14
What happens in stage 4 of the menstrual cycle?
the uterus lining is maintained from day 14 to day 28
What is the release of an egg from the ovaries called?
ovulation
What happens after day 28 o the menstrual cycle if not egg is fertilised
stage 1 - uterus lining breaks down and comes out of the body (period)
FSH has two jobs, what are they?
- causes an egg to mature (in a follicle) in one of the ovaries
- causes the ovaries to produce oestrogen
Oestrogen has three jobs, what are they?
- causes the lining of the uterus to grow
- stimulates (causes) the release of LH from the pituitary gland
- inhibits (stops) production of FSH from the pituitary gland
LH has one jobs, what is it?
- stimulates (causes) the release of an egg form the ovary at day 14
Progesterone has two jobs, what are they?
- maintains the ulerus lining for the 2nd half of the cycle
- inhibits (stops) FSH and LH production
Where is FSH produced?
pituitary gland
Where is LH produced?
pituitary gland
Where is oestrogen produced?
ovaries
Where is progesterone produced?
in the ovaries by the remains of the follicle after egg release
How is pregnancy prevented if a man and woman have sex?
contraception
Why is oestrogen used in contraceptive methods?
it inhibits FHS so no eggs develop
Why is progesterone used in contraceptive methods?
it causes a thick mucus to prevent sperm reaching the egg
What sort of contraceptive is the combined contraceptive pill (with oestrogen and progesterone)?
Oral contraceptive
How effective is the pill as a contraceptive?
99%
What are the side effects of using the pill?
Headaches and nausea
Does the oral combined contraceptive pill protect against STI’s?
No
Why might some women take the progesterone only pill?
it has fewer side effects
Other than the pill, what other forms of contraception use hormones?
- contraceptive patch (oestrogen and progesterone), lasts 1 week
- implant (progesterone only), lasts 3 years
- injection (progesterone only), lasts 2-3 months
- intrauterine device (IUD) inserted into the uterus to kill sperm and prevent the egg from implanting
What are the two types of IUD?
- plastic - release progesterone
- copper - kill sperm
What form of barrier methods can be used as contraception?
male or female condoms
Do condoms prevent STI transmission during sex?
Yes
Where does a contraceptive diaphragm need to be positioned?
over the cervix (entrance to uterus)
What substance must be used with a diaphragm, or can be used on its own to kill sperm?
spermicide
How effective is using spermicide along as a contraceptive?
only 70-80%
What are the more ‘drastic’ methods of avoiding pregnancy?
- sterilisation (cutting or tieong the fallopian tubes or sperm ducts).
- Natural methods which involve timing when sex occurs with when it is unlikely there will be an egg (not very successful).
- abstinence (no sex)
