Contraception and Treating Infertility Flashcards
What is contraception
contraception is the control of fertility to prevent pregnancy by preventing egg and sperm
meeting or preventing implantation of fertilised egg in uterus
How can fertility be controlled
Fertility can be controlled by a variety of hormonal and non-hormonal
methods of contraception.
Describe different methods of contraception
Using oral contraceptives such as the pill.
These contain hormones which prevent the body from producing the hormone FSH. FSH causes an egg to mature.
If a woman takes the contraceptive pill, then this prevents any eggs from maturing (therefore now pregancy)
(also stops uterus preparing for pregnancy/thickens cervical mucus )
(Pills contain oestrogen and some progesterone or just progesterone - they inhibit production and release of FSH)
Another hormonal form of contraception is to use an implant, a skin patch or an injection. These contain progesterone. The progesterone stops eggs from maturing or being released
Another form of contraception is to use a barrier method. These include a condom or a diaphragm. These prevent the sperm from reaching an egg
Many women use an intrauterine device or IUD. This is sometimes called the coil. These can prevent an embryo from implanting. Some coils also release hormones to reduce the chances of fertilisation
Some people choose surgical forms of contraception. This is called sterilisation. In the case of women, this prevents the egg from reaching the uterus. In this case of men, this prevents the sperm from leaving the penis.
This involves cutting or tying the fallopian tubes (which connect the ovaries to the uterus) in a female or the sperm duct (the tube between the testes and penis) in a male
The final form of contraception is abstaining from sexual intercourse during the time after ovulation. This is called a natural form of contraception
Advantage of the contraceptive pill
It is highly effective if it is taken correctly
Disadvantage of the contraceptive pill
It must be taken every day. If a women forgets to take it, then there is a risk of pregnancy
Certain contraceptive pills also have a risk of side-effects. These include an increased risk of breast cancer or blood clots. However these risks are small
Another disadvantage of both the pill and the other hormonal forms of contraception, is that none of these protect against sexually transmitted infections (STIs) e.g. HIV.
Advantage of using an implant, a skin patch or an injection which contain progesterone
They are more convenient than taking a daily pill.
The implant lasts for three years, the contraceptive injection lasts around thirteen weeks and the patch lasts around one week
Disadvantage of using an implant, a skin patch or an injection which contain progesterone
These hormonal forms of contraception can have side effects
Another disadvantage of both the pill and the other hormonal forms of contraception, is that none of these protect against sexually transmitted infections (STIs) e.g. HIV.
Advantage of using a barrier method
Barrier methods are an effective form of contraception if they are used correctly
One of the advantages of barrier methods is that because they do not use hormones, they do not have side effects
Condoms can also reduce the risk of STIs
Both condoms and a diaphragm are more effective if they are used with a spermicide gel. Spermicides kill or disable sperm and they reduce the chances of fertilisation
Disadvantage of using a barrier method
One disadvantage of condoms is that they can break or slip off
Advantage of using an Intrauterine device (IUD)
An IUD is highly effective and can prevent pregnancy for up to ten years
IUDs also have very few side effects
Disadvantage of using an Intrauterine device (IUD)
An IUD does not protect against sexually transmitted infections
Advantage of sterilisation (surgical forms of contraception)
Both forms of sterilisation (men and women) are highly effective.
Disadvantage of sterilisation (surgical forms of contraception)
However, they are very difficult to reverse, so a person has to be certain that they will never want children before going ahead
Surgical forms of contraception do not protect against STIs
There is a very small chance that the tubes can re-join.
Disadvantage of abstaining from sexual intercourse during the time after ovulation. This is called a natural form of contraception
The problem here is that it is very hard to tell when a woman has ovulated. So this makes natural forms of contraception difficult
Again this method of contraception does not protect against STIs
Explain why issues around contraception cannot be answered by science alone
Many people have strong opinions on contraception.
The Catholic church teaches that all contraception is unethical, apart from natural methods
Other people believe that it is a person’s right to choose whichever form of contraception is best for them
Many people point out that using condoms reduces the risk of sexually transmitted infections
Ultimately, the issues around contraception cannot be answered by science alone
Different types of treatment used to treat infertility
In one treatment, FSH and LH are given to a woman. This combination is called a fertility drug….
This includes giving FSH and LH in a ‘fertility drug’ to a woman
Another type of treatment is called in-vitro fertilisation or IVF
Describe how hormones are used to treat infertility
In one treatment, FSH and LH are given to a woman. This combination is called a fertility drug.
This includes giving FSH and LH in a ‘fertility drug’ to a woman
This causes the woman to ovulate more than usual
This increases her chances of becoming pregnant through sexual intercourse
Describe IVF
In this case, fertilisation takes place outside the body
During IVF, the mother is first treated with FSH and LH. This causes several eggs to mature
These eggs are then collected from the mother
At this point, sperm from the father is collected and it is used to fertilise the eggs in the laboratory
The fertilised eggs then develop into embryos
Once the embryos are tiny balls of cells, these are inserted into the mother’s uterus (womb)
These embryos can then develop inside the mother in the usual way
Benefit of IVF
It gives a woman the chance to have a baby of her own
Recent advances in microscope techniques heave helped to improve the techniques (and therefore have helped to improve the success of IVF)
Using microtools, it is possible to remove a cell from the embryo so that it can be genetically screened to check that it is healthy
Time-lapse imaging of the embryo in the incubator can be continuously monitored to help select the healthiest for implantation (those that are more likely to result in a successful pregnancy)
Describe the problems and issues around IVF
The success rates are not high
IVF is emotionally very stressful for both parents
It is also physically demanding on the mother e.g. in the treatment of fertility drugs and the collection of eggs
IVF can lead to multiple births. This is risky for both the babies and the mother
Not all the embryos that are created will be transferred into the mother. This means that many embryos are destroyed and some people find that unethical
IVF is also expensive. Some people think that this money could be spend on other medical issues for example treatments for cancer
Page 180 Question 3a
Describe what is happening in each diagram
Expt 1: Shoot has grown straight up. No change in auxin concentration
in shoot.
Expt 2: Shoot has grown straight up. No change in auxin concentration
in shoot.
Expt 3: Shoot has grown towards one-sided light. Increased auxin
concentration on unlit side.
Page 180 Question 3b
What does this demonstrate about phototropism
Phototropisms apply only to light-sensitive tip of shoot–
shoot with no tip showed no phototropic response as no hormonal impulse was generated and …. shoot with tip placed on impermeable block
showed no phototropic response as hormonal impulse could not penetrate block.
Phototropic response is result of growth lower down shoot–
shoot with tip placed on agar block grew towards light as hormonal impulse passed through agar block and auxin moved to unlit (darker) side of
shoot, stimulating cells there to grow more.
