U2 KA3 - The Biology Of Controlling Fertility Flashcards
In what ways can a Women’s fertile period be identified
- Timing of menstrual cycle Ovulation is the release of atypically occurs 10 to 16 days before the start of a period.
- Temperature – monitored using a thermometer
Temperature increases by 0.2 – 0.5C approximately 1 day after ovulation and remains high during the luteal phase (14 days)
Fertile for 1-3 days after this rise in temperature.
* Cervical Mucus High levels of oestrogen prior ovulation stimulates the cervix to produce a watery mucus
Mucus may become clearer, wetter and less viscous around ovulation.
Becomes less viscous during fertile period making it easier for sperm to swim through
Therefore increases chances of fertilisation
What are some treatments of Infertility
- Stimulating Ovulation
- Artificial Insemination
- IVF
- ICSI
Describe Stimulating ovulation
Women may fail to ovulate due to underlying factors such a failure of the pituitary gland to secrete adequate FSH or LH.
Ovulation in these circumstances can be successfully stimulated through hormone treatment. These drugs work by:
- Mimicking the normal action of FSH and LH
- Prevent the negative feedback effect of oestrogen on FSH secretion
Preventing the negative feedback effect of oestrogen on FSH secretion results in more oestrogen therefore more FSH leading to multiple ovulation in a single cycle.
These drugs can occasionally becomes so effective that it can results n super-ovulation leading to multiple births at one time
Describe Artificial insemination
Artificial insemination is the introduction of semen into the female reproductive tract.
This would normally happen if a man has a low sperm count.
Several samples of sperm are provided by the male over a period of time and frozen until required.
They are defrosted and released into the females cervical region (via tube delivery) when he is likely to be most fertile
Donor sperm may also be used as an alternative
Describe In Vitro Fertilisation
- Woman given hormonal treatment to stimulate multiple ovulation
- A surgical procedure removes several eggs from the ovary
- Egg cells are mixed with sperm to allow fertilisation (in a nutrient culture)
- Fertilised eggs are incubated to form embryos (PGD is performed)
- Embryos are into the mothers uterus
- Remaining embryos are frozen for other attempts
Describe PGD
Pre-implantation genetic diagnosis (PGD) is carried out to identify single gene disorders and chromosomal abnormalities.
This test allows experts to select which embryos should be implanted
Describe Intercytoplasmic Sperm Injection
If a mans sperm count is low or defective Intracytoplasmic sperm injection is used.
This involves injecting a healthy sperm head directly into the egg cell to initiate fertilisation.
ICSI is commonly used during IVF treatment
Give 3 examples of Physical contraceptives
- Barrier Methods
- Inter-Uterine Devices
- Sterilisation Procedure
Give 3 examples of Chemical contraceptives
- Pills (Combination of hormones)
- Morning-after Pills
- Mini Pills
Discuss IUD’s, its advantages and its disadvantages
A T-shaped structure that is inserted through cervix and placed in uterus. It can last many months or even years
Advantages
*Requires no daily attention
*Immediately effective (99.2-99.9%)
Disadvantages
*No protection against STIs
*Requires clinic visits
*Can cause very difficult menstruation
*Possible risk to future fertility
Discuss Sterilisation procedures, its advantages and its disadvantages
Male vasectomy – sperm ducts are cut so sperm cannot mix with semen and be released.
Female – Cut fallopian tubes – still get ovulation but eggs are reabsorbed by the body
Advantages
* Permanent contraception
* Immediately effective (in females)
* No daily attention
Disadvantages
* No protection against STIs
* Requires surgery – risk
* Not reversible
* Not immediately effective (in males)
Describe Pills (combination of hormones)
Hormonal methods of contraception involve synthetic progesterone combined with synthetic oestrogen
Taking a pill every day without fail for 3 weeks from the final day of the previous menstrual period results in
*Increase in concentration of progesterone and oestrogen in bloodstream
*induce negative feedback, preventing the release of FSH/LH.
*Ovulation fails to occur
Dummy (placebo) pills are usually taken during fourth week to allow the levels of oestrogen and progesterone to drop to allow menstruation
Describe Morning-after pill
“Morning after” pills are emergency hormonal contraception pills taken to prevent implantation.
They contain higher doses of progesterone and oestrogen than normal oral contraceptive pills in
