Flashcards in Key Area 2.3 - The Biology of Controlling Fertility Deck (16):
Describe the difference in fertility between men and woman.
Men - constantly fertile due to relatively constant levels of pituitary hormones.
Women - fertility is cyclical and the most fertile period is from a few days before until 1-2 days after ovulation.
What can the time of ovulation be estimated by?
- The number of days after menstruation
- a slight rise in body temperature on the day of ovulation
- thinning of cervical mucus
What can female infertility be due to?
Failure to ovulate which is usually the result of a hormone imbalance.
What can be used to stimulate ovulation?
Ovulatory or fertility drugs
What do some ovulatory drugs prevent?
The negative feedback effect of oestrogen on FSH secretion.
What can ovulatory drugs cause?
Super ovulation, which can result in multiple births.
How are ovulatory drugs and IVF related?
The drugs can be used to collect ova for in vitro fertilisation programmes.
What is artificial insemination?
- A treatment in which semen is inserted into the female reproductive tract without intercourse having taken place.
- It is useful when the male has a low sperm count.
- Involved collecting and combining several samples of semen over a period of time.
- If the male partner is infertile sperm from a donor may be used.
What is IVF?
- Involves the surgical removal of eggs from ovaries after hormone stimulation, mixing with sworn to achieve fertilisation, incubation of the zygotes and uterine implantation.
What can be used during IVF treatment?
• ICSI if mature sperm are defective or very low in number
- It involves the head of a sperm being drawn into a needle and injected directly into the egg to achieve fertilisation.
• PGD is used to identify single gene disorders and chromosome abnormalities.
How do methods of contraception work?
By preventing fertilisation or implantation.
What is contraception?
The intentional prevention of pregnancy by natural or artificial methods.
Name the physical methods of contraception.
- Barrier methods
- Avoiding fertile periods
- Intra-uterine devices
- Sterilisation procedures
What are chemical contraceptives based on?
Combinations of synthetic progesterone and oestrogen that mimic negative feedback, preventing the release of FSH/LH, inhibiting follicular development, ovulation and implantation, or causing thickening of the cervical mucus.
Name some economic issues with the use of fertility drugs.
- Should unlimited treatment be available on the NHS?
- Should health insurance companies be obliged to cover infertility treatment?
- Could the medical resources be better allocated elsewhere?