Unit 2: Physiology & Health - Key Area 3: The Biology of Controlling Fertility Flashcards
When are males fertile an why is this?
Males are constantly fertile due to a constant level of pituitary hormones.
When are females fertile and why is this?
Female fertility is cyclical, with the fertile period being 1-2 days following ovulation.
What can be used to measure a females fertile period?
Indicators like temperature and cervical mucus can be used. The time of ovulation can be estimated by the number of days after menstruation, a slight rise in body temperature on the day of ovulation and the viscosity of the cervical mucus. Hormone levels can also be indicators.
How can a woman be infertile due to hormones?
A woman be infertile due to a failure to ovulate because she is not producing enough of the hormones FSH (folllicle stimulating hormone) or LH (luteinising hormone)
How can a woman how is infertile due to a failure to ovulate due to not producing enough FSH and LH be treated?
Ovulation can be successfully stimulated by drugs that contain hormones that can:
- Replicate/mimic FSH and LH.
- Stop the negative feedback of oestrogen into not producing FSH.
What can drugs that stimulate ovulation in infertile woman cause?
These drugs can cause super ovulation resulting in multiple births or the production many eggs for use in ovulation.
What is artificial insemination?
Artificial insemination is the insertion of semen into the female reproductive tract by some means other than sexual intercourse.
What can artificial insemination be used to treat?
Artificial insemination can be used to treat infertility in men if the man has a low sperm count.
What is the process of artificial insemination?
Several samples of the mans sperm can be collected over a period of time and frozen until needed. They are then defrosted and released into his partner’s reproductive tract at the time when she is likely to be most fertile.
How can artificial insemination be used if a man is completely infertile?
A sperm donor can be used with the same process.
What does ICSI stand for?
Intra-cytoplasmic sperm injection.
What can ICSI be used to treat?
ICSI can be used to treat fertility in a man if the mans sperm count is low, or if his mature sperm are defective in some way.
What does ICSI involve?
ICSI involves the head of a sperm doing drawn up in to a very fine needle and injecting it directly into an egg to bring about fertilisation.
What does IVF stand for?
In vitro fertilisation
What fertility issues is IVF used for?
Possible reasons for infertility could include blockage of the oviduct.
What does ‘in vitro’ mean?
Fertilisation ‘outside of the body’.
What are the steps involved in IVF?
1) The woman is given hormonal treatment to stimulate multiple ovulation.
2) Eggs are surgically removed from the ovary.
3) The removed eggs are mixed with sperm in a culture dish of nutrient medium to allow fertilisation to occur.
4) The fertilised eggs (zygotes) are incubated in the nutrient medium to allow cell division to occur.
5) Once each embryo is composed of at least 8 cells, 2 or 3 are chosen to be inserted into the mother’s uterus where they will hopefully implant.
6) Pre-implantation genetic diagnosis (PGD) can be used in conjunction with IVF to identify single gene disorders and chromosomal abnormalities.
7) The remaining embryos can be frozen in case another attempt is needed.
What are possible treatment methods that can be used to treat a failure to ovulate?
Drugs that prevent the negative feedback effect of oestrogen on FSH secretion or ovulatory drugs that can mimic the action of FSH.
What are possible treatment methods that can be used to treat blocked oviducts?
IVF
What are possible treatment methods that can be used to treat low sperm count?
Artificial insemination.
What are possible treatment methods that can be used to treat mature sperm defection?
ICSI
In what way is fertility in men different from fertility in women?
Men are constantly fertile whereas women are cyclically fertile.
What does the oral contraceptive pill/ combined pill contain and what does it do to prevent pregnancy?
The oral contraceptive/combined pill is a chemical method of contraception. It contains synthetic oestrogen and progesterone that mimics negative feedback preventing the release of FSH and LH.
What does the progesterone only/mini pill do to prevent pregnancy?
The progesterone-only (mini) pill causes thickening of the cervical mucus.
