Physiology and Health: The Biology of Controlling Fertility Flashcards
Infertility treatments and contraception are based on what?
The biology of fertility
Men continually produce sperm in their testes showing what?
Continuous fertility
Why do men show continuous fertility?
Due to relatively constant levels of pituitary hormones
When are women fertile?
For a few days during each menstrual cycle
Women show what leading to a fertile period?
Cyclical fertility
The time with the highest likelihood of pregnancy resulting from sexual intercourse is from when to when?
From a few days before until one to two days after ovulation
Time of ovulation can be based on what?
A slight rise in body temperature on the day of ovulation and the thinning of cervical mucus
What are the evident changes in body temperature and cervical mucus after ovulation?
Body temperature rises by around 0.5 degrees Celsius and cervical mucus becomes thin and watery
Female infertility may be due to failure to ovulate, which is usually the result of what?
A hormone imbalance
Ovulatory or fertility drugs can be used to do what?
Stimulate ovulation
Some ovulatory drugs work by preventing what?
The negative feedback effect of oestrogen on FSH secretion
Other ovulatory drugs do what?
Mimic the action of FSH and LH
These ovulatory drugs can cause super ovulation which can result in or be used for what?
Multiple births.
Or can be used to collect ova for in vitro fertilisation (IVF) programmes
What is artificial insemination (AI)?
A treatment in which semen is inserted into the female reproductive tract without intercourse having taken place
When is AI particularly useful?
When the male has a low sperm count
During AI, several samples of semen are what over a period of time?
Collected and combined
If a male partner is infertile (sterile) who can be used to provide semen for AI?
A donor
What does IVF involve?
The surgical removal of eggs from ovaries after hormone stimulation, mixing with sperm to achieve fertilisation, incubation of zygotes and uterine implantation
What is IVF used in conjunction with?
Pre-implantation genetic diagnosis (PGD) to identify single gene disorders and chromosomal abnormalities
In IVF eggs are mixed with what in a culture dish?
Sperm
The fertilised eggs are incubated until when and then what happens to them?
They have formed at least eight cells and are then transferred to the uterus for implantation
What can be used if mature sperm are defective or very low in number?
Intracytoplasmic Sperm Injection (ICSI)
What does ICSI involve?
The head of a sperm being drawn into a needle and injected directly into the egg to achieve fertilisation
What is contraception and what type of methods are used?
The intentional prevention of pregnancy (contraception) by natural or artificial methods.
Physical and chemical methods.
Physical methods of contraception have a biological basis and include what?
Barrier methods such as intra-uterine devices and sterilisation procedures
What is a chemical method of contraception?
The oral contraceptive pill
What does the contraceptive pill contain?
A combination of synthetic oestrogen and progesterone that mimics negative feedback, preventing the release of FSH and LH from the pituitary gland
What does the progesterone-only (mini) pill cause?
Thickening of the cervical mucus preventing the entry of sperm and fertilisation
What does the morning-after pill do?
Prevents ovulation or implantation
