Flashcards in The Biology Of Fertility Control Deck (26):
How fertile are men?
Men are continuously fertile
Why are men continuously fertile?
Due to relatively constant levels of pituitary hormones
How fertile are women?
Females fertility is cyclical usually restricted to 1-2 days immediately following ovulation
When are females most likely to conceive?
In a fertile period which is approximately six days around the time of ovulation
How can the time of ovulation be estimated?
• by the number of days after menstruation
• slight rise in body temperature on the day of ovulation
• the thinning of cervical mucus
How does female infertility happen?
Due to Failure to ovulate
How can female infertility be treated?
With drugs which mimic FSH and LH
What can these drugs cause?
(drugs which mimic FSH and LH)
• super ovulation
What can super ovulation result in?
• multiple births
• used to collect ova for in vitro fertilisation (IVF) programmes
What else can drugs be given for?
Given to prevent the negative feedback effect of oestrogen on FSH secretion
What is artificial insemination useful for?
If the male has a Low sperm count
• several samples of sperm are collected over a period of time
If a partner is sterile what can be used?
What is in vitro fertilisation (IVF)?
•Is when ova are surgically removed from the ovaries after stimulation by hormones
• ova are then mixed with sperm in a culture dish
• fertilised eggs are incubated until they have formed at least 8 cells and are then transferred to the uterus for implantation .
What does artificial insemination involve?
•Collecting several samples of semen over a period of time.
•It is useful if the male has a low sperm count
How can intracytoplasmic sperm injection (ICSI) used during ?
•IVF if mature sperm are defective or low in number
•The head of the sperm is drawn into a needle and injected directly into the egg to achieve fertilisation
What is pre-implantation genetic screening (PGS) used for?
To check embryos for single gen disorders and chromosomal abnormalities
What is pre-implantation genetic diagnosis(PGD) used for?
Used to check for a known chromosomal or gene defect
Why do people support PGD and PGA?
Offers reassurance to couples who are at a high risk of having a child with a genetic disease
Some of these people would choose to remain childless without the help of PGA and PGD
What is a great benefit to society as a whole?
A reduced frequency of genetic diseases and disorders
Why do people oppose to PGS and PGA ?
It is morally wrong to interfere with conception
They argue that these procedures are the start of eugenics-selective breeding in humans and lead to designer babies
What physical methods of contraception are there?
•avoiding fertile periods
What are barrier methods ?
They use a device to physically block the ability of sperm to reach the ova
Give examples of barrier methods
Intrauterine device (IUD)
What are chemical contraceptives based on?
Based on combinations of synthetic hormones that mimic negative feedback preventing the release of FSH/LH
What does the morning-after pill do?