The biology of controlling fertility Flashcards
Describe the fertility of men:
men show continuous fertility, they produce sperm from the onset of puberty.
Describe the fertility of women:
Women show cyclic fertility, they are only fertile for a few days during each menstrual cycle.
How can you tell a women is ovulating?
The body temperature usually rises by around 0.5oC and the cervical mucus becomes thin and watery.
When is artificial insemination used?
Its used if the male has a low sperm count or if the male is sterile, a donor can be used to provide semen.
Describe the process of AI:
Several semen samples are collected over a period of time and injected directly into the uterus
When is Intra-cytoplasmic sperm injection used?
when the sperm are defective or are very low in numbers.
Describe the process of ICSI:
the head of the sperm is drawn into a needle and injected directly into the egg to achieve fertilisation.
When is in vitro fertilisation used?
It can be used in conjunction with pre-implantation genetic diagnosis to identify single gene and chromosome abnormalities.
Describe the process of IVF:
Eggs are surgically removed from the ovaries after hormone stimulation. Eggs are mixed with sperm in a culture dish and the zygotes are incubated until they have formed at least eight cells and are then transferred to the uterus for implantation.
What is an inter-uterine device?
Its a small T-shaped plastic and copper device that releases copper into the uterus.
How does the inter-uterine device prevent fertilisation?
The copper alters the cervical mucus making the sperm unable to swim to the egg and it prevents a fertilised egg from implanting in the uterus.
What is a vasectomy and what does it do?
It occurs in males, its a small incision and the vas deferent is cut and cauterised to prevent the sperm from travelling and being ejaculated.
What is tubal ligations and what does it do?
It occurs in females, the oviducts are cut and clipped to prevent the ova from reaching the uterus and prevent sperm from reaching the ova.
What is the contraceptive pill?
Its a chemical method of contraception.
How does the contraceptive pill work?
It contains a combination of synthetic oestrogen and progesterone that mimics negative feedback preventing the release of FSH and LH from the pituitary gland. Prevents the development of any follicle
