the biology of controlling fertility

Question 1

explain the differences between fertility in males and females

Answer 1

women have cyclical fertility while men have constant fertility

Question 2

how do you identify the fertile periods in women

Answer 2

from a 0.5 degrees increase in temperature and thinner cervical mucus

Question 3

name and explain some treatments for infertility

Answer 3

drugs to stimulate ovulation = preventing the negative feedback of oestrogen on FSCH secretion
artifical insemination = semen is collected and inserted into the females reproductive track
Intra-cytoplasmic sperm injection = the head of the sperm is drawn into a needle and injected into the egg
In vitro fertilisations + eggs are removed from the ovaries after hormone stimulation and mixed with sperm in a culture dish, then incubated before transferred to the uterus

Question 4

what is PGD used for

Answer 4

PGD (per-implantation genetic diagnosis) is used to identify single gene disorders and chromosomal disorders

Question 5

what are the physical methods of contraception

Answer 5

condoms/diaphragm/cervical cap = provides a physical barrier to prevent the sperm reaching the egg
intra-uterine device (IUD or coil) = small T shaped structure that is fitted into the uterus to prevent the implantation of an embryo
sterilisation = vasectomy in males and tubal ligation in females. prevents the release of gametes

Question 6

what are the chemical methods of contraception

Answer 6

contraceptive pill = contains synthetic estrogen and progesterone that mimic the negative feedback preventing the release of FSH and LH from the pituitary gland
progesterone only/mini pill = causes the thickening of the cervical mucus to prevent sperm entering