the biology of controlling fertility 2.3

Question 1

what is a fertile period

Answer 1

when a male is capable of gathering a child or when a female is capable of conceiving and becoming pregnant

Question 2

the 2 types of fertility males and females show

Answer 2

males show continuous and females show cyclical

Question 3

identification of a fertile period in females

Answer 3

rise is body temperature of 0.5° or the cervical mucus becomes thin and watery

Question 4

what increases the risk of infertility

Answer 4

age, genetics, disease, anorexia, obesity, drug misuse, smoking, stress, and poor diet

Question 5

the risks of infertility can cause

Answer 5

failure to ovulate, failure of implantation, blockage of oviducts and low sperm count

Question 6

stimulating ovulation

Answer 6

-ovulation stimulatory drugs can be used to treat infertility caused by a failure to ovulate
-one type of drug prevents the negative feedback effect of oestrogen of FSH secretion, this means more FSH is released which stimulates follicular development
-other types of drugs mimic the action of FSH and LH, these drugs can cause super ovulating that can result in multiple births or be used to collect ova for IVF programmes

Question 7

artificial insemination

Answer 7

-several samples of semen are collected over a period of time and inserted into the female reproductive tract when she is fertile
-this is particularly useful where the male has a low sperm count or if he is sterile a donor may be used to provide semen

Question 8

in vitro fertilisation

Answer 8

-IVF can be used to treat blockage of oviduct

1) surgical removal of eggs from ovaries after hormone stimulation
2) eggs are mixed with sperm in a culture dish
3) the fertilised eggs (zygotes) are incubated until they have formed at least 8 eggs
4) suitable embryos are the transferred to the uterus from implantation

Question 9

intracytoplasmic sperm injection

Answer 9

-if mature sperm are defective or very low in number, ICSI can be used
-the head of the sorry is drawn into a needle and injected directly into the egg to achieve fertilisation

Question 10

preimplantation genetic diagnosis

Answer 10

-during IVF and ICSI, cells are removed from the embryos to identify single gene disorders and chromosomal abnormalities
-only the most suitable embryos are transferred into the uterus from implantation

Question 11

what is contraception

Answer 11

the intentional prevention of pregnancy by natural or artificial methods which can be physical or chemical

Question 12

physical methods of contraception

Answer 12

avoiding fertile periods, barrier methods, intra uterine device (IUD) and sterilisation

Question 13

avoiding fertile periods

Answer 13

avoiding having sexual intercourse during fertile periods

Question 14

barrier methods

Answer 14

condoms, diaphragms and cervical caps work by preventing sperm from entering the uterus and reaching the ovum

Question 15

intra uterine device (IUD)

Answer 15

-a small structure that is often T shaped with metallic copper parts
-fitted into uterus to prevent implantation of an embryo in the endometrium

Question 16

sterilisation

Answer 16

usually irreversible and includes vasectomy’s in males (cutting and closing of sperm tubes) and tubal ligation in females (cutting or closing each oviduct)

Question 17

chemical methods of contraception

Answer 17

oral contraception pill/oestrogen and progesterone pill, progesterone only pill and morning after pill

Question 18

oral contraception pill/oestrogen and progesterone pill

Answer 18

contains a combination of synthetic oestrogen and progesterone that mimics the negative feedback effect preventing the release of FSH and LH from the pituitary gland

Question 19

progesterone only pill

Answer 19

causes thickening of the cervical mucus

Question 20

morning after pill

Answer 20

prevents ovulation or implantation