Unit 2: The biology of controlling fertility

Question 1

When are the males fertile and why is this?

Answer 1

In men fertility is continuous. Levels of testosterone, FSH and ICSH are kept relatively constant through negative feedback. As a result sperm are produced continually.

Question 2

When are females fertile and why is this?

Answer 2

Female fertility is cyclical, with the fertile period being 1-2 days following ovulation

Question 3

What can be used to measure a females fertile period?

Answer 3

Indicators like temperature and cervical mucus can be used. A slight rise in body temperature by 0.5 degrees and the viscosity of the cervical mucus (becomes thin and watery giving sperm easy access)

Question 4

How can a women be infertile due to hormones?

Answer 4

A women can be infertile due to a failure to ovulate because she is not producing enough of the hormones FSH and LH.

Question 5

How can a women who is infertile due to failure of ovulation by not producing enough FSH or LH be treated?

Answer 5

Ovulation can be successfully stimulated by drugs that contain hormones which can mimic the action of FSH and LH and drugs that can stop the negative feedback of oestrogen on FSH secretion.

Question 6

What can drugs that stimulate ovulation in infertile women cause?

Answer 6

These drugs can cause super ovulation, resulting in multiple births or the production of many eggs for use in ovulation.

Question 7

What is artificial insemination?

Answer 7

Artificial insemination is the insertion of semen into the female reproductive tract by means other than sexual intercourse.

Question 8

What can artificial insemination be used to treat?

Answer 8

Artificial insemination can be used to treat infertility in men if the man has a low sperm count.

Question 9

What is the process of artificial insemination?

Answer 9

Several samples of the mans sperm can be collected over a period of time and frozen until needed. They are then defrosted and released into the female reproductive tract at the time when she is most likely to be most fertile.

Question 10

How can artificial insemination be used if a man is completely infertile?

Answer 10

A sperm donor can be used with the same process.

Question 11

What does ICSI stand for?

Answer 11

Intra-cytoplasmic sperm injection.

Question 12

What can ICSI be used to treat?

Answer 12

ICSI can be used to treat fertility in a man if the mans sperm count is low, or if his mature sperm are defective in some way.

Question 13

What does ICSI involve?

Answer 13

ICSI involves the head of a sperm being drawn up into a needle to be injected directly into an egg to achieve fertilisation.

Question 14

What does IVF stand for?

Answer 14

In vitro fertilisation.

Question 15

What fertility issues is IVF used for?

Answer 15

Possible reasons for infertility could include the blockage of a woman’s oviduct.

Question 16

What does ‘ in vitro’ stand for?

Answer 16

it stands for fertilisation outside of the body, in a culture dish.

Question 17

What are the steps involved in IVF?

Answer 17

1) The women is given FSH and LH to stimulate the maturation of several eggs in the ovary.
2) The eggs are collected from the women and fertilised by sperm from the man in a culture dish in the laboratory.
3) The fertilised eggs are incubated until they develop into embryos.
4) At the stage when they are tiny balls of at least eight cells, one or two embryos are inserted into the woman’s uterus (womb).

Question 18

What are possible treatment methods that can be used to treat a failure to ovulate?

Answer 18

Drugs that prevent the negative feedback effect of oestrogen on FSH secretion or ovulatory drugs that can mimic the action of FSH.

Question 19

What are possible treatment methods that can be used to treat blocked oviducts?

Answer 19

In vitro fertilisation.

Question 20

What are possible treatment methods that can be used to treat low sperm count?

Answer 20

Artificial insemination.

Question 21

What are possible treatment methods that can be used to treat mature sperm defection?

Answer 21

Intra-cytoplasm sperm injection.

Question 22

In what way is fertility in men different from fertility in women?

Answer 22

Men are constantly fertile whereas women are cyclically fertile.