Unit 2: Physiology and Health - Key Area 3: The Biology of Controlling Fertility

Question 1

When are males fertile an why is this?

Answer 1

Male are constantly fertile due to a constant level of pituitary hormones. This results in a fairly steady concentration of testosterone being secreted and sperm being produced.

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. The time of ovulation can be estimated by the number of days after menstruation, a slight rise in body temperature on the day of ovulation and the viscosity of the cervical mucus. Hormone levels can also be indicators.

Question 4

How can a woman be infertile due to hormones?

Answer 4

A woman be infertile due to a failure to ovulate because she is not producing enough of the hormones FSH (folllicle stimulating hormone) or LH (luteinising hormone)

Question 5

How can a woman how is infertile due to a failure to ovulate due to not producing enough FSH and LH be treated?

Answer 5

Ovulation can be successfully stimulated by drugs that contain hormones that can:

• Replicate/mimic FSH and LH.
• Stop the negative feedback of oestrogen into not producing FSH.

Question 6

What can drugs that stimulate ovulation in infertile woman cause?

Answer 6

These drugs can cause super ovulation resulting in multiple births or the production 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 some 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 his partner’s reproductive tract at the time when she is 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 doing drawn up in to a very fine needle and injecting it directly into an egg to bring about 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 blockage of the oviduct.

Question 16

What does ‘ in vitro ‘ stand for?

Answer 16

Fertilisation outside of the body, in a culture dish.

Question 17

What are the steps involved in IVF?

Answer 17

1) The woman is given hormonal treatment to stimulate multiple ovulation.
2) Eggs are surgically removed from the ovary.
3) The removed eggs are mixed with sperm in a culture dish of nutrient medium to allow fertilisation to occur.
4) The fertilised eggs (zygotes) are incubated in the nutrient medium to allow cell division to occur.
5) Once each embryo is composed of at least 8 cells, 2 or 3 are chosen to be inserted into the mother’s uterus where they will hopefully implant.
6) Pre-implantation genetic diagnosis (PGD) can be used in conjunction with IVF to identify single gene disorders and chromosomal abnormalities.
7) The remaining embryos can be frozen in case another attempt is needed.

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

IVF

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

ICSI

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.

Question 23

What does the oral contraceptive pill/ combined pill contain and what does it do to prevent pregnancy ?

Answer 23

The oral contraceptive/combined pill is a chemical method of contraception. It contains a combination of synthetic oestrogen and progesterone that mimics negative feedback preventing the release of FSH and LH from the pituitary gland.

Question 24

What does the progesterone only/mini pill do to prevent pregnancy?

Answer 24

The progesterone-only (mini) pill causes thickening of the cervical mucus.

Question 25

What does the morning-after/emergency contraceptive pill do to prevent pregnancy?

Answer 25

The morning-after/ emergency pill prevents ovulation or implantation.