2.3 the biology of controlling fertility

Question 1

What type of fertility do men exhibit?

Answer 1

Continuous fertility

Men continually produce sperm in their testes.

Question 2

what type of fertility do females exhibit?

Answer 2

Cyclical fertility

Women are only fertile for a few days during each menstrual cycle.

Question 3

What physiological changes indicate a woman’s fertile period?

Answer 3

Body temperature rises and cervical mucus becomes thin and watery

Question 4

What are common causes of infertility in males?

Answer 4

• Low sperm count
• Abnormal sperm
• Low motility

Question 5

What are common causes of infertility in females?

Answer 5

• Failure to ovulate
• Blocked oviducts
• Implantation failure

Question 6

What is artificial insemination?

Answer 6

A procedure where several samples of semen are collected over time.

Question 7

When is artificial insemination particularly useful?

Answer 7

When the male has a low sperm count.

Question 8

What can be done if a partner is sterile in artificial insemination?

Answer 8

A donor may be used to provide semen.

Question 9

What is the role of drugs in stimulating ovulation?

Answer 9

They prevent the negative feedback effect of estrogen on FSH secretion.

Question 10

What is the result of stimulating ovulation with certain drugs?

Answer 10

Encouragement of more follicles to develop.

Question 11

What can other ovulatory drugs mimic?

Answer 11

The action of FSH and LH.

Question 12

What can super ovulation lead to?

Answer 12

Multiple births or collection of ova for IVF.

Question 13

What is the first step in IVF programmes?

Answer 13

Surgically removing eggs from ovaries after hormone stimulation.

Question 14

How are eggs fertilized in IVF?

Answer 14

They are mixed with sperm in a culture dish.

Question 15

What happens to fertilized eggs in IVF before implantation?

Answer 15

They are incubated until they have formed at least eight cells.

Question 16

What is pre-implantation genetic diagnosis (PGD)?

Answer 16

A technique used in IVF to identify single gene disorders and chromosomal abnormalities.

Question 17

What is intra-cytoplasmic sperm injection (ICSI)?

Answer 17

A procedure where the head of the sperm is injected directly into the egg.

Question 18

When is ICSI used?

Answer 18

If mature sperm are defective or very low in number.

Question 19

what are physical methods of contraception

Answer 19

• barrier methods (e.g. condoms, diaphragm prevent fertilization)
• insta uterine devices (IUDs that prevent implantation of blastocyst)
• sterilization
  (•In females, oviducts are blocked or sealed preventing the ova from reaching the sperm
  • In males, duct from testicles are cut preventing the release of sperm)

Question 20

what are chemical methods of contraception

Answer 20

-The oral contraceptive pill
(It contains a combination of synthetic ostrogen and progesterone that mimics negative feedback preventing the release of FSH and LH from the pituitary gland
This prevents the development of follicles)
• The progesterone-only (mini) pill (causes thickening of the cervical mucus)
• The morning-after pill (prevents ovulation or implantation)