2.3 The Biology Of Controlling Fertility

Question 1

What is the difference between male and female fertility?

Answer 1

Males are continuously fertile but females are only fertile for a few days. Women are described as being cyclical fertile after ovulation

Question 2

What signs are shown that a woman is fertile?

Answer 2

• Temperature rises by 0.5*C due to the action of progesterone and remains elevated during the luteal phase
• Thinning of the mucus to allow sperm easy access to the female reproductive system

Question 3

What is stimulating ovulation?

Answer 3

• Ovulation is stimulated by drugs that mimic the action of FSH and LH
• Ovulation is stimulated by drugs that prevent the negative feedback effect of oestrogen on FSH secretion
• Used when women fail to ovulate or to collect ova for IVF

Question 4

What is artificial insemination?

Answer 4

• The insertion of semen into the female tract
• Used when a male has a low sperm count

Question 5

What is In Vitro Fertilisation?

Answer 5

• Eggs and sperm are removed and left to fertilise in culture dish
• Embryos are then implanted to uterus
• Used when woman has blocked oviducts

Question 6

What is Intra-Cytoplasmic Sperm Injection?

Answer 6

• Involves drawing a healthy sperm into a syringe needle and then injecting it directly into an egg to bring about fertilisation
• Commonly used as part of IVF treatment
• Used when defective sperm or very low in number

Question 7

What is Pre-Implantation Genetic Diagnosis?

Answer 7

Used in conjunction with IVF to identify single gene disorders and chromosomal abnormalities

Question 8

What are physical methods of contraception?

Answer 8

• Avoiding sexual intercourse during fertile periods
• Barrier methods physically block the ability of sperm to reach an ovum (condom, diaphragm, cervical cap)
• IUD alters cervical mucus and prevents implantation of fertilised eggs
• Sterilisation procedures in males involves a vasectomy
• Sterilisation procedures in females involves cutting and tying 2 oviducts to prevent eggs and sperm meeting

Question 9

What are oral contraceptive pills?

Answer 9

Oral contraceptive pills contain a combination of synthetic oestrogen and progesterone hormones that mimic negative feedback preventing the release of FSH/LH therefore preventing the development and maturation of a follicle

Question 10

What are progesterone only pills?

Answer 10

Also known as mini pills work by causing thickening of cervical mucus reducing the sperms access to the uterus

Question 11

What are morning after pills?

Answer 11

Emergency contraceptive pills that are taken after intercourse and prevent ovulation or prevent implantation of a fertilised egg