Hormones in human reproduction

Question 1

What do sex hormones cause during puberty?

Answer 1

they cause secondary sexual characteristics to develop

Question 2

What happens to girls during puberty?

Answer 2

At puberty, eggs begin to mature and one is released approximately every 28 days. This is called ovulation.

Question 3

What is oestrogen

Answer 3

Oestrogen is the main female reproductive hormone produced in the ovary.

Question 4

What is testosterone?

Answer 4

Testosterone is the main male reproductive hormone produced by the testes and it stimulates sperm production.

Question 5

What are the several hormones involved in the menstrual cycle of a woman?

(In order of when they are released in the cycle)

Answer 5

1) Follicle-stimulating hormone (FSH)
2) Oestrogen
3) Luteinising hormone (LH) stimulates the release of the egg.
4) progesterone

Question 6

What does Follicle-stimulating hormone (FSH) do?

what is it secreted by?

Answer 6

the first part of the cycle

causes maturation of an egg in the ovary.

stimulates the ovaries to produce oestrogen

secreted by the pituitary gland

Question 7

What does Luteinising hormone (LH) do?

what is it secreted by?

Answer 7

stimulates the release of the egg. (ovulation)

secreted by the pituitary gland

Question 8

What does oestrogen do?

what is it secreted by?

Answer 8

causing the lining of the uterus to grow

inhibits FSH release

stimulates LH release

secreted by ovaries

Question 9

What does progesterone do?

what is it secreted by?

Answer 9

• maintains the lining of the uterus during the second half of the cycle
• inhibits both FSH and LH release as progesterone stimulates the production of thick mucus which prevents any sperm getting through and reaching the eff
• secreted by empty follicle in ovaries

Question 10

What are the hormonal methods of contraception?

Answer 10

• oral contraceptives that contain oestrogen and progesterone to inhibit FSH production so that no eggs mature
• injection, implant or skin patch of slow-release progesterone to inhibit the maturation and release of eggs for a number of months or years
• intrauterine devices which prevent the implantation of an embryo or release a hormone

Question 11

What are the non-hormonal methods of contraception?

Answer 11

barrier methods such as condoms and diaphragms which prevent the sperm reaching an egg

• spermicidal agents which kill or disable sperm
• abstaining from intercourse when an egg may be in the oviduct
• surgical methods of male and female sterilisation.

Question 12

How do people increase fertility to give birth the natural way?

Answer 12

giving FSH and LH in a ‘fertility drug’ to a woman. She may then become pregnant in the normal way.

Question 13

Describe In Vitro Fertilisation process

Answer 13

• IVF involves giving a mother FSH and LH to stimulate the maturation of several eggs.
• The eggs are collected from the mother and fertilised by sperm from the father in the laboratory.
• The fertilised eggs develop into embryos.
• At the stage when they are tiny balls of cells, one or two embryos are inserted into the mother’s uterus (womb).

Question 14

Describe what Intra-cytoplasmic Sperm Injection (ICSI)

Answer 14

sperm is injected directly into an egg

useful if the man has a low sperm count

Question 15

What are the cons of a fertility drug?

Answer 15

• doesn’t always work and can end up being expensive if done too many times
• too many eggs could be stimulated resulting in unexpected multiple pregnancies

Question 16

What are the cons of a IVF?

Answer 16

• it is very emotionally and physically stressful
• the success rates are not high
• it can lead to multiple births which are a risk to both the babies and the mother.
• unused embryos in IVF are eventually destroyed = unethical
• genetic testing of embryos before implantation also raises ethical issues as it could lead to the selection of preferred characteristics