Hormones 👩⚕️
- In I/GCSE Biology, many processes within the body are coordinated by chemical substances called hormones.
- Hormones are secreted by glands and are transported to their target organs by the bloodstream.
- Hormones regulate the functions of many organs and cells.
Hormones in the menstrual cycle
- FSH – follicle stimulating hormone
Secreted from：pituitary gland
Effects：egg matures in ovary and Release of oestrogen from ovary
Secreted from：ovaries
Effects：inhibits release of FSH and causes release of LH
- Oestrogen
Secreted from：ovaries
Effects：inhibits release of FSH and causes release of LH
- LH – luteinising hormone
Secreted from：pituitary gland
Effects：stimulates release of egg from ovary
Controlling Reproduction
Increasing fertility
FSH is given as a fertility drug to woman whose own level of FSH is too low to stimulate eggs to mature.
IVF – In Vitro Fertilisation🩺
- Fertility drugs are given to increase egg production.
- Eggs are removed and fertilised with sperm outside the body.
- These can be allowed to develop into embryos.
- They may be implanted back into the womb of the mother.
Benefits:
- Enables infertile couples to have children.
- Excess embryos can be used for research.
Concerns:
- Procedures are expensive.
- Health risks for the mother.
- Multiple births – some babies may die.
- People do not like embryos to be used for research.
Oral contraceptives 💊
Contain hormones that inhibit FSH production so that no eggs mature.
Benefits:
It can reduce population growth in the developed world.
Concerns:
- Health problems – eg some increase the risk of blood clots.
- Religious objections to preventing conception.
That's the end of the topic!
Drafted by Joey (Biology)
Reference:
https://getrevising.co.uk/resources/biology_revision_notes4