Human Endocrine System (AQA GCSE Biology): Revision Note

Endocrine system structure & function

• The human endocrine system is composed of glands which secrete hormones directly into the bloodstream

• The blood carries the hormones around the body, where they affect target cells/organs

• Important structures in the endocrine system include the:

  • pituitary gland: a ‘master gland’ making hormones such as FSH and LH

  • pancreas: produces insulin which regulates the blood glucose level

  • thyroid: produces thyroxine which controls metabolic rate and affects growth

  • adrenal glands: produce adrenaline

  • ovaries (females): produce oestrogen

  • testes (males): produce testosterone

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Pituitary gland

• The pituitary gland in the brain is a ‘master gland’ which secretes several hormones into the blood in response to body conditions

• These hormones in turn act on other glands to stimulate the release of other hormones

  • E.g. the pituitary gland secretes the hormone FSH, which stimulates the release of oestrogen from the ovaries