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The endocrine system

Animal coordination, control and homeostasis · Hormones and the endocrine system · note 1 of 3

Spec 7.1Download these notes (PDF)4 pages

The endocrine systemSpec 7.1

Hormones are chemical messengers. They are made in endocrine glands and released straight into the blood. The blood plasma carries them around the whole body, but each hormone only affects its target organs.

  1. An endocrine gland secretes a hormone into the blood.
  2. The blood carries the hormone around the body.
  3. The hormone reaches its target organ and causes a response.
Endocrine glands you need to know
GlandWhere it isHormone made
Pituitary glandAt the base of the brainReleases hormones that control other glands and organs
Thyroid glandIn the neckThyroxine
PancreasIn the abdomen, below the stomachInsulin
Adrenal glandsOne on top of each kidneyAdrenalin
OvariesIn the lower abdomen of a femaleOestrogen and progesterone
TestesIn the scrotum of a maleTestosterone
Higher tier
  • The pituitary gland releases FSH and LH, which act on the ovaries, and TSH, which acts on the thyroid gland.
  • The pancreas also makes a second hormone, glucagon.
Female and male body outlines showing the pituitary gland, thyroid gland, pancreas, adrenal glands on top of the kidneys, ovaries and testes, each labelled with the hormone it makes.Tap to enlarge
The endocrine glands and the main hormone each one makes.