The endocrine system
The endocrine system is made of glands that secrete
chemicals called hormones directly into the bloodstream
The blood carries the hormone to a target organ , where it produces
an effect
Compared with the nervous system, hormonal effects are slower but
act for longer
The pituitary gland in the brain is the master gland : it
secretes several hormones in response to body conditions, and these act on
other glands to stimulate the release of other hormones
Gland
Hormone(s)
Effect
Pituitary (base of the brain)FSH, LH, ADH, growth hormone
controls other glands; water balance; growth
Thyroid (neck)thyroxine controls metabolic rate; growth and development
Adrenal glands (on top of the kidneys)adrenaline fight or flight response
Pancreas (below the stomach)insulin , (HT) glucagon control of blood glucose
Ovaries oestrogen , progesteronefemale sex characteristics; menstrual cycle
Testes testosterone male sex characteristics; sperm production
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The endocrine glands pituitary gland the master gland — it releases hormones that control other glands thyroid makes THYROXINE, which controls the base rate of metabolism adrenal glands make ADRENALINE, for 'fight or flight' pancreas makes INSULIN and GLUCAGON, which control blood glucose ovaries make OESTROGEN (females) testes make TESTOSTERONE (males) The endocrine system uses hormones — chemicals carried in the blood. Compared with the nervous system it is slower to act, but the effects last much longer and are more general. Outline of the human body with the pituitary, thyroid, adrenal glands, pancreas, ovaries and testes marked and labelled
Nervous system
Endocrine system
Signal electrical impulses
chemical hormones
Carried by neurones
the blood
Speed very fast
slower
Duration short
longer lasting
Target precise: one muscle or gland
general: all cells with receptors for the hormone
Two differences the exam expects: hormones are slower and act for
longer ; nerves use electrical impulses , hormones are
chemicals in the blood
Name the hormone when the question asks for one: thyroxine, not
"thyroid". And spell glucagon and glycogen correctly; a
hybrid of the two scores nothing
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In the full topic
• The endocrine system• Control of blood glucose• DiabetesRead the free biology topics →