The endocrine system

• The endocrine system is made up of glands that secrete chemicals called hormones directly into the bloodstream. 
• The blood carries the hormone to its target organ where it produces an effect.
• The endocrine system is made up of glands that secrete chemicals called hormones directly into the bloodstream. 
• The blood carries the hormone to its target organ where it produces an effect.
• The target organ has receptors on the cell membranes that pick up the hormone molecules, triggering a response in the cell.
• Many processes in your body are coordinated by these hormones
• Hormones can act very rapidly but, compared to the nervous system, many hormonal effects are slower but longer lasting
• Hormones that give a rapid response include insulin, which controls your blood glucose, and adrenaline, which prepares your body for fight or flight
• Slow-acting hormones with long-term effects include growth hormones and sex hormones.
• The pituitary gland is a “master gland”
• It secretes several hormones into the blood which act on other glands
• These other glands then release their own hormones to bring about effects
• ADH which controls the volume of urine produced
• FSH which stimulates eggs to mature in the ovaries and stimulates the ovaries to produce oestrogen
• TSH which stimulates the thyroid gland to produce thyroxine, which helps control metabolism