human endocrine system

• the human body has two communication systems - the nervous system and the endocrine system
• the endocrine system sends hormones (chemical messengers) around the body and when they reach the target tissue they produce a response
• the endocrine system is made up of the glands which secrete hormones directly into the bloodstream
• pituitary gland:

  • master gland
  • secretes several hormones into the blood in response to body conditions
  • these hormones in turn act on other glands to stimulate other hormones to be released to bring about effects
• pancreas:

  • releases insulin and glucagon hormone to control blood glucose levels
• adrenal gland:

  • secretes adrenaline hormone which is involved in the 'fight-or-flight' response
• ovary:

  • secretes oestrogen and progesterone
  • involved in the menstrual cycle and the development of female secondary sex characteristics (characteristics that develop in puberty that distinguish a male and female)
• testes:

  • secretes testosterone
  • involved in the production of sperm and the development of male secondary sex characteristics
• thyroid:

  • secretes thyroxine
  • which controls metabolic rate, and growth
• nervous vs endocrine:

  • nervous is electrical impulses, endocrine is chemical messengers (hormones)
  • nervous can involve glands and muscles, endocrine only involves glands
  • nervous is faster than endocrine
  • response from endocrine is more long lived than nervous
  • nervous system uses electrical impulses which travel via neurones, but endocrine system uses hormones which travel in the blood
  • nervous system response acts in a precise area, endocrine system response acts in a general area