endocrine system

• group of secretory cells surrounded by network of capillaries
• capillaries to bloodstream, then carried to target tissue and organs
• slower than autonomic nervous system
• endcorine gland releases a hormone

  • arrives at target cell
  • binds to specific receptor
  • influences chemicals or metabolic reactions inside the cell
• negative feedback - outside normal range hormone is released
• positive feedback - amplification of a stimulus causes more hormones to be released
• anterior pituitary gland

  • blood transports releasing inhibitory hormones
  • influences secretion of other hormones
  • stimulate or inhibit secretion
• posterior pituitary gland

  • formed from nervous tissue and consists of nerve cells
  • hormones synthesised in nerve cell bodies transported along axons, stored in vesicles
  • nerve impulses from hypothalamus trigger vesicles to release hormone into bloodstream
• parathyroid - controls amount of calcium in the body - vital for bone development
• pancreas - produces insulin to control blood sugar levels. glucagon and other hormones
• thyroid - produces hormones associated with calorie burning. controls metabolism
• adrenal - produces hormones controlling sex drive and cortisol promotes cardiovascular function and helps respond to stress
• pineal - found in brain, produces melatonin
• ovaries - secrete oestrogen, testosterone and progesterone
• testes - produces testosterone and sperm