Nervous system and endocrine system

• central nervous system


  consists of The brain and the spinal chord and is the origin of all complex commands and decisions
• nervous system 


  consists of the central nervous system and the peripheral nervous system
• peripheral nervous system


  sends information to the central nervous system from the outside world, and transmits messages from the CNS to muscles and glands in the body
• somatic nervous system 


  transmits information fron receptor cells in the sense organs to the central nervous system. it also recieves information from the CNS that directs muscles to act
• autonomic nervous system 


  transmits information to and from internal bodily organs. it is 'autonomic' as the system operates involuntarily. it has 2 main divisions: the sympathetic and parasympathetic nervous systems
• specialised network (NS)


  • to collect, process and respond to information in the environment
  • to co-ordinate the working of different organs and cells in the body
• cerebral cortex 


  • highly developed in humans and is what distinguishes our higher mental functions from animals
• spinal chord 


  • extention of the brain, it is responsible for reflex actions such as pulling your hand away from a hot plate
• endocrine system


  one of the body's major information systems that instructs glands to release hormones directly into the bloodstream. these hormones are carried towards target organs in the body
• gland 


  an organ in the body that synthesises substances such as hormones.
• hormones 


  chemical substances that circulate in the bloodstream and only affect target organs. they are produced in large quantities and dissapear quickly. their effects are very powerful
• fight or flight 


  the way an animal responds when stressed. the body becomes physiologically aroused in readiness to fight an agressor or, in some cases, flee
• adrenaline 


  a hormone produced by the adrenal glands which is part of the human bodys immediate stress response system. adrenaline has a strong effect on the cells as part of the cardiovascular system - stimulating the heart rate, contracting blood vessels and dilating air passages
• main endocrine glands

  • adrenals
  • pancreas
  • ovaries (female)
  • testes (male)
  • hypothalamus
  • pituitary
  • thyroid
  • parathyroid
• the endocrine system works alongside the nervous system to control vital functions in the body.
• the endocrine system also works much slower than the nervous system but has widespread powerful effects.
• thyroxine - effects the heart and increases heart rate and metabolic rates, which then effects growth rates. produced by the thyroid gland
• pituitary gland - major gland in the endocrine system. located in the brain and controls the release of hormones from all the other endocrine glands in the body
• endocrine system and ANS


  when a stressor is perceived, the first thing that happens is the hypothalamus triggers activity in the sympathetic branch of the ANS. the ANS changes from its normal resting state (parasympathetic state) to the sympathetic state. adrenaline is then released and triggers psychological changes. this creates fight or flight.