nervous and endocrine system

• nervous system: specialised network of cells that is our primary internal communication system - based on electrical and chemical signals

  main functions:

  • to collect, process and respond to information
  • to co-ordinate the work of different organs and cells
• central nervous system: made up of brain and spinal chord

  • brain: centre of all conscious awareness - out layer (cerebral cortex) covers the brain like an orange peel

  highly developed in humans and is what distinguishes our mental functions

  • spinal chord: passes messages to and from the brain, connecting nerves to the PNS
  • also responsible for reflex actions - pulling hand away from a hot plate
• peripheral nervous system: transmits messages through millions of neurons to and from the central nervous system

  • autonomic nervous system (ANS) : governs vital functions in the body - breathing, heart ratre
  • somatic nervous system (SNS): governs muscle movement and receives information from sensory receptors
• endocrine system: controls vital functions in the body

  • thyroid gland: produces hormones that are secreted into the bloodstream and can affect any cell that has a receptor
  • thyroid gland produces thyroxine, affecting cells in the heart

  pituitary gland: 'master gland' as it controls the release of hormones from all other glands

  glands

  • adrenal
  • ovaries
  • testes
  • pancreas
• endocrine and autonomic work together during a stressful event.

  during event:

  • hypothalamus activates pituitary gland to trigger activity in sympathetic branch
  • this then changes the parasympathetic state to the sympathetic state
• adrenaline: stress hormone that is released into the bloodstream - triggers physiological changes in the body that create physiological arousal, ready for fight or flight
• parasympathetic action: once the threat has passed, the nervous system returns the body to its resting state

  • parasympathetic system acts as a 'brake' and reduces the activities of the body that were increased due to the threat