B10 Nervous system and homeostasis

• Function of nervous system?

  Enable organism to react to surroundings AND coordinates behaviour
• Two main parts of central nervous system?

  brain AND spinal cord
• What makes reflex actions rapid and automatic?

  Do not involve conscious part of brain
• Pathway of nervous response

  $stimulus \rightarrow receptor \rightarrow coordinator \rightarrow effector \rightarrow response$
• stimulus?

  change in internal or external environment
• synapse?

  junction between two neurons where chemicals are released, allowing electrical impulses to cross
• function of neurones?

  carry electrical impulses around the body
• homeostasis? The ability of an organism or system to maintain a stable internal environment despite external changes.
• why is homeostasis important?

  maintains optimal conditions for cell and organ function and enzyme activity
• Three internal conditions controlled in homeostasis

  1. body temperature 2. blood glucose concentration 3. water levels
• Three things all control systems include

  1. receptors
  2. coordination centres
  3. effectors
• Three coordination centres are:

  brain

  spinal cord

  pancreas
• two examples of effectors

  1. muscles
  2. glands