The nervous system

sense organs detect stimuli
1. eyes, ears, tongue, nose and skin are sense organs
  1. all of these contain different receptors, these receptors are a group of cells that are sensitive to a certain stimulus
    1. they chang the stimulus energy(E.G light energy) into electrical impulses
      1. examples of stimulus: light, sound, pressure, touch, pain or temperature
        light receptor cells are like most animal cells
Central Nervous system coordinates a response to detected stimulus
1. CNS is sent all information from sense organs
  1. from which reflexes and actions are coordinated
    1. CNS is the brain and spinal cord ONLY
      1. instructions from the CNS are sent to the effectors which respond accordingly
        This can be a reflex for example, reflexes help prevent injury as its an automatic response
        Passage of information in a reflex is called a reflex arc.
  2. neurones(nerve cells) transmit information quickly as electrical impulses to and from the CNS
    1. The impulses movement
      1. receptors in sense organs: detect stimuli
        sensory neurones: nerve cells that carry signals as electrical impulses from receptor in sense organs to CNS
        synapse
        relay neurone: nerve cells that carry signals from sensory neurones to motor neurones
        synapse
        Motor neurones: nerve cells that carry signals from the CNS to the effector muscles or glands
        glands respond by secreting(releasing) chemical substances
        synapses connect neurones. the nerve signal arrives as electrical impulses then the signal is transferred by chemicals which diffuse across the gap, these chemicals then set off a new electrical charge in the next neurone

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The nervous system

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	Erstellt von Jack Willepotte vor etwa 8 Jahre