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Network of nerves (Brain and senses)

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                                                                                                                                                                                                                 Brain
                                                               Network of nerves




                                                                                                                                                                                                                  and
                                                               All of the body contains nerve cells. These




                                                                                                                                                                                                                 senses
                                                               link up to form the network of nerves
                                                               we call the nervous system. It            Brain

                                                               transports messages between                                                                 A good night’s sleep
     Which is the longest nerve in your body?




                                                                                                                                                           Your body and brain slow down when
                                                               the body and the brain.                                                                     you sleep, but they don’t stop working.
                                                                                                                                                           Your brain needs sleep to sort out the
                                                                                                                                                           events of the previous day.
                                                               Quick as a flash
                                                                                                                                                                                   Your knee jumps
                                                               Nerve cells lie next to one                                                               Cross your                forwards even
                                                                                                                                                         legs and tap              though your brain
                                                               another forming long chains.                                                              just below the            hasn’t
                                                                                                                                                         knee.                     told it to move.
                                                               They pass messages to their
                                                               neighbours – rather like a                                   Spinal cord –
                                                               speedy relay race – to and                                   the centre of
                                                                                                                            the network
                                                               from the brain.
                                                                                        Brain cells viewed
                                                                                        through a
                                                                                        microscope.




                                                                                                                                                                    No need to think
                                                                                                                                                                    You do some things without
                                                                                                                                                                    needing to think about them.
                                                                                                                                                                    These are called reflex actions
                                                                                                                                                                     and include blinking, coughing,
                                                                                                                                                                      and the knee-jerk reflex.




                                                               Messages
                                                               Your brain
                                                               controls your body.
                                                               It receives messages
                                                               from all parts of
                                                                                                                                                 ain.
The one running from your big toe to the base of your spine.




                                                               your body and
                                                                                                                  travel fas than a high-speed tr




                                                               decides what
                                                               to do.                                                                                                                            Pain-killers
                                                                                                                                                                                      When you get a filling,
                                                                      Walking is the result of                                                                                       the dentist gives you an
                                                                      your brain telling your                                                           You’ve got 150,000 km          anaesthetic. This drug
                                                                      leg muscles to move.                                                              (93,200 miles) of nerves
                                                                                                                                                        in your body.                    stops nerves passing
                                                                                                                                                                                        on pain messages for
                                                                      Hunger is your stomach                                                                                                     a short time.
                                                                      telling your brain that it’s
                                                                      empty and you must eat.

                                                                      Needing to urinate is
                                                                      a response to the message
                                                                                                                            t er




                                                                      that your bladder is full.

                                                                      Itching is an irritating
                                                                      feeling. Your body reacts
                                                                      by making you scratch.
                                                                                                                                                                                                                 Network of nerves




                                                                      Pain gets a very quick
                                                                      response. You move away
                                                                                                         Messages




                                                                      from what’s hurting you.

                                                                      Blinking happens
                                                                      without you needing                                                               Pins and needles
                                                                      to think about it.
                                                                                                                                                        Sitting cross-legged for a long time
                                                                      Breathing is automatic
                                                                                                                                                        squashes the nerves in your legs. When
                                                                      too. It carries on even                                                           you stand up, the nerves start to work
                                                                      when you are asleep.                                                               again, producing a tingling feeling.
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