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Waterworks (Urinary system)

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					Urinary system

Waterworks
Your body gets rid of waste                             Blood flows in and
                                                         out of the kidneys
chemicals and excess water by                          through large blood
                                                                    vessels.

making urine. Urine comes from
two organs called kidneys. They
filter and clean blood as it flows
through, removing chemicals
that your body doesn’t need.
                                                                                       Kidney

            The kidneys
            clean your blood.




                                                                                          Your kidneys act
                                                                                          like sieves, filtering
                                                                                          unwanted substances from
                                                                                          your blood and turning
                                                                                          them into urine.




                                                                       Urine dribbles away
                                                                       through a tube called
                                                                       the ureter.




              The ureters          Urinary system
              carry away
              urine.                 Your kidneys, bladder,
                                     and the tubes connected
                                      to them make up your
                  The bladder
                  stores urine.
                                      urinary system. The last                       If you put your hands
                                                                                     on your hips and your
                                      part of the urinary system                     thumbs on your back,
                                      is the urethra. Urine comes                    your kidneys are next
                                                                                       to your thumb tips.
                                      out of this tube when you
                                      go to the toilet.

                                  The urethra gets
                                  rid of urine.
90
       How long do your kidneys take to clean all the blood in your body?
                                                                                                   Waterworks
Inside a kidney                                                                                   Balancing act
                                                                                                  Your kidneys keep
The blood vessels entering your kidneys                                                           the water level in
divide into smaller and smaller branches.                                                         your body perfectly
These lead to a million tiny filtering units                                                      balanced. If you
 called nephrons.                                                                                 drink too much,
                                                                                                  your kidneys make
                                                     Blood flows                                  watery urine to get
                                                     through a knot of
                                                     tiny vessels.
                                                                                                  rid of any excess.
                                                                                                  When your body
                                                                                                  is short of water,
                                                            Fluid passes out
                                                            into a chamber.                       your kidneys pass
                                                                                                  less into your urine.

                                                                                                           When the water
                                                                                                           level is low, the
                                                                                                           pituitary gland
                                                                        This part of the brain
                                                                                                           releases the
                                                                        monitors the water
                                                                                                           hormone ADH.
                                                 The fluid leaves       level in blood.
                                                 through this
                                                 tube.

       Inside a nephron
       As blood flows through a nephron, fluids
       leave the blood vessel and pass to a long,
       looped tube. Useful chemicals are then
       reabsorbed into blood.

Water disposal
                                            A low water
Here’s how your body                  level also triggers
                                     a feeling of thirst,
gets rid of water.                   making you drink.

                                                                                    ADH travels
       Urine makes up more                                                          to your
       than half of the water                                                       kidneys in
       that leaves your body.                                                       your blood.
                                    Water
       Breath contains over         control
       a quarter of the water
       your body gets rid of.       Your kidneys work
                                    together with your brain
       Sweat is only about one      to control your water
       twelfth of the water         level. When this level
       leaving your body.           is low, your brain                             Your kidneys save
                                    releases a hormone that                        water, making your
       Poo is fairly dry and                                                       urine stronger.
       contains only a little bit   makes your kidneys
       of your liquid waste.        save water.
                                    About 25 minutes.                                                                     91

				
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posted:10/10/2012
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