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SAI International School
                                             Subject- Biology, Class-VII
                                       Chapter- Respiration in Organisms
                                    Subtopic- Respiration in Human Beings
                                                       Module- 13
                                                     Lesson Notes

               RESPIRATION IN HUMAN BEINGS


               In humans, respiration takes place through a complex system of organs. These organs
               collectively make the respiratory system.

               RESPIRATORY SYSTEM





























               The organs of human respiratory system


               Nostril and nasal cavity

                     The  nostril-These  are  the  external  openings  to  let  the  air  enter  into  the  nasal
                       cavity.
                     Nasal cavity-The inhaled air moves to nasal cavity through nostril.
                     Function  of  hair  present  in  nostril  and  nasal  cavity-It  traps  any  dust  particle
                       present in the inhaled air.
                     Function of mucus present in nasal cavity-It is a slimy substance which helps in
                       moistening the air and trapping germs.
                     The blood circulating through the nose warms the inhaled air .This clean, moist
                       and warm air then passes through nasal cavity.




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