ATS GCSE Biology - Lungs and gaseous exchange Key words

• air breathed out

  nitrogen ~80%oxygen ~16%carbon dioxide ~4%

  
• air breathed in

  nitrogen ~80%oxygen ~20%carbon dioxide 0.04%

  
• exhalation


  intercostal muscles and diaphragm relax= smaller volume = higher pressue = air pushed out of lungsbreathing out

  
• inhalation


  intercostal muscles and diaphragm contract = increased volume = lower pressure= air enters lungsbreathing in

  
• diaphragm


  strong sheet of muscle separates upper from lower bodycontract = inhalation = flattensRelax = exhalation = moves up, domed

  
• intercostal muscles

  contract = inhalation = breath in = ribs move up and outrelax = exhalation = breath out = ribs move down and in

  
• alveoli gas exchange

  oxygen from alveoli into red blood cells carbon dioxide out of blood plasma into alveoli

  
• capillary network


  surrounds the alveoli for gas exchange

  
• steep concentration gradient

  maintained by blood flowing away from alveoli area

  
• alveoli


  air sacs for gas exchange- large surface area- rich blood supply - maintains concentration gradient - moist- thin (short diffusion path)

  
• bronchi


  the main tubes one going to each lung left and right bronchi (plural)bronchus (single)left bronchus = Right hand side of diagramright bronchus = Left hand side of diagram

  
• trachea


  windpipe connects mouth and nose to bronchi

  
• abdomen

  lower body separated from thorax by the diaphragm

  
• thorax


  chest upper body

  
• ventilation


  the process of getting air into and out of the lungs

  
• rib cage


  protects lungsimportant in ventilation of the lungs

  
• respiratory system


  be able to label the structures