structures

• Nose

  Lining of nose and nasal cavity is convoluted and lined by mucous membranes which warms and humidifies air passing over membranes

  Hairs and mucus lines the nose trapping debris, stopping them reaching the lungs
• Nasal cavity

  Projections that increase internal surface area

  Smell receptors

  Hair and mucus
• Pharynx (throat)


  The throat; the pharynx joins the mouth cavity to the oesophagus and larynx

  Region from the nasal cavity to the top of the trachea and oesophagus
• Epiglottis 


  A cartilage flap at the base of the pharynx that covers the trachea during swallowing

  Flap of elastic cartilage
• Larynx (voice box) 


  The structure at the top of the trachea that contains the vocal cords

  Cartilage structure joining the pharynx to trachea
• Trachea (windpipe)


  The tube that takes air from the throat to the lungs; the windpipe

  Made of C-shaped cartilage rings which holds the structure open ensuring air can always pass through

  Trachea splits into two branches at the base with one taking air into each lung
• Bronchi


  C-shaped cartilage rings

  As bronchi get smaller, cartilage becomes more spread out with more smooth muscle and elastin

  Cilia and mucus
• Bronchioles


  A very small air tube in the lung

  Do not contain cartilage

  Made of smooth muscles and elastin 

  Cilia and mucus
• Lungs

  Left lung is divided into 2 lobes

  Right lungs is divided into 3 lobes
• Alveoli


  Air sacs in the lungs

  Smallest bronchioles open into cluster of tiny air sacs

  Wall is only one cell thick

  Surrounded by a network of blood capillaries
• Ribs


  The framework for the chest
• Intercostal muscles


  Muscles between ribs
• Diaphragm 


  Muscle that separates the chest from the abdomen