Chapter 4 Respiratory system

• structure of respiratory system allows


  efficient flow of air into lungs so that gas exchange can occur between air and blood
• organs of respiratory system

  nose, trachea, bronchi, two lungs
• air enters body through

  mouth and nose
• lining of nose and nasal cavity is lined by

  mucous membranes
• as air passes over membranes it is


  warmed and humidified
• hair and mucous lining in the nose trap

  debris, preventing from reaching the lungs
• pharynx


  throat

  region from nasal cavity to top of trachea and oesophagus
• air travels through pharynx before being


  diverted into tranches by epiglottis
• epiglottis


  flap of elastic cartilage
• during inhalation epiglottis covers

  oesophagus, guiding air into trachea
• when swallowing epiglottis covers

  larynx, preventing food from entering
• larynx


  voice box, contains vocal cords

  cartilage and trachea
• vocal cords


  mucous membranes that are able to vibrate as air passes over them
• trachea


  windpipe

  carries air into and out of lungs
• trachea made up of

  C-shaped cartilage rings that hold structure open

  ensures air can pass through it
• at base of trachea

  it splits into two branches, one branch taking air to each lung
• epithelial lining of trachea produces

  mucus, which is able to trap dust and debris, prevents it entering lungs
• cilia that lines trachea are able to move in


  wave like motions to take mucus and debris up to pharynx so that it can be swallowed and digested
• primary bronchi


  end of trachea splits into two primary bronchi
• secondary bronchi


  primary bronchi split further

  takes air into each lobe of lung
• tertiary bronchi


  secondary bronchi dividing
• structure of bronchi has

  C-shaped cartilage rings
• as bronchi gets smaller

  cartridge is more spread out with smooth muscle and elastin forming more of structure
• bronchioles


  tertiary bronchi divide, forming smaller airways (bronchioles) which continue to split until end in millions of terminal bronchioles
• structure of bronchioles do not contain

  cartridge instead made of smooth muscle and elastin
• structure of bronchioles allows to


  control flow of air in lungs, expanding when body needs more oxygen
• two lungs take up


  whole chest cavity except for space between them
• mediastinum


  space between lungs that is occupied by heart and blood vessels
• each lung is divided into

  lobes
• left lung has how many lobes

  two
• right lung has how many lobes

  three
• pleura


  membrane that covers surface of lungs (visceral pleura) and also lines inside of chest (parietal pleura)
• between two layers of pleura is a


  thin layer of pleural fluid

  holds lungs against inside chest wall allows them to slide along wall when breathing
• alveoli


  inside lungs smallest bronchioles open into tiny clusters of tiny air sacs
• each alveolus has wall that is

  only one cell thick, surrounded by network of blood capillaries
• alveolus wall is where


  gases move between blood in capillaries and air in alveoli
• functional units of lungs is

  alveoli
• alveoli make it possible for it to be


  the surface for gases exchange

  allowing net flow of oxygen to pass from airways into blood and carbon dioxide to pass from blood into airways
• ventilation/breathing


  process of which air is moved into and out of lungs
• air flows from places of what pressure to what pressure

  higher pressure to places of lower pressure