respiratory

• Respiratory system

  Structures used to acquire O2 and remove CO2 from the blood
• All cells in the body require O2 to synthesize the chemical energy molecule, ATP
• CO2 is a by-product of ATP production and must be removed from the blood
• Increased levels of CO2 will lower the pH of the blood
• Structures of the respiratory system

  • External nose
  • Nasal cavity
  • Pharynx
  • Larynx
  • Trachea
  • Bronchi
  • Lungs

  
• Upper respiratory tract


  • Structures from the nose to the larynx

  
• Lower respiratory tract


  • Structures from the trachea through the alveoli in the lungs

  
• Conducting zone


  • Structures from the nose to the air tubes within the lungs used strictly for ventilation
• Respiratory zone


  • Small air tubes in the lungs and the alveoli where gas exchange occurs

  
• Functions of the respiratory system

  • Ventilation
  • External respiration
  • Gas transport
  • Internal respiration

  
• Ventilation

  Breathing, the movement of air into and out of the lungs
• External respiration

  The exchange of O2 and CO2 between the air in the lungs and the blood

  
• Gas transport

  O2 and CO2 travel in the blood to and from cells
• Internal respiration

  The exchange of O2 and CO2 between the blood and the tissues
• Additional functions of the respiratory system

  • Regulation of blood pH
  • Production of chemical mediators
  • Voice production

  
• Olfaction


  The sensation of smell occurs when airborne molecules are drawn into the nasal cavity
• Protection


  The respiratory system provides protection against some microorganisms by preventing them from entering the body and removing them from respiratory surfaces
• Structures of the upper respiratory tract

  • External nose
  • Nasal cavity
  • Pharynx
  • Larynx

  
• Structures of the lower respiratory tract

  • Trachea
  • Bronchi
  • Tracheobronchial tree in lungs
  • Alveoli

  
• Trachea


  Windpipe, consists of 16 to 20 C-shaped pieces of cartilage called tracheal rings, lined with ciliated pseudostratified columnar epithelium
• Smoking kills cilia
• Coughing dislodges materials from trachea
• Bronchi


  Divide into right and left main (primary) bronchi in the lungs at the carina, lined with cilia, contain C-shaped pieces of cartilage

  
• Structures of the tracheobronchial tree

  • Primary bronchi
  • Lobar (secondary) bronchi
  • Segmental (tertiary) bronchi
  • Bronchioles
  • Terminal bronchioles
  • Respiratory bronchioles
  • Alveolar ducts
  • Alveoli

  
• Bronchodilation


  The smooth muscle relaxes, making the bronchiole diameter larger
• Bronchoconstriction


  The smooth muscle contracts, making the bronchiole diameter smaller
• Asthma attack


  Contraction of terminal bronchioles leads to reduced air flow
• Alveoli


  Small air-filled sacs where air and blood come into close contact and gas exchange occurs, surrounded by capillaries, 300 million in lungs

  
• From the terminal bronchioles to the alveoli, there are multiple levels of branching
• Respiratory bronchioles


  Have a few attached alveoli

  
• Alveolar ducts


  Arise from the respiratory bronchioles and open into alveoli

  
• Alveolar sacs


  Chambers connected to two or more alveoli at the end
• Respiratory membrane


  In lungs where gas exchange between air and blood occurs, formed by walls of alveoli and capillaries, alveolar ducts and respiratory bronchioles also contribute, very thin for diffusion of gases

  
• Layers of respiratory membrane

  • Thin layer of fluid from alveolus
  • Alveolar epithelium (simple squamous)
  • Basement membrane of alveolar epithelium
  • Thin interstitial space
  • Basement membrane of capillary endothelium
  • Capillary endothelium (simple squamous)

  
• Components of the thoracic wall

  • Thoracic vertebrae
  • Ribs
  • Costal cartilages
  • Sternum
  • Associated muscles
• Thoracic cavity


  The space enclosed by the thoracic wall and the diaphragm

  
• Diaphragm


  A sheet of skeletal muscle separating the thoracic cavity from the abdominal cavity
• The diaphragm and skeletal muscles of the thoracic wall change thoracic volume during ventilation
• Lungs


  Primary organ of respiration, cone shaped, the base rests on the diaphragm, the apex extends above the clavicle, right lung has 3 lobes, left lung has 2 lobes, contains many air passageways (divisions)

  
• Oxygenated blood has passed through the lungs and picked up O2