Respiratory System

• Respiratory System


  Function: To ensure that O2 is brought to each cell and CO2 is taken away
• Requirements for respiration


  • High surface area for gas exchange ( alveoli)
  • Moist environment (CO2 and O2 dissolve in water)
• Stages in Respiration


  1. Breathing - Inhalation and exhalation

  2. External Respiration - Exchange of gases between the air and the blood ( LUNGS)

  3. Internal Respiration - Exchange of gases between the blood and body tissues (cells)

  4. Cellular Respiration - Provides energy for the cells
• Mechanics of Breathing


  • The diaphragm and rib muscles work together to produce breathing movements
  • Inhalation - Rib muscles contract, ribs move up and outward, diaphragm contracts and flattens, increasing the volume of the thoracic cavity, decreasing air pressure inside, causing air to be drawn in
  • Exhalation - Rib muscles relax, ribs move downward diaphragm relaxes and becomes dome-shaped, reducing the volume of the thoracic cavity, increasing air pressure, causing air to be pushed out
• Transport of Gases


  • Oxygen - 1% dissolved in plasma, 99% attached to hemoglobin, released to tissues when oxygen levels are low
  • Carbon Dioxide - 7% carried in plasma (as carbonic acid), 23% combined with hemoglobin, 70% as bicarbonate in plasma
• Regulation of Breathing


  1. Receptors in carotid and aortic bodies detect low O2 and high CO2, medulla oblongata (brain) increases breathing rate

  2. Receptors in medulla oblongata detect high CO2, increasing breathing movements
• Structures of the Respiratory System

  • Nostril
  • Nasal Passages
  • Turbinate bones
  • Pharynx
  • Epiglottis
  • Glottis
  • Larynx
  • Trachea
  • Bronchus
  • Lung
  • Bronchiole
  • Alveoli
  • Pleural Membrane
  • Thoracic Cavity
  • Diaphragm
• Nostril


  Passage for oxygen to enter
• Nasal Passages


  • Warm, moist and clean the incoming air
  • Increase surface area
• Pharynx


  Passage for air into respiratory system, and for food and water into digestive system
• Epiglottis


  Flap of cartilage that closes over the opening to the trachea to prevent food and drink from entering
• Glottis


  Large gap between vocal cords when breathing
• Larynx


  Voice box made from cartilage
• Trachea


  Wind pipe, strengthened by rings of cartilage to prevent it from collapsing
• Bronchus


  Creates smaller and finer tubes within the lungs
• Alveoli


  Tiny air sacs in the lungs where gas exchange takes place
• Pleural Membrane


  Outer layer that connects the lungs to the inside of the thoracic cavity
• Thoracic Cavity


  Made up of bone and muscle, protects the lungs
• Diaphragm


  Sits beneath the lungs, involved in breathing
• Inspiratory reserve volume


  Additional volume of air that can be inhaled beyond a normal inhalation
• Expiratory reserve volume


  Additional volume of air that can be exhaled beyond a normal exhalation
• Vital capacity


  Total volume of air that can be moved into or out of the lungs
• Residual volume


  Volume of air that remains in the lungs after a maximal exhalation
• Total lung volume


  Total capacity that can be moved into or out of the lungs
• Tidal volume is the volume of air that is inhaled and exhaled during normal breathing
• Inspiratory capacity is the maximum volume of air that can be inhaled from the end of a normal exhalation
• Functional residual capacity is the volume of air that remains in the lungs at the end of a normal exhalation
• Respiratory system organs


  • Diaphragm
  • Turbinate bones
  • Pharynx
  • Trachea
  • Bronchi
  • Alveoli
  • Ribs
• Tonsillitis is a common inflammation of the tonsils in the pharynx
• Laryngitis is an inflammation of the larynx
• Bronchitis is an inflammation of the bronchi
• Pneumonia is an infection of the lungs
• Pleurisy is a swelling and irritation of the pleura
• Emphysema is a lung disease that causes shortness of breath
• Cystic fibrosis is a genetic disorder that affects the lungs and digestive system
• Asthma is a chronic lung disease that inflames and narrows the airways
• Lung cancer is a type of cancer that begins in the lungs
• Smoking contributes to the development and growth of lung cancer
• Oxygen (O₂)


  Dissolved in plasma
• Oxygen (O₂)


  Attaches to hemoglobin