respiratory

• The respiratory system oversees gas exchanges between the blood and external environment
• Exchange of gasses takes place within the lungs in the alveoli
• The respiratory system can purify, warm, and humidify the incoming air
• Other Functions of the Respiratory System

  • Regulation of blood pH
  • Voice Production
  • Olfaction
  • Innate Immunity
• Organs of the Respiratory system

  • Nose
  • Pharynx
  • Larynx
  • Trachea
  • Bronchi
  • Lungs - alveoli
• Nose


  The only externally visible part of the respiratory system
• Nasal cavity


  Divided by a nasal septum, lined with respiratory mucosa that moistens air and traps foreign particles
• Nasal cavity


  • Lateral walls have projections called conchae that increase surface area and air turbulence
  • Separated from oral cavity by the palate
• Paranasal sinuses


  Cavities within bones surrounding the nasal cavity that lighten the skull, act as resonance chambers for speech, and produce mucus
• Pharynx


  Muscular passage from nasal cavity to larynx, with three regions: nasopharynx, oropharynx, and laryngopharynx
• Structures of the Pharynx

  • Auditory tubes
  • Pharyngeal tonsil (adenoids)
  • Palatine tonsils
  • Lingual tonsils
• Larynx


  Routes air and food into proper channels, plays a role in speech, made of rigid cartilages and a spoon-shaped epiglottis
• Structures of the Larynx

  • Thyroid cartilage
  • Epiglottis
  • Vocal cords (vocal folds)
  • Glottis
• Trachea


  Connects larynx with bronchi, lined with ciliated mucosa that expels debris away from lungs, walls reinforced with C-shaped cartilage
• Primary Bronchi


  Formed by division of the trachea, enter the lungs at the hilus
• Lungs


  Principal organs of respiration, occupy most of the thoracic cavity, divided into lobes
• Pulmonary (visceral) pleura


  Covers the lung surface
• Parietal pleura


  Lines the walls of the thoracic cavity
• Bronchioles


  Smallest branches of the bronchi, terminal bronchioles end in alveoli
• Respiratory Zone


  Structures involved in gas exchange: respiratory bronchioles, alveolar ducts, alveoli
• Alveoli


  Site of gas exchange, structure includes alveolar ducts, alveolar sacs, and individual alveoli
• Respiratory Membrane (Air-Blood Barrier)


  Thin squamous epithelial layer lining alveolar walls, with pulmonary capillaries covering external surfaces
• Gas Exchange


  Gas crosses the respiratory membrane by diffusion, oxygen enters the blood and carbon dioxide enters the alveoli, macrophages and surfactant provide protection
• Events of Respiration


  • Pulmonary ventilation - moving air in and out of lungs
  • External respiration - gas exchange between pulmonary blood and alveoli
  • Respiratory gas transport - transport of oxygen and carbon dioxide via bloodstream
  • Internal respiration - gas exchange between blood and tissue cells in systemic capillaries
• Mechanics of Breathing (Pulmonary Ventilation)

  1. Inspiration - diaphragm and intercostal muscles contract, thoracic cavity increases, external air pulled into lungs

  2. Expiration - largely passive, as muscles relax air is pushed out of lungs
• Nonrespiratory air movements can be caused by reflexes or voluntary actions, such as cough, sneeze, laughing, crying, yawning, hiccup
• Respiratory Volumes and Capacities

  • Tidal volume (TV)
  • Inspiratory reserve volume (IRV)
  • Expiratory reserve volume (ERV)
  • Residual volume (RV)
  • Vital capacity
  • Dead space volume
  • Functional volume
• Respiratory capacities are measured with a spirometer
• Clinical Impacts


  • Heimlich Maneuver
  • Intubation
  • Mechanical ventilator
  • Cricothyrotomy
  • Tracheostomy
• The respiratory system oversees gas exchanges between the blood and external environment
• Exchange of gasses takes place within the lungs in the alveoli
• The respiratory system can purify, warm, and humidify the incoming air
• Other functions of the respiratory system

  • Regulation of blood pH
  • Voice production
  • Olfaction
  • Innate immunity
• Organs of the respiratory system

  • Nose
  • Pharynx
  • Larynx
  • Trachea
  • Bronchi
  • Lungs - alveoli
• Nose


  The only externally visible part of the respiratory system
• Nasal cavity

  • Air enters through the external nares (nostrils)
  • Divided by a nasal septum
• Olfactory receptors


  • Located in the mucosa on the superior surface of the nasal cavity
• Respiratory mucosa

  • Lines the rest of the nasal cavity
  • Moistens air
  • Traps incoming foreign particles
• Conchae


  • Projections on the lateral walls of the nasal cavity
  • Increase surface area
  • Increase air turbulence
• Palate


  • Separates the nasal cavity from the oral cavity
  • Anterior hard palate (bone)
  • Posterior soft palate (muscle)