Respiratory system

• Respiration


  Exchange of O2/CO2 between atmosphere, blood, and cells
• Organs of the respiratory system

  • Nose, pharynx, larynx, trachea, bronchi, lungs

  
• Cardiovascular and respiratory systems


  Work together to supply O2 to and remove CO2 from cells
• External nares


  Openings into the nose
• Internal nares


  Connect nose and pharynx
• Nose


  • Coarse hairs line the vestibules to filter large dust particles
  • Three shelves formed by turbinate bones: superior, middle, and inferior meatus
  • Olfactory receptors located in the superior meatus
  • Functions: warm and moisturize air, smell, speech tone
• Pharynx


  Passageway for food and air, resonating chamber for speech
• Divisions of the pharynx

  • Nasopharynx: internal nares and eustachian tubes
  • Oropharynx: connection to mouth (fauces)
  • Laryngopharynx: connects with esophagus and larynx

  
• Larynx


  • Supporting cartilage: thyroid, epiglottis, cricoid, arytenoid, corniculate and cuneiform
  • Mucous membrane with false and true vocal cords
  • Glottis: opening over true vocal cords
  • Sound produced by air vibrating vocal cords

  
• Trachea


  • Pseudostratified epithelium with cilia and goblet cells
  • Smooth muscle and connective tissue
  • Supporting cartilage: stack of Cs
  • Cough reflex stimulated by foreign object
  • Tracheostomy done if object cannot be expelled
• Bronchial tree


  1. Trachea branches into left and right primary bronchi

  2. Primary bronchi branch into secondary bronchi

  3. Secondary bronchi branch into tertiary bronchi

  4. Tertiary bronchi branch into bronchioles

  5. Bronchioles branch into terminal bronchioles
• Lungs

  • Pleural membrane: parietal and visceral pleura, pleural cavity
  • Segments supplied by each tertiary bronchi
  • Lobules wrapped in elastic connective tissue, each with lymphatic, arteriole, venule, bronchioles
  • Terminal bronchioles subdivide into respiratory bronchioles
  • Respiratory bronchioles divide into alveolar ducts
  • Alveoli surround the alveolar ducts, surrounded by capillary network
  • Respiratory gases pass through alveolar-capillary membrane
  • Coated with surfactant to reduce surface tension

  
• Respiration process


  1. Ventilation or breathing: inhalation - diaphragm and intercostal muscles contract, pressure decreases in lungs, air rushes in; exhalation - diaphragm and intercostal muscles relax, pressure increases in lungs, air rushes out

  2. External respiration: exchange of gases between lungs and blood

  3. Internal respiration: exchange of gases between blood and body cells
• bronchial tree refers to all branches of the airways within the lung
• the trachea is also known as the windpipe
• the bronchi are tubes that branch off from the trachea into the lungs
• Tunics (from the inside out)


  • Mucosa: mucous membrane attached to thin layer of visceral muscle
  • Submucosa: loose connective tissue
  • Muscularis: skeletal or smooth muscle
  • Adventitia: serous membrane made of connective and epithelial tissue
• Adventitia


  Also called visceral peritoneum
• The Mouth or Oral Cavity


  • Lips and cheeks move the food mixed with saliva to begin mechanical digestion
  • Mastication is the process of chewing and mixing food with saliva
• Structure of the Mouth or Oral Cavity

  • Cavity lined with mucous membrane
  • Cavity floor formed by tongue
  • Cavity roof formed by hard and soft palate
  • Cavity sides formed by cheeks
  • Cavity opening guarded by lips
• External nares


  Openings into the nose
• Internal nares


  Connect nose and pharynx
• Vestibules


  • Coarse hairs line them
  • Filter large dust particles
• Turbinate bones


  • Form three shelves: superior, middle, and inferior meatus
• Olfactory receptors


  Located in the superior meatus
• Functions of internal nose

  • Warm and moisturize air
  • Smell
  • Speech tone
• Nasopharynx


  Contains internal nares and eustachian tubes
• Oropharynx


  Connection to mouth (fauces)
• Laryngopharynx


  Connects with esophagus and larynx
• supporting cartilage, larynx, or voice box


  • Thyroid: largest, Adam's apple
  • Epiglottis: prevents food and liquids from entering trachea
  • Cricoid: connects with first tracheal ring
  • Arytenoid: attach to vocal cords and laryngeal muscles
  • Corniculate and cuneiform: connect epiglottis to arytenoid cartilage
• Larynx form and function

  • Mucous membrane: two pairs of folds (false vocal cords, true vocal cords)
  • Glottis: opening over true vocal cords
  • Sound produced by air vibrating vocal cords
• Trachea


  • Tubular passageway for air
  • Anterior to esophagus
  • Extends from cricoid cartilage to fifth thoracic vertebra
• Trachea structure


  • Pseudostratified epithelium with cilia and goblet cells
  • Smooth muscle and connective tissue
  • Supporting cartilage: stack of Cs
• Cough reflex


  Stimulated by foreign object
• Tracheostomy


  • Done if object cannot be expelled
  • Usually between second and third tracheal cartilages
  • Can be closed when object removed
• Primary bronchi


  Trachea branches into left and right
• Bronchial tree


  1. Primary bronchi branch into secondary bronchi

  2. Secondary bronchi branch into tertiary bronchi

  3. Tertiary bronchi branch into bronchioles

  4. Bronchioles branch into terminal bronchioles
• Pleural membrane


  • Encloses and protects lungs
  • Parietal pleura outer
  • Visceral pleura inner
  • Pleural cavity between pleura, prevents friction
• Pleurisy


  Inflammation of parietal pleura
• Lung segments


  • Supplied by each tertiary bronchi
  • Lobules wrapped in elastic connective tissue
  • Each has lymphatic, arteriole, venula, bronchioles