Ch 22 Respiratory System: Part a major function-respiration



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Ch 22 Respiratory System: Part A

  • Major function-respiration

    • Supply body with O2 for cellular respiration; dispose of CO2, a waste product of cellular respiration

  • Also functions in ____________ and ____________________

  • Processes of Respiration

    • Pulmonary ventilation (breathing)-


    • External respiration-

    • Transport-

    • Internal respiration-

  • Respiratory System: Functional Anatomy

  • Major organs

    • Nose, nasal cavity, and paranasal sinuses

    • Pharynx

    • Larynx

    • Trachea

    • Bronchi and their branches

    • Lungs and alveoli

  • Respiratory zone-

  • Conducting zone-

  • The Nose

    • Functions

  • Two regions-external nose and nasal cavity

  • Nasal Cavity

  • Olfactory mucosa contains olfactory epithelium

  • Respiratory mucosa

  • Nasal conchae-superior, middle, and inferior



  • Homeostatic Imbalance

  • Rhinitis



  • Pharynx



  • Three regions

    • Nasopharynx

    • Oropharynx

    • Laryngopharynx

  • Larynx

    • Functions

  • Nine cartilages of larynx

    • All hyaline cartilage except epiglottis

    • Thyroid cartilage with laryngeal prominence (Adam's apple)

    • Epiglottis-elastic cartilage; covers laryngeal inlet during swallowing; covered in taste bud-containing mucosa

  • Vocal ligaments-

  • Vestibular folds

  • Voice Production





  • Vocal folds may act as sphincter to prevent air passage

    • Example-Valsalva's maneuver



  • Trachea

  • Bronchi



  • Conducting Zone Structures

    • Trachea  right and left main (primary) bronchi





  • Branches become smaller and smaller 

    • Bronchioles-less than 1 mm in diameter

    • Terminal bronchioles-smallest-less than
      0.5 mm diameter

  • From bronchi through bronchioles, structural changes occur

  • Respiratory Zone

  • Begins as terminal bronchioles  respiratory bronchiolesalveolar ducts alveolar sacs

    • Alveolar sacs contain clusters of alveoli

      • ~300 million alveoli make up most of lung volume

      • Sites of gas exchange

  • Respiratory Membrane

  • Alveolar walls

    • Single layer of squamous epithelium (type I alveolar cells)

    • Scattered cuboidal type II alveolar cells secrete surfactant and antimicrobial proteins

  • Alveoli

    • Surrounded by fine elastic fibers and pulmonary capillaries

    • Alveolar pores connect adjacent alveoli

    • Alveolar macrophages keep alveolar surfaces sterile

      • 2 million dead macrophages/hour carried by cilia  throat  swallowed

  • Lungs

    • Apex-

    • Base-

    • Hilum-

  • Left lung smaller than right

  • Right lung

  • Bronchopulmonary segments (10 right, 8–10 left) separated by connective tissue septa

    • If diseased can be individually removed

  • Blood Supply

  • Pulmonary circulation (low pressure, high volume)

  • Bronchial arteries provide oxygenated blood to lung tissue



  • Mechanics of Breathing

  • Pulmonary ventilation consists of two phases

    • Inspiration-

    • Expiration-

  • Homeostatic Imbalance

  • Atelectasis (lung collapse) due to

    • Plugged bronchioles  collapse of alveoli

    • Pneumothorax-air in pleural cavity

  • Pulmonary Ventilation

  • Mechanical processes that depend on volume changes in thoracic cavity

    • Volume changes  pressure changes

    • Pressure changes  gases flow to equalize pressure

  • Inspiration

  • Expiration

    • Quiet expiration normally passive process




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