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Human Anatomy,                        First Edition
McKinley & O'Loughlin



       Chapter 25 Lecture Outline:
          Respiratory System



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Organization and Functions of
the Respiratory System
    Consists of an upper respiratory tract and a
    lower respiratory tract.
    Conducting portion transports air.
       includes the nose, nasal cavity, pharynx, larynx, trachea,
       and progressively smaller airways, from the primary bronchi
       to the bronchioles
    Respiratory portion carries out gas exchange.
       composed of small airways called respiratory bronchioles
       and alveolar ducts as well as air sacs called alveoli




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Respiratory System Functions
   Breathing (pulmonary ventilation).
      consists of two cyclic phases:
          inhalation, also called inspiration
          exhalation, also called expiration
   Inhalation draws gases into the lungs.
   Exhalation forces gases out of the lungs.
   Gas exchange, gas conditioning, sound
   production, olfaction, and defense.


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Upper Respiratory Tract
   Composed of the nose and nasal cavity,
   paranasal sinuses, pharynx (throat), and
   associated structures.
   All part of the conducting portion of the
   respiratory system.




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Paranasal Sinuses
   Four bones of the skull contain paired air spaces
   called the paranasal sinuses.
      decrease skull bone weight
   Named for the bones in which they are housed.
      frontal
      ethmoidal
      sphenoidal
      maxillary
   Communicate with the nasal cavity by ducts.
   Covered with the same pseudostratified ciliated
   columnar epithelium as the nasal cavity.

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Pharynx
   Common space used by both the respiratory and
   digestive systems.
   Commonly called the throat.
   Funnel-shaped, meaning that it is slightly wider
   superiorly and narrower inferiorly.
   Originates posterior to the nasal and oral cavities and
   extends inferiorly near the level of the bifurcation of
   the larynx and esophagus.
   Common pathway for both air and food.


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Pharynx
   Walls are lined by a mucosa and contain skeletal
   muscles that are primarily used for swallowing.
   Flexible lateral walls are distensible in order to force
   swallowed food into the esophagus.
   Partitioned into three adjoining regions:
       nasopharynx
       oropharynx
       laryngopharynx




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Nasopharynx
   Superiormost region of the pharynx.
   Located directly posterior to the nasal cavity and superior to the
   soft palate, which separates it from the posterior part of the
   oral cavity.
   Normally, only air passes through.
   Material from the oral cavity and oropharynx is typically blocked
   from entering the nasopharynx by the soft palate, which
   elevates when we swallow.
   In the lateral walls of the nasopharynx, paired auditory tubes
   connect the nasopharynx to the middle ear.
   Posterior nasopharynx wall also houses a single pharyngeal
   tonsil (commonly called the adenoids).

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Oropharynx
   The middle pharyngeal region.
   Immediately posterior to the oral cavity.
   Bounded by the edge of the soft palate superiorly and the hyoid
   bone inferiorly.
   Common respiratory and digestive pathway through which both
   air and swallowed food and drink pass.
   2 pairs of muscular arches, the anterior palatoglossal arches
   and the posterior palatopharyngeal arches, form the entrance
   from the oral cavity.
   Lymphatic organs here provide the "first line of defense"
   against ingested or inhaled foreign materials.
   Palatine tonsils are on the lateral wall between the arches, and
   the lingual tonsils are at the base of the tongue.

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Laryngopharynx
   Inferior, narrowed region of the pharynx.
   Extends inferiorly from the hyoid bone and is
   continuous with the larynx and esophagus.
   Terminates at the superior border of the esophagus
   and is equivalent to the inferior border of the cricoid
   cartilage in the larynx.
   The larynx (voice box) forms the anterior wall
   Lined with a nonkeratinized stratified squamous
   epithelium
   Permits passage of both food and air.

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Lower Respiratory Tract
   Conducting airways (larynx, trachea, bronchi,
   bronchioles and their associated structures).
   Respiratory portion of the respiratory system
   (respiratory bronchioles, alveolar ducts, and alveoli).




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