Respiratory Anatomy

Respiratory Anatomy

1. The Nose

   • Lateral and Alar Cartilages: inferior half of nose
     • Ala Nasi: flared part at the inferior end of nose
       • Nostrils: anterior openings of nose
         • Guard Hairs: (vibrissae) : located just inside the nostril
           • Nasal Cavity: internal chamber of the nose
             • Nasal Fossae: the left and right halves of the nasal cavity
               • Nasal Septum: dividing wall of nasal cavity
           • Vestibule: small chamber inside of the nostril
             • Superior/Middle/Inferior Nasal Conchae: (turbinates) : folds of tissue, from lateral wall towards the septum
               • Superior/Middle/Inferior Meatuses: narrow air passage located beneath respective concha
                 • Posterior Nasal Aperture: in the posterior of the nasal cavity

2. The Pharynx

   • Pharynx: muscular funnel about 13 cm, from posterior nasal apertures to larynx
     • Nasopharynx: distal to posterior nasal apertures, superior to soft palate
       • Oropharynx: space located between posterior part of soft palate and epiglottis
         • Laryngopharynx: posterior to larynx, from superior part of epiglottis to the beginning of esophagus

3. The Larynx

   • Larynx: (voice box) : cartilaginous chamber about 4 cm long
     • Epiglottis: located at the superior opening of the larynx
       • Glottis: a collective term for the vocal chords and the space between them
     • Framework of larynx composed of 9 cartilages
       • 1. Epiglottic Cartilage: spoon shaped
       • 2. Thyroid Cartilage: shieldlike shape
       • 3. Cricoid Cartilage: ring-like, inferior to thyroid cartilage
       • 4. + 5. Arytenoid Cartilages: are a pair and posterior to thyroid cartilage
       • 6. + 7. Corniculate Cartilages: are a pair and attached to the upper ends of the arytenoid cartilages
       • 8. + 9. Cuniform Cartilages: are a pair and
       • Intrinsic Ligaments: Vocal Ligaments and Vestibular Ligaments Vocal Ligaments: located inside the vocal chords Vestibular Ligaments: support the vestibular folds
     • Extrinsic Ligaments: Thyrohyoid Ligament and Cricotracheal Ligament Thyrohyoid Ligament: suspends the larynx from the hyoid bone Cricotracheal Ligament: suspends the trachea from the cricoid cartilage

4. The Trachea

   • Trachea: (windpipe) : a rigid tube about 12cm long and 2.5 cm in diameter and located anterior to the esophagus
     • C-shaped Hyaline cartilage Rings: about 16-20 support the trachea
       • Trachealis: spans the open part of the C-shaped rings
         • Adventitia: fibrous connective tissue which is the outermost layer of the trachea
           • Carina: internal median ridge at the most inferior trahceal cartilage

5. The Lungs

   • Lungs: conical organ
     • Concave Base
     • Apex: blunt peak, projects slightly above the clavicle
     • Costal Surface: broad surface facing the rib cage
       • Mediastinal Surface: smaller and concave, faces medially
         • Hilum: a slit on the mediastinal surface through which the main bronchus, blood vessels, lymphatics, and nerves connect to the lung
           • Root of the Lung: made up of the main bronchus, blood vessels, lymphatics, and nerves
             • Left Lung: taller and more narrow than the right
               • Cardiac Impression: indentation in the left lung where the heart presses against
               • Cardiac Notch: part of the cardiac impression, which is visible anteriorly as a cresent shape
               • Superior Lobe
               • Inferior Lobe
               • Oblique Fissure: separates the superior and inferior lobes
             • Right Lung: shorter than the left
               • Superior Lobe
               • Middle Lobe
               • Inferior Lobe
               • Horizontal Fissure: separates the superior and middle lobes
               • Oblique Fissure: separates the middle and inferior lobes

6. Overview

   • Nostrils
     • Nasal Cavity
       • Hard Palate
         • Soft Palate
           • Posterior Nasal Aperture
             • Pharynx
               • Epiglottis
                 • Esophagus
                 • Larynx
                   • Trachea
                     • Main Bronchus
                       • Lobar Bronchus
                         • Segmental Bronchus
                           • Left and Right Lungs
                             • Pleural Cavity
                               • Pleura
                                 • Diaphragm

7. The Bronchial Tree

   • Bronchial Tree: branching system of air tubes, extends from the main bronchus to around 65,000 terminal bronchioles
     • Right Main Bronchus: about 2-3 cm long, wider and more vertical than the left
       • Superior/Middle/Inferior Lobar Bronchi: branch to respective lobe of the lung
         • Segmental Bronchi: the lobar bronchi branch off to these, there are 10 in the right and 8 in the left
           • Bronchioles: 1 mm or less in diameter and are continuations of the airway that lacks supportive cartilage
             • Pulmonary Lobule: part of lung ventilated by one bronchiole
             • Terminal Bronchioles: final branches of conducting division, 0.5 mm or less in diameter, each bronchiole divides to about 50-80 terminal bronchioles
               • Respiratory Bronchioles: two or more branch from each terminal bronchiole, beginning of respiratory division
                 • Alveolar Ducts: thin-walled passages, lined with alveoli, 2-10 ducts emerge from each respiratory bronchiole
                   • Alveolar Sacs: clusters of alveoli arrayed around an atrium
                     • Atrium: a central space, closely equal in length and width
     • Left Main Bronchus: about 5 cm long, narrower and more horizontal than the right
       • Superior/Inferior Lobar Bronchi: branch to respective lobe of the lung

8. The Alveoli

   • Alveolus: pouch about 0.2-0.5 mm thick
     • Squamous Alveolar Cells: thin, broad cells that cover about 95% of alveolar surface area
     • Great Alveolar Cells: round/cubodial cells that cover the other 5% of the surface area
     • Alveolar Macrophages: located in the lumen of the alveoli and its connective tissue
     • Web of Blood Capillaries: surrounding each alveolus
       • Respiratory Membrane: barrier between the alveolar air and blood

9. The Pleurae

   • Visceral Pleura: serous membrane that extends into the fissures
     • Parietal Pleura: when the visceral pleura reaches the hilum, it folds in on itself and forms the parietal pleura
       • Pulmonary Ligament: extension of the parietal pleura, connects it to the diaphragm
       • Pleural Cavity: space between parietal and visceral pleurae, wraps around the lung, potential space
         • Pleural Fluid: slippery film

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