1.2 Energy subsystem phonation

1.2.1 Respiratory system: the lungs, bronchi, and trachea

Illustration 1 Respiratory tract Illustration 2 Trachea and bronchi Illustration 3 Lungs

The lungs have a sponge like and soft texture and are honeycombed with epithelium, having a 50 times larger surface area in total than the outer surface of human skin.

The airways are divided into an upside-down tree like structure with trachea and bronchi, the trachea divides into the two main bronchi that enter the roots of the lungs. The bronchi continue to divide within the lung, and after multiple divisions, give rise to bronchioles.

The trachea has an inner diameter of about 25 millimetres (1.0 in) and a length of about 10 to 16 centimetres (4 to 6 in). There are about fifteen to twenty incomplete C-shaped cartilaginous rings that reinforce the anterior and lateral sides of the trachea to protect and maintain the airway, leaving a membranous wall (pars membranacea) dorsally without cartilage.

Illustration 1. Respiratory apparatus

  1. nasal cavity;
  2. pharynx;
  3. oral cavity;
  4. epiglottis;
  5. fold threshold;
  6. ventricle of the larynx;
  7. vocal fold;
  8. thyroid cartilage;
  9. larynx;
  10. trachea;
  11. bifurcation of the trachea;
  12. the principal right bronchus;
  13. left main bronchus;
  14. upper lobe of the right lung;
  15. upper lobe of the left lung;
  16. middle lobe of the right lung;
  17. middle lobe of the left lung;
  18. the lower lobe of the right lung

Illustration 2. The trachea and bronchi

  1. guttural boss (Adam's apple);
  2. thyroid cartilage;
  3. ligament;
  4. cricothyroid ligament;
  5. arched tracheal cartilage;
  6. circular ligaments of the trachea;
  7. oesophagus;
  8. bifurcation of the trachea;
  9. main right bronchus;
  10. main left bronchus;
  11. aorta.

Illustration 3 Lungs

  1. larynx;
  2. trachea;
  3. apex of the lung;
  4. costal surface;
  5. bifurcation of the trachea;
  6. upper lobe of lung;
  7. horizontal fissure of the right lung;
  8. major fissure;
  9. cardiac notch of the left lung;
  10. middle lobe of lung;
  11. lower lobe of lung;
  12. diaphragmatic surface;
  13. base of the lung.
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