Exam Notes on Pharynx and Larynx

Pharynx

  • The pharynx is used by both the digestive and respiratory systems.
  • It has three parts, from superior to inferior:

Nasopharynx

  • Located posterior to the nasal cavity.
  • Lined with pseudostratified columnar epithelium.
  • Contains lymphatic tissue nodules (including the pharyngeal tonsil, also known as adenoids) for immune surveillance of saliva and pathogen removal.
  • Contains the opening of the auditory (Eustachian) tube to the middle ear. This opening is normally collapsed and covered by a tissue fold.

Oropharynx

  • Located posterior to the oral cavity.
  • Lined with non-keratinized stratified squamous epithelium for protection during swallowing of rough materials.
  • Contains the lingual tonsil (posterior one-third of the tongue) and two palatine tonsils (one on each lateral side of the oropharynx).
  • The palatine tonsils are the ones most commonly removed in tonsillectomies.

Laryngopharynx

  • Located posterior to the larynx.
  • Lined with non-keratinized stratified squamous epithelium.

Larynx

  • The larynx, also known as the voice box, directs food to the esophagus.
  • Its mucosa contains both stratified squamous and pseudostratified columnar epithelium.
  • The larynx is constructed as a box of nine cartilages with several ligaments, some of which form the vocal folds (vocal cords).
  • It also includes the hyoid bone, which uniquely does not articulate with any other bones.

Cartilages of the Larynx

  • Thyroid cartilage:
    • A single, large fused plate of hyaline cartilage.
    • Forms the anterior wall of the larynx.
    • Connected to the hyoid bone by ligaments.
    • Serves as the anterior anchor for the vocal folds and the epiglottis.
    • The anterior part is called the laryngeal prominence, also known as the Adam's apple.
    • The Adam's apple is generally larger in males, resulting in longer vocal folds and a lower-pitched voice.
    • The thyroid gland is located just inferior to the Adam's apple, wrapping around the anterior surface of the cartilage.
  • Cricoid cartilage:
    • A single, ring-shaped cartilage.
    • Located just above the trachea.
  • Epiglottis:
    • A single, leaf-shaped elastic cartilage.
    • Anchored to the thyroid cartilage.
    • During swallowing, the larynx rises and the epiglottis tips inferiorly to cover the glottis.
  • Other cartilages (arranged in three pairs):
    • Arytenoid cartilages
    • Corniculate cartilages
    • Cuneiform cartilages

Vocal Folds

  • True vocal folds (vocal cords):
    • Two ligaments covered with mucosa.
    • Anchored between the arytenoid and thyroid cartilages.
    • The opening between them is called the rima glottidis.
    • Air passing through the rima glottidis causes the vocal folds to vibrate, producing sound.
    • The vocal folds and the rima glottidis together are called the glottis.
  • Vestibular folds (false vocal cords, ventricular folds):
    • Another pair of ligaments with mucosa, located superior to the true vocal cords.
    • Do not produce sound but enhance high-frequency sounds.