Anatomy of the Respiratory System: Larynx

Overview

• The respiratory system consists of organs involved in breathing: Nose, Pharynx, Larynx, Trachea, Bronchi, and Lungs.
• Focus: Anatomy of the Larynx, its structure, and functions.

Orientation of the Larynx

• Location: Between Hyoid Bone and Trachea, in front of the Esophagus.
• Cervical Vertebrae: Situated from the 4th-5th to 6th-7th cervical vertebrae.
• Functions:
  • Air passage to lungs.
  • Voice production (Phonation).
  • Vocal cords produce sound by rubbing together.

Structural View

• Anterior View:
  • Hyoid bone above, trachea below.
• Posterior View:
  • Larynx structure details.

Larynx Composition

• Cartilages: Total of 6 types (3 paired, 3 unpaired).
  • Unpaired Cartilages:
    • Epiglottis (Purple)
    • Thyroid Cartilage (Blue)
    • Cricoid Cartilage (Light Green)
  • Paired Cartilages:
    • Arytenoid Cartilage (Yellow)
    • Corniculate Cartilage (Red)
    • Cuneiform Cartilage (Green)

Detailed Cartilage Overview

• Thyroid Cartilage:
  • Composed of two laminas forming Adam’s apple.
  • Processes: Superior horn (upward), Inferior horn (downward).
• Cricoid Cartilage:
  • Anterior arch and posterior plate.
  • Articular surfaces: Arytenoid and Thyroid.
• Epiglottis:
  • Behind thyroid cartilage and hyoid bone.
  • Function: Closes respiratory system when swallowing.
• Arytenoid Cartilages:
  • Triangular shape with apex and base.
  • Processes: Vocal (anterior), Muscular (posterior).
• Corniculate Cartilage:
  • Sits on Arytenoid, muscle attachment.
• Cuneiform Cartilage:
  • Located in aryepiglottic fold, forms Cuneiform tubercle.

Larynx Connections (Juncturae Laryngis)

• Articular System:
  • Continuous articulation: uninterrupted.
  • Discontinuous articulation: contains joint cavities.
• Continuous Connections:
  • Cartilaginous connection: Between Corniculate and Arytenoid cartilage.
  • Fibrous connections: Thyrohyoid and Cricothyroid membranes, Cricotracheal ligament, Thyroepiglottic and Hyoepiglottic ligaments.
• Discontinuous Connections:
  • Synovial Joints: Cricothyroid and Cricoarytenoid articulations.

Laryngeal Wall Layers

• Tunica Mucosa:
  • Innermost lining with respiratory and stratified squamous epithelium.
  • Contains glands and lymph nodules.
• Tela Submucosa:
  • Forms fibroelastic membranes: Quadrangular and Conus Elasticus.
• Cartilage and Muscle Layer:
  • Muscles: Open/narrow laryngeal inlet and Rima Glottidis.
• Tunica Adventitia:
  • Outer connective tissue layer.

Laryngeal Cavity

• Division:
  • Laryngeal Vestibule: Entrance to vestibular folds.
  • Glottis: Between vestibular and vocal cords.
  • Infraglottic cavity: From vocal cords to cricoid cartilage.
• Mechanism:
  • Phonation: Vocal cords vibrate for sound production.
  • Breathing: Cords open for air passage.
  • Laryngeal ventricles: Act as resonators for sound.

Conclusion

• Review of the larynx's anatomy and function in respiration and phonation.
• Next topic: Anatomy of the Trachea.