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Respiratory System Notes

Respiratory System Overview

Functions and Processes

  • Supplies tissues with oxygen (O2) and removes carbon dioxide (CO2).
  • Closely linked to the circulatory system.
  • Respiration: process of gas exchange between atmosphere and tissue cells.
  • Four distinct processes:
    • Pulmonary ventilation: moving air in/out of lungs (breathing).
    • External respiration: gas exchange between lungs and blood.
    • Transport: moving O2 and CO2 from lungs to tissues.
    • Internal respiration: gas exchange between blood and tissues.

Anatomy of the Respiratory System

  • Continuous components:
    • Nose/nasal cavity/paranasal sinuses
    • Pharynx
    • Larynx
    • Trachea
    • Bronchi/Bronchioles
    • Lungs (Alveoli)
  • Associated muscles: diaphragm (major) and intercostals.

Functional Anatomy: Zones

  • Conducting Zone:
    • Rigid conduits (nose to bronchioles) for carrying air.
    • Cleans, warms, and humidifies air.
  • Respiratory Zone:
    • Sites of gas exchange (respiratory bronchioles, alveolar ducts, alveoli).

Nose and Nasal Cavity

  • Functions:
    • Provides airway for respiration.
    • Filters, warms, and humidifies air.
    • Houses olfactory receptors.
  • Nasal Septum: divides nasal cavity into right and left.
  • Vestibule: lined with sebaceous/sweat glands and hair for filtration.
  • Conchae: increases surface area and enhances air turbulence.

Pharynx (Throat)

  • Extends from skull base to the level of the 6th cervical vertebra.
  • Regions:
    • Nasopharynx (air passage only)
    • Oropharynx (food and air passage)
    • Laryngopharynx (divergence for routing air/food).

Larynx (Voice Box)

  • Attached to hyoid bone, connects to trachea.
  • Functions:
    • Maintains airway to trachea.
    • Routes air/food correctly.
    • Voice production via vocal folds (cords).
  • Contains nine cartilages (hyaline and elastic).

Vocal Folds (Cords)

  • Located beneath laryngeal mucosa.
  • Types:
    • Vocal folds (true) for sound production.
    • Vestibular folds (false) protect airway.

Voice Production

  • Occurs during exhalation causing air pressure changes.
  • Factors affecting voice:
    • Pitch: determined by vocal cord length/tension.
    • Loudness: determined by air force across vocal cords.
  • Requires coordination with the pharynx, tongue, and lips.