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.