Respiratory System Part 1

Overview

• Focus on the major processes of the respiratory system.
• Introduction to the trace of the respiratory tract.

Major Processes of Respiration

1. Pulmonary Ventilation

   • Movement of air into and out of the lungs.
   • Analogous to a well-ventilated room.
   • Involves physics and muscles.

2. External Respiration (Alveolar Gas Exchange)

   • Gas exchange within lung tissue.
   • Oxygen loaded into bloodstream; CO2 expelled.

3. Respiratory Gas Transport

   • Characteristics of blood for gas transport.
   • Involves hemoglobin and plasma.

4. Internal Respiration (Systemic Gas Exchange)

   • Gas exchange at body's tissues.
   • Oxygen provided to tissues; CO2 waste removed.

Anatomy of the Respiratory System

• Upper Respiratory Tract: Nose to larynx.
• Lower Respiratory Tract: Trachea to alveoli.

Structural Organization

• Conducting Zone: Air passageways (nasal cavity to bronchioles).
• Respiratory Zone: Sites of gas exchange (alveoli and respiratory bronchioles).

Trace through the Respiratory Tract

Nasal Cavity

• Functions: Warms, moistens, and filters air.
• Contains olfactory receptors for smell.
• Nasal septum divides cavity into halves.
• External nares (nostrils) vs. internal nares (choana).
• Turbulence created by nasal conchae.

Pharynx (Throat)

• Common passageway for air, food, and liquids.
• Divided into:
  • Nasopharynx: Posterior to nasal cavity.
  • Oropharynx: Posterior to oral cavity.
  • Laryngopharynx: Posterior to larynx.
• Lined with stratified squamous epithelium for protection.

Larynx (Voice Box)

• Connects pharynx to trachea.
• Composed mostly of hyaline cartilage; epiglottis is elastic.
• Houses vocal cords (voice production).
• Epiglottis: Prevents food/liquid entry into respiratory tract.

Trachea (Windpipe)

• Connects larynx to bronchi.
• Lined with pseudostratified ciliated columnar epithelium.
• Contains incomplete rings of hyaline cartilage with trachealis muscle.

Important Concepts

• Respiratory Mucosa: Lines upper tract with pseudostratified epithelium.
• Mucus Production: From mucosa and paranasal sinuses.
• Inflammation: Rhinitis (nasal) vs. sinusitis (sinuses).
• Vocal Cord Function: True vocal cords produce sound; false cords (vestibular folds) protect during swallowing.

Next Steps

• Examine bronchial tree and alveoli in Part 2.