Lab 10: The Respiratory System

Overview

• Focus: Organization, anatomy, and histology of the respiratory system
• Divisions:
  • Tracts:
    • Upper respiratory tract
    • Lower respiratory tract
  • Functional Sections:
    • Conducting Zone
    • Respiratory Zone

Respiratory System Divisions

Upper Respiratory Tract (URT)

• Includes: Nose, nasal cavity, pharynx, and sinuses
• Infections: Sinusitis, rhinitis (nasal infection)

Lower Respiratory Tract (LRT)

• Includes: Larynx, trachea, bronchi, and lungs
• Infections: Laryngitis, bronchitis, pneumonia
• Mnemonic: Lower respiratory tract includes the larynx

Functional Sections

Conducting Zone

• Passage for air into the body
• Includes: Nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles

Respiratory Zone

• Site for gas exchange
• Includes: Respiratory bronchioles, alveolar ducts, alveoli
• Alveoli: Composed of simple squamous epithelium

Major Functions of the Respiratory System

1. Gas Exchange: Inhale oxygen, exhale carbon dioxide
2. Air Processing:
   • Warmed, humidified, and cleansed as it travels
   • Voice production via vocal cords in larynx
   • Olfaction: Detection of smells
   • Mucus production to trap particles

Anatomy of the Respiratory System

Nasal Cavity and Sinuses

• Concha (shelves): Superior, middle, and inferior
• Meatuses (passageways): Where air travels
• Paranasal Sinuses:
  • Frontal sinus
  • Sphenoid sinus
  • Maxillary sinus
  • Ethmoid sinus

Pharynx

• Three Parts: Nasopharynx, oropharynx, laryngopharynx
• Functions as a pathway for both air and food
• Contains: Tonsils and opening of the Eustachian tube

Larynx

• Known as the voice box
• Cartilaginous structure containing vocal cords
• Nine cartilages: Thyroid, Cricoid, Arytenoid, Corniculate, Cuneiform

Trachea

• Known as the windpipe
• Composed of C-shaped cartilages
• Connects larynx to bronchi

Lungs

• Right lung: Three lobes (superior, middle, inferior)
• Left lung: Two lobes (superior, inferior)
• Divided by oblique and horizontal fissures in the right lung and an oblique fissure in the left lung

Bronchial Tree and Respiratory Zone

• Branching network of airways
• Bronchi:
  • Primary bronchi
  • Secondary (lobar) bronchi
  • Tertiary bronchi
• Bronchioles:
  • Smaller airways without cartilage

Alveoli

• Site of gas exchange
• Highly vascularized with capillary networks
• 300-400 million alveoli
• Large surface area equivalent to a tennis court for gas diffusion