S01 Respiratory System

Respiratory System Division

• Labels

URT

Nasal Cavity, Paranasal Sinuses, Nasopharynx, Trachea, Bronchi

Cleans, Warms, Moistens Air

Within Nasal Cavity: Vibrissae(Hairs) Trap Particulates, Rich Capillary Network, Seromucous Gland Water Secretion

• Layers (4)
• Respiratory Epithelium: Ciliated Pseudostratified Columnar
  • Ciliated Columnar; Beat to Waft Mucous Up Airway → Swallowed/Expelled
  • Abundant Goblet Cells; Secrete Mucin, Stain Poorly. Mucous Traps Particulates and Pathogens - Preventing Infection
    • Serous Glands Stain Darkly
  • Basal Cells; Proliferate to Maintain Tissues
  • Small Granule/Kulchitsky: (DNES) - Secrete Substances such as 5-HT
  • Brush Cells: Columnar Chemosensory
  • Image - Epithelium & Apical Surface
  • Image - Nasopharynx Epithelium

LRT

Larynx, Trachea, Bronchi

• Epiglottis: Prevents food entering Trachea

  • Non-Keratinised Stratified Squamous Epithelium

• Vestibule: Respiratory Epithelium

• False Vocal Cords (Vestibular)

  • Ventricle:

• True Vocal Cords: Non-Keratinised Stratified Squamous Epithelium

  Protection from Abrasion, Desiccation of Constant Air Movement

  • Image - Vocal Folds

• Trachea

  • Image - Trachea Cross Section
  • Image - Trachea Layers
  • C-Shaped Hyaline Cartilage Rings
    • Incomplete Posteriorly to allow Bolus Movement down Oesophagus
    • Dense Fibroelastic Tissue between
  • Trachealis Muscle Completes Ring
    • Contracts to Reduce Tracheal Diameter → Increase Intra-thoracic Pressure → Aids Cough
  • Submucosa Binds to Perichondrium of Cartilage Rings
  • Submucosa contains Mixed Sero-mucinous Glands, Decreasing Abundance Distally

• Main Bronchus

  • Begins at Carina - Last Tracheal Cartilage.
    • Lowest Point at which Foreign Objects can Initiate Cough
  • Cartilage: Individual Small Flat Plates
  • Fewer Goblet Cells
  • Smooth Muscle Layer Separates LP//SM
    • Grows Distally
  • LP Higher Elastin Content
  • Submucosa Fewer Sero-mucinous Glands
  • Image - Main Bronchus Layers
  • Image - Bronchus Cross Section

• Segmental Bronchus

  • Pseudostratified Cells Columnar (Less Tall)
  • Smooth Muscle encircles LP
  • Seromucinous Glands Dec. in Mucosa
  • Fewer Cartilage Plates
  • Image - Segmental Bronchus Cross-Section

Bronchioles

• Pseudostratified Columnar ⇒ Simple Cuboidal Epithelium (Terminal Bronchiole)