3. Objectives
• Components
• Functions of each component
• Structural features (describe and draw) of
components including structure-function
relationship
• Identify (LM)
• Physiological aspect
• Clinical
12. Nasal cavity
• Cartilages, bones, mucous membrane
• Chonchae (increase surface area and
turbulent airflow – increase contact
between air and MM)
• Hairs (vibrissae) – (trap large particles)
23. Principal / primary / main bronchi -
histology
• Epithelium similar to trachea (goblet cells )
• Cartilages – interconnected plates
• Smooth muscles beneath the LP
• Submucosa – seromucous glands
24. Bronchi - histology
• Diameter decreases
• Epithelium similar to trachea
• Shape and arrangement of the cartilage and
smooth muscle are different
• With decrease of DM – Cartilage ring become
irregular isolated plates
• Smooth muscles in the LP are spirally arranged
• Lymphocytes & lymphoid aggregations in the LP
25. Segmental / Tertiary bronchi
• Epithelium – less stratified, less goblet
cells
• Smooth muscles prominent in the LP
• Less submucosa and seromucous
glands
• Few isolated cartilage plates
32. Respiratory bronchiloes
• Sac like alveoli along the wall
• Epithelium – ciliated cuboidal
• No goblet cells, Clara cells present
• No cartilage
• Little smooth muscle in the LP
• No submucosa
33. Alveolar duct and alveoli
• Exchange of gas
• Epithelium simple squamous
• Elastic and reticulin fibers – elastic recoil & prevent
over expansion
• Smooth muscles only at the openings of alveloar
ducts
• Cigarette smoking – break down alveolar tissue and
impair repair of tissue - emphysema
34. Alveolar duct and alveoli
• Cells become very thin for gas
exchange
• Several cell types
• Squamous alveolar cells (Type I) – 97 %
– Desmosomes & tight junctions present -
prevent leakage of tissue fluid
35. Alveolar duct and alveoli
• Surfactant secreting cells (Type II)– 3 % -
reduce surface tension
– Round cells
– Can proliferate & produce new type I & II cells
– Respiratory distress syndrome – Immature baby
37. Alveolar duct and alveoli
• Alveolar macrophages – interalveolar septum,
surface of alveoli
http://www.lab.anhb.uwa.edu.au
38. Alveoli and blood-gas barrier
• Epithelium of alveoli & capillaries become
very thin
• Basement membrane of two epithelia fused each
other – thin barrier
