Histology of respiratory system
Transcript of Histology of respiratory system
Histology of Respiratory system
Chantha JayawardenaDBS
10/11/10
Why should I learn..RS
Objectives
• Components• Functions of each component• Structural features (describe and draw) of
components including structure-function relationship
• Identify (LM)• Physiological aspect• Clinical
Functions
Atmospheric airRTDry
Full of dust
Functions
Atmospheric airRTDry
Full of dust
Functions
Atmospheric airRTDry
Full of dust
Components
Nose
Pharynx
Larynx
Upper respiratory tract
Components
• Divide dichotomously with decreasing diameter
Trachea faculty.ksu.edu.sa
FOD. SL
Components
• Divide dichotomously with decreasing diameter
• Changes takes place gradually
faculty.ksu.edu.sa
FOD. SL
Components
Nasal cavity
Pharynx
Larynx
Trachea
Conducting portion
Respiratory portion
Conditioning air• Adjustment
temperaturehumidity
• Purification /cleaningdust removal
Gas exchange• Between blood and RP
Minimise damage• Against foreign particles
Structure including histology
Variations• Epithelium (thickness, cilia, goblet cells)• Lamina propria (LP)• Submucosa (SM)• Cartilage• Smooth muscles
Nasal cavity
• Cartilages, bones, mucous membrane
• Chonchae (increase surface area and
turbulent airflow – increase contact
between air and MM)
• Hairs (vibrissae) – (trap large particles)
Nasal cavity
Histology of nasal cavity
• Respiratory epithelium (pseudostratified ciliated)
Vein
Vein Vein Vein
Epithelium
Bone
Lamina propria
Veins ; Swell bodies
http://www.lab.anhb.uwa.edu.au
Histology of nasal cavity
• Respiratory epithelium (pseudostratified ciliated)
Mag
Mag
Vein
Vein Vein Vein
Epithelium
Bone
* *
Lamina propria
http://www.lab.anhb.uwa.edu.au
Pharynx and Larynx
• Cartilages and muscles
• Mucous membrane
– Epithelium • (Pseudostratified -
Respiratory side
• (Stratified squamous
Food/ oral side)
Epiglottis - Histology
• Elastic cartilage and mucous membrane
Mag
http://www.lab.anhb.uwa.edu.au
Trachea
• Hyaline cartilage & smooth muscle
• 16-20 “C” shaped rings (support)
• Smooth muscle (trachealis) bridge open ends posteriorly (control DM)
• Between rings- fibroelastic tissue (allow expansion)
www.kgu.de
Trachea - histology
Mag
Lamina propria
Epithelium
Submucosa
Cartilage
http://www.lab.anhb.uwa.edu.au
Trachea - histology
Mag
Lamina propria
Epithelium
Submucosa
Cartilage
http://www.lab.anhb.uwa.edu.au
Trachea - histology
Mag
Lamina propria
Epithelium
Submucosa
Cartilage
http://www.lab.anhb.uwa.edu.au
Trachea
• Draw and label
Principal / primary / main bronchi - histology
• Epithelium similar to trachea (goblet cells )
• Cartilages – interconnected plates
• Smooth muscles beneath the LP
• Submucosa – seromucous glands
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
Segmental / Tertiary bronchi
• Epithelium – less stratified, less goblet cells
• Smooth muscles prominent in the LP
• Less submucosa and seromucous glands
• Few isolated cartilage plates
Segmental / Tertiary bronchi
http://www.lab.anhb.uwa.edu.au
Bronchus
Segmental / Tertiary bronchi
http://www.lab.anhb.uwa.edu.au
Segmental / Tertiary bronchi
• Draw and label
Bronchioles
Bronchioles
http://www.lab.anhb.uwa.edu.au
Bronchioles
• Draw and label
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
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
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
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
http://www.lab.anhb.uwa.edu.au
Alveolar duct and alveoli
• Alveolar macrophages – interalveolar septum, surface of alveoli
http://www.lab.anhb.uwa.edu.au
Alveoli and blood-gas barrier
• Epithelium of alveoli & capillaries become very thin
• Basement membrane of two epithelia fused each other – thin barrier
Blood-gas barrier
• Draw and label
Trachea Bronchus Bronchiole Alveoli
Epithelium
Lamina propria
Submucosa
cartilage
Thickness of epitheliumCiliaGoblet cellsSmooth muscle
Cartilage
Sero-mucous glandsFunction
Trachea Bronchus Bronchiole Alveoli
References
http://www.lab.anhb.uwa.edu.au//