1. Histology of the Respiratory System

2. The respiratory system consists of 3 principle regions:
conducting portion, consisting of the nasal cavity, nasopharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles.
respiratory portion, consisting of respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli.
structures of ventilating mechanism, which creates pressure differences that move air. It includes the diaphragm, rib cage, intercostal muscles, abdominal muscles and elastic connective tissue in the lungs.

3. Conducting Portion
System of ducts --- conducts air to alveoli in the lungs
Function --- Conditioning of the air --- Warming, moistening and removal of particulate materials

4. Conducting Portion Details of organization:
presence of hyaline cartilage in the larynx, trachea, extrapulmonary and intrapulmonary bronchi.
elasticity of the lungs.
3. Ciliated cells and goblet cells in the epithelium
4. Changes in the epithelium from the nasal cavity to the alveoli of the lungs:
Pseudostratified Columnar => Simple Columnar =>Simple Cuboidal => Simple Squamous.

5. Larynx Mucosa Tube kept open hyaline or elastic (Epiglottis) cartilage
Skeletal muscle surrounds cartilage on outside and present between the cartilage and mucosa
Mucosa
Pseudostratified columnar epithelium containing cilia and goblet cells
Unkeratinized stratified squamous epithelium – only in the epiglottis and the vocal folds

6. Trachea 20 C-shaped hyaline cartilages
Mucosa has pseudostratified columnar epithelium with cilia and goblet cells
Submucosa has mixed glands
20 C-shaped hyaline cartilages

7. Low Magnification of a Cross Section Through the Trachea
1. Lumen
2. Pseudostratified ciliated
columnar epithelium 3. Submucosa 4. Hyalin cartilage 5. Perichondrium 6. Adventitia 7. Mixed glands 8. Secretory duct

8. Epithelium of the Trachea
1. Lumen 2. Cilia 3. Columnar epithelial cells 4. Prominent thick basal membrane 5. Lamina propria 6. Basal cell layer 7. Goblet cell

9. Bronchi anatomy:
Two main extrapulmonary bronchi -- histologically similar to the trachea
Intrapulmonary bronchi
– Primary bronchi - Lobar bronchi
- Secondary bronchi -- Segmental bronchi
- Tertiary bronchi - interlobular bronchi

10. Intrapulmonary Bronchi
Pseudostratified columnar epithelium containing cilia and goblet cells
Smooth muscle - between mucosa and cartilage
Mixed glands lie between muscle layer and cartilagous plates
Cartilage - Irregular shaped cartilaginous plates

11. Three-dimensional Representation of an Intrapulmonary Bronchus
Bronchi
Three-dimensional Representation of an Intrapulmonary Bronchus
cartilage plate
lamina propria
pseudostratified columnar epithelium with cilia
and goblet cells
smooth muscle

12. Bronchioles – smallest branches of bronchi:
Preterminal bronchiole penetrate lobule at its apex and enter inside the lobule, branches into terminal bronchioles

13. Bronchioles: Epithelium
in the larger bronchioles -- Simple columnar, in smaller bronchioles --- tall cuboidal
Goblet cells have disapeared
and cells of Clara (tall, non-ciliated secretory cells, produce surfactant) – apeare

14. Bronchioles
No glands or cartilage are present

15. Representation of the Cells of Clara
Bronchioles
Three-dimensional
Representation of a Preterminal
Bronchiole
Schematic
Representation of the Cells of Clara
mucosa
simple columnar epithelium
lamina propria
cells of Clara
smooth muscle
neuro-epithelial body
cells of Clara

16. Respiratory Portion

17. Respiratory Portion Consists of smaller ducts and sacs
Lie inside lung lobules
Provides exchange of gases

18. Schematic Representation of a Lung Lobule
Lung Lobules
Schematic Representation of a Lung Lobule
bronchiolus
pulmonary artery
lymphatic vessel
pulmonary vein
preterminal bronchiole
respiratory bronchioles
alveoli
visceral layer
parietal layer

19. Respiratory Bronchioles
Branch from terminal bronchioles and have Alveoli - thin bulging sacs - in walls
Gas exchange takes place in alveoli

20. Respiratory Bronchioles
Schematic of the Respiratory Portion of a Lung Lobule
Smooth muscle
respiratory bronchiole
alveolar ducts
alveoli
interalveolar septum
sacculus alveolaris

21. Respiratory Bronchiole
1. High cuboidal epithelium 2. Alveolus
3. Interalveolar septum 4. Lumen

22. Alveolar ducts -- long air passages ,
Alveolar sacs – round air spaces
surrounded by clusters of alveoli
Interalveolar septa – connective tisue - separate neighboring alveoli
Alveolar pores -- direct contact between 2 alveoli

23. The Lung Demonstrating the Basic Structures
1. Alveolar sacs 2. Alveoli 3. Interalveolar septa

24. Epithelium of Alveoli Has two types of cells
Pneumocyte (or alveolocytes) type I (Simple squamous alveolar epithelium)
Pneumocyte type II (Surfactant secreting cells) (NOTE: surfactant decrease surface tension in alveoli preventing their collapsing)
Alveolar macrophages (dust cells) – present in the cavity

25. 1. Carbon particles 2. Pneumocyte type II (Surfactant secreting cells) 3. Pneumocyte type I

26. Barrier between Air and Blood
Cytoplasm of epithelium lining the alveoli
Basal lamina of the epithelium
Basal lamina of the capillary endothelium
Cytoplasm of capillary endothelium

27. Structure of the Interalveolar Septa
secretory cell
basal lamina of endothelium
basale lamina of epithelium
endothelium
aveolar
macrophage
epithelium
capillary
endothelium
alveolus
surfactant
diffusie van CO2
endothelial cell
diffusie van CO2
simple squamous
alveolar epithelial cell
red blood cell
Connective tissue cell
alveolus

29. Blood Vessels
Branches of pulmonary artery form capillaries in interalveolar septa (carry deoxygenated blood)
Bronchial arteries supply walls of bronchi and connective tissue

30. Terminal Part of the Lungs

31. Lymphatic Drainage Run in connective tissue of the lungs (
Visceral pleura, interlobular septa and dense connective tissue surrounding the bronchi and bronchioles, arteries and veins
Vessels not present in the interalveolar septa

32. Acinus is Structural and Functional Unit of the Lung

35. Lymphatic Drainage
Epithelium
Lamina propria
Smooth muscle
Cartilage
Glands
Lymphatic and blood vessels

36. Control questions Name, group Topic of the lecture
Air-conducting structures – general plane of organization:
-- epithelium – cells?
----another layers ?