RESPIRATORY SYSTEM
Respiratory system
conducting
system
respiratory
zone
2
Conducting system
• Upper
• Lower
– extrapulmonary:
• trachea
• main bronchi
– intrapulmonary:
• main bronchi
• lobar and segmental bronchi
• terminal bronchioles
3
Extrapulmonary airways
• Tunica mucosa
• Tunica fibro-musculocartilaginea
lumen
• External tunic tracheal epithelium
adventitia
glands
muscular
fibers
4
Hyaline cartilage
Trachea
Tunica mucosa
•
Respiratory epithelium
• Pseudostratified ciliated epithelium
•
Lamina propria:
-
Loose connective tissue
-
Sero-mucous glands
-
Deep portion (tela submucosa):
-
Loose connective tissue
-
Mucous and sero-mucous glands
5
Trachea
Tunica mucosa
Respiratory epithelium
Seromucous gland
Hyaline Cartilage
H.E. 10X
6
RESPIRATORY EPITHELIUM
H.E. 20X
RESPIRATORY EPITHELIUM
Goblet cell
cilia
Pseudostratified ciliated epithelium
H.E. 100X
Basal membrane8
Trachea
Tunica fibro - musculo - cartilaginea
Cartilage rings - hyaline
cartilage 16-20, incomplete,
covered by pericondrium
fibro-elastic tissue - connects
longitudinally tracheal
cartilages
smooth muscle tissue connects free ends of the
cartilage
H.E. 4X
9
Trachea
Tunica fibro - musculo - cartilaginea
Mucosa
Tunica fibro
musculo
cartilaginea
Adventitia
H.E. 10X
10
Trachea - adventitia
•
•
•
•
Loose connective tissue
White adipocytes
Blood vessels
Nerves
11
Trachea - adventitia
mucosa
Tunica fibro
musculo
cartilaginea
adventitia
H.E. 10X
12
Lungs
• covered by visceral pleura
• Intrapulmonary airways:
•
•
lobar bronchi, segmental bronchi,
Pre-terminal bronchioles, terminal bronchioles
– respiratory area
•
•
•
respiratory bronchioles
alveolar ducts
alveolar sacs
• Connective tissue
– around the airway or organizing septa
– blood vessels, lymphatics and nerves
13
Lobar bronchi, segmental bronchi
• Tunica mucosa
• Tunica fibro- cartilaginea
• Adventitia
14
Lobar bronchi, segmental bronchi
• Tunica mucosa
– respiratory epithelium
– lamina propria
•
•
•
•
Elastic fibers with longitudinal distribution
Bundles of muscle fibers spirally oriented
Sero-mucous glands
Lymphoid infiltrates
• Tunica fibro-cartilaginea
• Adventitia
15
Lobar bronchi, segmental bronchi
• Tunica mucosa
• Tunica fibro- cartilaginea
– islands of hyaline cartilage interconnected by
dense connective tissue bands
• Adventitia
16
Lobar bronchi, segmental bronchi
• Tunica mucosa
• Tunica fibro-cartilaginea
• Adventitia
– connective tissue with blood vessels, lymphatics
and nerve fibers
– connects bronchi with blood vessels and alveoli.
17
Lobar bronchi, segmental bronchi
glands
cartilage
Lumen
muscular fiber
H.E. 10x
glands
Segmental bronchus
H.E. 10x
Segmental bronchus
H.E. 10x
20
Pre-terminal bronchiole
•
Mucosa
–
–
–
•
Tunica muscularis
–
•
simple columnar ciliated epithelium with goblet
cells ± Clara cells
lamina propria with elastic fibers (longitudinal) and
lymphoid infiltrates
does not contain glands
bundles of smooth muscle fibers arranged
concentrically
Adventitia
–
Thin layer of loose connective tissue
21
Pre-terminal bronchiole
Muscularis
artery
H.E. 10x
Pre-terminal bronchiole
H.E.20x
23
Terminal bronchiole
• Thin wall, tunics are less well defined
• Mucosa
– Simple cuboidal epithelium (sometimes
ciliated) and Clara cells
– No goblet cells
– Thin lamina propria
• Muscularis
– Smooth muscle bundles arranged in
discontinuous pattern
24
Terminal bronchiole
H.E.10x
Terminal bronchiole
H.E.20x
26
Respiratory bronchiole
• Mucosa
– discontinous epithelium - simple cuboidal
– very thin lamina propria
• Muscularis
– bandles of smooth muscle fibers
27
Respiratory bronchiole
H.E.40x
28
Respiratory bronchiole
H.E.20x
Ducts and alveolar sacs
• alveolar ducts
– tubes delimited by:
• simple squamous epithelium
• rings of smooth muscle cells
• ending in alveolar sacs
• alveolar sacs
– common opening areas of several alveoli
30
Ducts and alveolar sacs
Terminal
bronchiole
Alveolar
Duct
H.E.40x
Pulmonary alveoli
• Detach from the wall of respiratory
bronchioles
– Sac-like structures
• Separated by the ALVEOLAR SEPTUM
32
Pulmonary alveoli
• Two cell types:
• Type I pneumocytes (40%)
– covering 95% of the alveolar surface
– squamous cells
– role in gas exchange
• Type II pneumocytes (60%)
– cover only 5% of the area
– cuboidal
– produce surfactant
Pulmonary alveoli
Pulmonary alveoli
H.E.20x
Alveolar septa
– blood capillaries
– macrophages
– connective tissue cells
– ± pores alveolar
36
Alveolar septa
H.E.40x
37
Alveolar septum
H.E.40x
38