3. SKELETAL MUSCLES AND BONES ARE REQUIRED
FOR RESPIRATORY SYSTEM FUNCTION
RIBS
STERNUM
INTERCOSTAL MUSCLES
DIAPHRAGM
4. GENERAL ORGANIZATIONAL PATTERN
OF CONDUCTING PORTION
OF RESPIRATORY SYSTEM
MUCOSA
Luminal sheet epithelium
(typically “respiratory epithelium”)
Lamina propria (loose FECT)
SUBMUCOSA (mod. dense FECT)
(not always present or merged
with lamina propria, serous or mixed glands may
be present in the lamina propria or submucosa)
“MUSCULARIS” EXTERNA (may be smooth
muscle, cartilage, or bone)
ADVENTITIA or SEROSA (absent in nasal cavity)
5. CELL TYPES FOUND IN
“RESPIRATORY EPITHELIUM”
PREDOMINANT CELL TYPES
Ciliated columnar cells – move
mucus
Goblet cells – secrete mucus
Basal cells – replace damaged cells
LESS COMMON CELL TYPES
Brush cells – sensory receptor cells
Dense core granule cells (Small granule
cells) – enteroendocrine cells
Clara cells (trachea and bronchi) – protein
secreting cells, secrete surfactant
6. PREDOMINANT CELL TYPES
FOUND IN “RESPIRATORY EPITHELIUM”
Ciliated columnar cell Goblet cell (Mucous cell)
Basal cell
Source: Lentz. 1971. Cell Fine Structure.
10. EPITHELIA OF REGIONS WITHIN
NASAL CAVITIES
VESTIBULE or
OLFACTORY
NOSTRIL SEGMENT
Stratified squamous
sheet epithelium
RESPIRATORY
SEGMENT
RESPIRATORY
SEGMENT
”Respiratory NOSTRIL
epithelium”
OLFACTORY
SEGMENT
Olfactory
epithelium
11. NASAL CAVITIES/ NASAL PASSAGEWAYS
OEp = olfactory
epithelium
OM = olfactory
mucosa
Rep = “respiratory
epithelium”
EB = bone
Source: Plate 88, Figure 1 in Ross et al. 1995. Histology. A Text and Atlas. 3rd Edition.
12. CELL TYPES FOUND IN
OLFACTORY EPITHELIUM
Sustentacular or
supporting cells
Olfactory cells
Basal cells
Brush cells
14. Mucosa of the Olfactory Segment
of the Nasal Cavity
SC = supportive
cells
OC = olfactory
neuron cell bodies
BC = basal cells
BG = olfactory
glands (serous)
N = peripheral
nerves
V = blood vessels
C = capillaries
Source: Plate 88, Figure 2 in Ross et al. 1995. Histology. A Text and Atlas. 3rd Edition.
15. NASAL CAVITIES/NASAL PASSAGEWAYS
are separated from oral cavity by PALATE
OLFACTORY
SEGMENT
RESPIRATORY
SEGMENT
NOSTRIL
HARD PALATE SOFT PALATE
Modified from: Figure 18.1 in Ross et al. 1995. Histology. A Text and Atlas. 3rd Edition.
16. SOFT PALATE
NASAL
ORAL CAVITY
CAVITY side
side
“Respiratory epithelium”
of Nasal Mucosa
Source: Hammersen. 1980. Histology.
17. PHARYNX
”Respiratory
epithelium”
Stratified squamous
sheet epithelium
Modified from: Figure 18.1 in Ross et al. 2003. Histology. A Text and Atlas. 4th Edition.
20. EPIGLOTTIS of LARYNX
Stratified squamous
epithelium
Elastic Cartilage
Stratified squamous
or pseudostratified
columnar epithelium
Source: Hammersen. 1980. Histology. A Color Atlas of Cytology, Histology and Microscopic Anatomy. 2nd Edition.
21. LARYNX
Epiglottis
Stratified squamous
sheet epithelium
Ventricular fold/
false vocal cord
Vocal fold/
true vocal cord
Pseudostratified ciliated
columnar sheet epithelium
Source: Hammersen. 1980. Histology. A Color Atlas of Cytology, Histology and Microscopic Anatomy. 2nd Edition.
22. LARYNX
Epiglottis
Cartilaginous plate in
“Muscularis” Externa
Intrinsic glands in
Lamina propria of
Striated skeletal Mucosa
muscle tissue in
“Muscularis” Externa
Vocal ligament
Vocalis muscle
Cartilaginous plate in
“Muscularis” Externa
Source: Hammersen. 1980. Histology. A Color Atlas of Cytology, Histology and Microscopic Anatomy. 2nd Edition.
40. Intrapulmonary Bronchi
Mucosa
“Respiratory” epithelium (+/- Clara cells)
Lamina propria of loose FECT
“Muscularis”
Spiral bundles of smooth muscle
Submucosa
Loose to occasionally moderately dense FECT,
may contain compound tubuloacinar glands
“Muscularis”externa
Hyaline cartilages (horseshoe-shaped “rings”)
Smooth muscle across open ends of cartilages
Moderately dense FECT connects adjacent rings
Adventitia
Loose FECT
41. INTRAPULMONARY BRONCHUS
Mucosa
Bronchiole
branching off
of bronchus Intrinsic glands in
Lamina Propria
FECT
Cartilaginous plate in
“Muscularis” Externa
Source: Jungueira et al. 1975. Basic Histology. 4th Edition.
43. BRONCHIOLES
<1 mm in diameter
No cartilage in wall
MUCOSA
Luminal sheet epithelium
(ranges from pseudostratified
ciliated columnar in large
bronchioles to simple
cuboidal with mixed ciliated
and Clara cells in terminal
bronchioles)
Lamina propria = loose FECT
“MUSCULARIS” = bundles of
PULMONARY LOBULE smooth muscle
Source: Leeson & Leeson. 1981. Histology. 4th Edition.
45. CELL TYPES FOUND IN
LUMINAL EPITHELIUM OF BRONCHIOLES
Ciliated cell Clara cell Ciliated cell
Ciliated cells
Basal cells
Goblet cells
Brush cells
Small granule cells
Clara cells
Source: Ross et al. 1995. Histology. A Text and Atlas. 3rd Edition.
50. ALVEOLI (AIR SPACES)
Occur in the walls of
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
CONSIST OF:
Alveolar Epithelium
Thin region of
highly vascularized FECT
ad = alveolar duct
as = alveolar sac
a = alveolus Source: Leeson & Leeson. 1981. Histology. 4th Edition.
51. CELL TYPES FOUND IN
ALVEOLAR EPITHELIUM
Type I Pneumocytes [gas exchange]
Type II Pneumocytes [secrete
surfactant (mix of proteins and lipids)]
Brush Cells [sensory receptors]
Pulmonary Macrophages
[phagocytosis]
52. CELL TYPES FOUND IN
ALVEOLAR EPITHELIUM
(as observed at TEM level)
Type I Pneumocyte Type II Pneumocyte
(and adjacent capillary)
Source: Lentz. 1971. Cell Fine Structure.
57. CELL TYPES
FOUND IN
ALVEOLI
(as observed at the LM level)
In addition to Type I and Type
II alveolar cells
(pneumocytes), macrophages
are frequently observed
migrating along the alveolar
surface. Macrophages are
frequently detached from the
surface during processing.
58. Criteria for Classifying Intrapulmonary Structures
Structure Lining Epithelium Other Features
Bronchi pseudostratified hyaline cartilage in wall
columnar usually + smooth muscle
Bronchioles pseudostratified no hyaline cartilage in wall
columnar to smooth muscle present
simple cuboidal,
no squamous
Respiratory >50% cuboidal or little or no smooth muscle,
Bronchioles columnar, <50% usually some loose FECT
squamous (but
squamous present)
Alveolar Ducts <50% cuboidal, no smooth muscle, loose
Alveolar Sacs >50% squamous FECT sparse or absent
59. ALVEOLI & BRONCHIOLES
TB = terminal bronchiole
RB = respiratory bronchiole
AD = alveolar duct
AS = alveolar sac
