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RespiratorySystem
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Structure
Consists of:
Lungs
Conducting part
Respiratory part
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Functions
It serves the following functions:
Conduit of air
Gas exchange
Endocrine function
Acid-base balance
Phonation
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Respiratory Epithelium
Most of the respiratory system is linedby typicalrespiratoryepithelium:
1. Cilaiated columnar epithelium
2. Mucus goblet cells
3. Brush cells
4. Basal cells
5. Granular cells
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Nasal cavity
Consists of
Vestibule:
sweat glands, sebaceous glands, vibrissae
Nasal fossa:
Conchae gives ribbon-like passage
Swell bodies
Complex vascular organization
Olfactory epithelium:
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Trachea
Lined by typical respiratory epithelium
Contains 16-18 c-shaped cartilages
Fibroelastic band bridges the open ends of c-
shaped cartilages
Smooth muscle fibers (Trachialis) also foundin the same place
Numerous seromucus glands
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Bronchus
It is 5 mm or more in diameter
Lined by respiratory epithelium
Plates of cartilage in lamina propria
Smooth muscle layer
Elastic fibers
Seromucus glands
Lymphocytes and
lymphatic nodules
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Bronchiole
They are
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Alveolar Duct
When respiratory bronchiole is totally replaceby alveolar openings
Each alveolar duct opens into atria
Each atrium opens into two or more alveoli
Complex network of elastic and reticular fiberssurrounding the opening of atria, sacs andalveoli
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Alveoli
They are sac like evagination of respiratory
bronchiole, alveolar duct, alveolar sac It is 200 mm in diameter
Alveolar wall
Interalveolar septum Type I cells (Squamous alveolar)
Type II cells
Lung macrophage Air-blood barrier
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