Histology 11: Nsu Spring 2009 Taken By: Gregory Rodocker

Histology 11 NSU Spring 2009 Taken by: Gregory Rodocker

The Respiratory System 

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Lungs and a ventilatory mechanism to move air into and out of the lungs Lung are composed of the 

Conducting portions  



Conduct air Condition air

Respiratory portion 

alveoli

Pathway  

Nasal orifice/Nares/Nostrils Vestibule 

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Transition to Respiratory Epithelium

Fossae  

Lined mostly with Respiratory Epithelium Uppermost reaches lined with Olfactory Epithelium

Respiratory Epithelium 

   

Pseudostratifed ciliated columnar epithelium Goblet (mucous) cells Brush cells Basal cells Small granule cells

Olfactory Epithelium   

Supportive cells Basal cells Olfactory cells  

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Sensory cells Non-motile cilia

Bowman glands

Respiratory epithelium  

Ciliated pseudostratified epithelium Rich with mucous goblet cells 



Collectively known as the respiratory epithelium

Also contains  

Basal cells - regenerative Brush cells - sensory

Trachea 





Mucosa composed of typical respiratory epithelium Also, is an underlying set of C-shaped cartilage rings and seromucous glands that produce a more watery mucous. Open portion closed by smooth muscle and fibroelastic tissue

Bronchi 

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There are a pair of primary bronchi Each one branches dichotomously 9-12 times a cartilage network keeps the lumen open for airflow

Bronchiole   

Airways less than 5 mm No cartilage No glands other than goblet cells 

No submucosal glands

Respiratory bronchiole and alveolus 



Region of transition from conducting to respiratory portions Alveoli  

200 um in diameter Arranged along and around alveolar ducts and sacs

Cells composing an alveolus 

Type I alveolar cell 

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Type II alveolar cell  

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Or squamous alveolar cell Produce surfactant Serve as basal cells to replace themselves and type I cells

Alveolar macrophages 

Dust cells

What surfactant does

Type II alveolar cell

Pathology - Emphysema 

Emphysema victims are referred to a fighters as they adopt strategies that allow continued successful ventilation long into the disease process. Emphysema is an actual loss of lung tissue caused by chronic irritation by pollutants or lack of ά1-Anti-trypsin or both.

Barrel Chest caused by Emphysema

Pathology - Emphysema 

Emphysema is classically of two types by region of tissue destroyed.  

Centrilobular or centroacinar Panlobular or panacinar

Gross emphysematous Lung 

Note the open appearance of the lung tissue.

Emphysematous lung section

Pathology 

Certain genetic or reactive abnormalities are associated with impaired ciliary function (ciliary dyskinesia syndromes), and may predispose patients to sinusitis, bronchiectasis, and male infertility (immotile sperm)



Chronic irritation of the respiratory mucosa produces hyperplasia of these glands (increased Reid ratio) and an increased ratio of mucus-secreting to serous cells