Veterinary Histology UFF
Department of Morphology - Biomedic Institute
LaBEc - Laboratory of Cellular and Extracellular Biomorphology 		 
Veterinary Histology Atlas
    Versão em Português
Introduction
Respiratory System

Basic Mechanism

Respiration
• Movement of the air in and out of the lungs (ventilation)
• Supplies oxygen to the cells and eliminates carbon dioxide

Division
Conducting Portion of the Respiratory System

 

Nasal Cavity

• Anterior Portion or Vestibule: Covered by Skin and present vibrissae
• Posterior Portion: Lined by a pseudostratified ciliated columnar epithelium with goblet cells
• Olfactory Region: The top of the nasal cavity is lined by olfactory epithelium

The olfactory epithelium is made up of:
• Olfactory Cells
• Sustentacular Cells
• Basal Cells

 

 

• Pseudostratified ciliated columnar epithelium with goblet cells.

Pharynx

Subdivided into three regions:
• Upper Nasopharynx: Lined by pseudostratified ciliated columnar epithelium with goblet cells
• Middle Oropharynx: Lined by Stratified non-keratinized squamous epithelium
• Lower Laryngopharynx: Lined by Stratified non-keratinized squamous epithelium

Larynx

• Responsible for the phonation
• Lined by pseudostratified ciliated columnar epithelium
• Presence of the epiglottis (elastic cartilage):
Prevents the entrance of liquids and solids into the respiratory system during deglutition.

Trachea

• We find 16 to 20 pieces of cartilage (hyaline) with a horse-shoe shape
• From the inside out we find the:

Mucosa
• Pseudostratified ciliated columnar epithelium with goblet cells
• Lamina propria formed by loose connective tissue rich in elastic fibers
• We find mucous and serous acinar glands


Submucosa
• Between the mucosa and the cartilage
• Presents a great amount of elastic fibers
• Presence of numerous blood vessels

Adventitia: Loose connective tissue

Bronchial Tree

Extrapulmonary bronchi : Identical to the trachea

Intrapulmonary bronchi
• The C rings are substituted by irregular plates of cartilage
• There are two layers of smooth muscle separating the lamina propria from the submucosa

Bronchioles
Lining epithelium is variable
• Pseudostratified ciliated columnar with goblet cells
• Simple ciliated columnar with goblet cells
• Lamina propria with no glands and surrounded by layers of smooth muscle.
Do not possess cartilage. Protect and regenerate the bronchial epithelium
Terminal Bronchioles

• Cubic cells with a few cilia
• Possess Clara cells(secretors)
• Lamina propria of connective tissue surrounded by smooth muscle cells

 

Epitélio Bronquíolo Terminal e Respiratório

• Cubic cells with a few cilia
• Possess Clara cells (secretors)
• Lamina propria of connective tissue surrounded by smooth muscle cells

 

Respiratory Portion of the Respiratory System

Respiratory bronchioles
• Similar to the terminal bronchioles
• Have their walls interrupted by alveoli

Epithelium of Respiratory Bronchiole
• Simple cuboidal epithelium

Alveolar Ducts
• Are alveoli in linear arrangements
• End in alveolar sacs

Alveoli
• Have very thin walls
• Allow the exchange of CO2 for O2
• The walls of the alveoli have:

Type I pneumocytes: Constitute the squamous epithelium

Type II pneumocytes:
• Cubic Cells
• Secrete pulmonary surfactant (Reduces the surface tension and avoids the collapse of the alveolus)

Alveolar macrophages: Dust cells that perform phagocytosis

Pleura
• Serosa membrane, Connective tissue plus Meothelium.
Credits
Tissues
Epithelial
Connective
Cartilaginous
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Circulatory
Blood
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Digestive
Accessory Gls.
Respiratory
Integumentary
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Female Reprod.
Birds Histology
Quiz
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Bibliography