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Respiratory System General Introduction - Pathology (view source)
Revision as of 17:33, 8 November 2012
, 17:33, 8 November 2012no edit summary
==Invasion of respiratory system==
==Invasion of respiratory system==
===Transcoelomic===
===Transcoelomic===
*Infection via extension from pleura or mediastinum, or traumatic penetration from chest wall (e.g. bite), diaphragm (e.g. [[Forestomach - Inflammation#Traumatic Reticulitis|bovine traumatic reticulitis]]) or oesophagus (e.g. foreign body).
*Infection via extension from pleura or mediastinum, or traumatic penetration from chest wall (e.g. bite), diaphragm (e.g. [[Traumatic Reticulitis|bovine traumatic reticulitis]]) or oesophagus (e.g. foreign body).
==[[General Pathology - Healing and Repair#Repair in the Respiratory Tract|Repair in the respiratory tract]]==
==[[Healing and Repair - Pathology#Repair in the Respiratory Tract|Repair in the respiratory tract]]==
**Maxillary sinus opening very large - 'maxillary recess'
**Maxillary sinus opening very large - 'maxillary recess'
***Maxillary sinus infections very uncommon in carnivores
***Maxillary sinus infections very uncommon in carnivores
**Highly developed in [[Hindgut Fermenters - Horse - Anatomy & Physiology|horses]]
**Highly developed in [[Alimentary System - Horse Anatomy|horses]]
**Slit-like, high openings in horses
**Slit-like, high openings in horses
**Predisposed to bacterial infections
**Predisposed to bacterial infections
===Trachea===
===Trachea===
[[Image:Trachea epithelium.jpg|right|thumb|100px|<small><center>Epithelium of trachea (Courtesy of RVC Histology Images)</center></small>]]
[[Image:Trachea epithelium.jpg|right|thumb|100px|<small><center>Epithelium of trachea (Courtesy of RVC Histology Images)</center></small>]]
*Most domestic animals - pseudostratified epithelium, ciliated, non-ciliated and mucous cells
*Most domestic animals - pseudostratified epithelium, ciliated, non-ciliated and mucous cells
**Coughing
**Coughing
**Bronchial associated lymphoid tissue (BALT) covered by M cells (microfold cells) where there is professional APC and lymphocytes trafficking.
**Bronchial associated lymphoid tissue (BALT) covered by M cells (microfold cells) where there is professional APC and lymphocytes trafficking.
*The lung receives half of the cardiac output and must rapidly exchange gases with this large blood volume through a vast alveolar membranous surface
*The lung receives half of the cardiac output and must rapidly exchange gases with this large blood volume through a vast alveolar membranous surface
*This makes the lung vulnerable to circulatory disturbances, most notably [[Lungs Circulatory - Pathology#Pulmonary oedema|pulmonary oedema]]
*This makes the lung vulnerable to circulatory disturbances, most notably [[Pulmonary Oedema|pulmonary oedema]]
*Normally, mechanisms are in place to protect the lung from the entry of circulatory fluid into alveolar spaces
*Normally, mechanisms are in place to protect the lung from the entry of circulatory fluid into alveolar spaces
*The net effect is that liquid moves from the alveolar interstitum towards lymphatics in the fascia and then the hilus of the lung and mediastinum
*The net effect is that liquid moves from the alveolar interstitum towards lymphatics in the fascia and then the hilus of the lung and mediastinum
*Prevents dessication of the mucosal epithelium
*Prevents dessication of the mucosal epithelium
*Contains antimicrobial substances
*Contains antimicrobial substances
*Immunoglobulin - IgA
*Immunoglobulin - [[IgA]]
**IgA produced by mucosal plasma cells
**[[IgA]] produced by mucosal plasma cells
**IgA can attach to specific pathogen antigens (viruses, bacteria) trapping them in the mucus for clearance
**[[IgA]] can attach to specific pathogen antigens (viruses, bacteria) trapping them in the mucus for clearance
*Lysosyme
*Lysosyme
**Direct action on bacterial cell walls
**Direct action on bacterial cell walls
*This mucous blanket is contributed to by the secretions of the Clara cells in the terminal and respiratory bronchioles
*This mucous blanket is contributed to by the secretions of the Clara cells in the terminal and respiratory bronchioles
*Also contained in these secretions in the respiratory tract are: IgA, IgG, and Interferon
*Also contained in these secretions in the respiratory tract are: [[IgA]], [[IgG]], and Interferon
*At all levels of the tract, and especially at bifurcations, there are subepithelial leukocytes which have the potential to develop into lymphoid follicles under a persistent antigenic challenge
*At all levels of the tract, and especially at bifurcations, there are subepithelial leukocytes which have the potential to develop into lymphoid follicles under a persistent antigenic challenge
*Phagocytes resident within the alveolus
*Phagocytes resident within the alveolus
*There is normally one sentinel macrophage per alveolus and they ingest particles which reach the alveolus
*There is normally one sentinel macrophage per alveolus and they ingest particles which reach the alveolus
*When activated by such irritants, they have increased phagocytic and bactericidal capability and are able to recruit further [[Macrophages - Anatomy & Physiology|macrophages]] ([[Monocytes - Anatomy & Physiology|monocytes]] from the blood), and also to attract [[Neutrophils - Anatomy & Physiology|neutrophils]] and other [[Leukocytes - Anatomy & Physiology|leukocytes]] to the site
*When activated by such irritants, they have increased phagocytic and bactericidal capability and are able to recruit further [[Macrophages|macrophages]] ([[Monocytes|monocytes]] from the blood), and also to attract [[Neutrophils|neutrophils]] and other [[Leukocytes|leukocytes]] to the site
*Removal of phagocytosed irritants may be via the mucociliary escalator or carried to the interstitium for sequestration in the connective tissue
*Removal of phagocytosed irritants may be via the mucociliary escalator or carried to the interstitium for sequestration in the connective tissue
*Sneezing
*Sneezing
*Coughing
*Coughing
[[Category:Respiratory System - Pathology|A]]