03 - Path of treachea and lung

Question 1

(1. Tracheal collapse is most common in what breed dogs? How can radiographs taken at both inspiration and expiration help located the site of collapse?)
1. Tracheal collapse is most common in what breed dogs?
2. How can radiographs taken at both inspiration and expiration help locate the site of collapse?

Answer 1

1. toy and miniature breed dogs
2. inspiratory dyspnea: collapsed cervical (extrathoracic) trachea

expiratory dyspnea: collapsed thoracic (intrathoracic) trachea

Question 2

(2. List the agents of kennel cough complex. Which agent is considered most important in most circumstances?)
1. List the agents (four of them)
2. Which agent is considered most important?

Answer 2

1. bordetella bronchiseptica

canine adenovirus 2

canine parainfluenza

mycoplasma (less often)

2. bordetella bronchiseptica (an extracellular pathogen)

attaches to cilia of respiratory epithelium and releases “tracheal toxin” that induces host cells to produce nitric oxide –> ciliostasis and blunted or denuded cilia

Question 3

(3. What processes and agents can cause necrosis of bronchial and bronchiolar epithelium?)

Answer 3

Bronchiolitis and bronchiolar epithelial necrosis are caused by viral infections, inhalation of toxic gases, toxins that are metabolized by cytochrome P450 in nonciliated Clara cells, hypersensitivity reactions and inflammatory reactions to inhaled irritants.

Question 4

(4. How do bronchi and bronchioles respond to transient injury or persistent injury? What lesions can develop if repair is not complete?)
1. come back to this one

Answer 4

look at bottom of 28 and graph on 29

Question 5

(5. Define Bronchiectasis. What is the pathogenesis? Bronchiectasis can be associated with what types of lung disease?)
1. define it
2. What is pathogenesis?
3. associated with what types of lung disease?

Answer 5

1. permanent dilation of bronchi caused by destruction of muscle and elastic tissue (resulting from chronic bronchial obstruction and infection)
2. bronchus inflammation/infection –> neutrophil-derived proteases and oxygen radical damage epithelium and supportive connective tissue –> weakening of bronchial wall and reduced mucociliary clearance –> pooling of exudates in bronchial lumen –> dilation
3. seqeulla to chronic bronchopneumonia (in cow)

observed in dogs (cockers and poodles) with bacterial infections affecting right cranial or middle lung lobes

lung parasites in pigs, sheep, and goats can cause it

horses with chronic heaves

Question 6

(6. What is the pathogenesis of bovine atypical interstitial pneumonia or fog fever?)

Answer 6

2) Ingested toxins in cattle (e.g., bovine interstitial pneumonia andemphysemia, fog fever, atypical interstitial pneumonia)

i. L-tryptophan (metabolized in rumen to the pulmonary toxin 3-methylindole): cytochrome P450 enzymes in Clara cells  reactive intermediate  necrosis of non-ciliated bronchiolar epithelium (Clara cells), alveolar type I pneumocytes and endothelial cells. Lesions in
both bronchioles and alveoli.

ii. 4-ipomeanol, a contaminant of moldy sweet potatoes  cytochrome P450 enzymes  reactive intermediate  necrosis of Clara cells in bronchioles, type I pneumocytes in alveoli and endothelium. Lesions in both bronchioles and alveoli. Similar to 3-MI.
iii. Low dose- necrosis of bronchiolar epithelium
iv. High dose- pulmonary edema and damage to alveolar septa

Question 7

(7. What are two extracellular bacterial agents (list two genus) that impair activity of cilia?)

1-2. What are they?

Answer 7

1. Bordetella

(bordetella avium and bordetella bronchiseptica)

2. I guess you need to have two genuses… so better find another

Question 8

Answer 8

read on 34 and 35

The lining of the airways in the lungs becomes inflamed in asthma. This reaction causes the airways to narrow and restricts air flow. Corticosteroids reduce inflammation by blocking the action of certain natural chemicals in the body, called prostaglandins, that are normally responsible for triggering the inflammatory response. Reducing inflammation widens the airways and thereby relieves or prevents asthma attacks. When they are used in treating hay fever, corticosteroid drugs act on the lining of the nose to reduce inflammation. In people with sarcoidosis or fibrosing alveolitis, the reduction in inflammation produced by corticosteroid treatment slows down and minimizes damage to lung tissues.

Question 9

Answer 9

read on 34 and 35

The lining of the airways in the lungs becomes inflamed in asthma. This reaction causes the airways to narrow and restricts air flow. Corticosteroids reduce inflammation by blocking the action of certain natural chemicals in the body, called prostaglandins, that are normally responsible for triggering the inflammatory response. Reducing inflammation widens the airways and thereby relieves or prevents asthma attacks. When they are used in treating hay fever, corticosteroid drugs act on the lining of the nose to reduce inflammation. In people with sarcoidosis or fibrosing alveolitis, the reduction in inflammation produced by corticosteroid treatment slows down and minimizes damage to lung tissues.