LUNG INFECTION 2

Question 1

Host defense mechanism of nasopharynx

Answer 1

Nasal hair
Turbinates
Mucociliary apparatus
Immunoglobulin A (IgA) secretion

Question 2

Host defense mechanism of oropharynx

Answer 2

Saliva
Sloughing of epithelial cells
Local complement production
Interference from resident flora

Question 3

Trachea, bronchi

Answer 3

Cough, epiglottic reflexes
Sharp-angled branching of airways
Mucociliary apparatus
Immunoglobulin production (IgG, IgM, IgA)

Question 4

Host defense mechanism of Terminal airways, alveoli

Answer 4

Alveolar lining fluid (surfactant, Ig, complement, fibronectin)
Cytokines (interleukin 1, tumor necrosis factor)
Alveolar macrophages
Polymorphonuclear leukocytes
Cell-mediated immunity

Question 5

Compromise In Pulmonary Host Defense Mechanism

Answer 5

Loss of suppression of cough reflex
• Coma, anaesthesia, neuromuscular disorders, drugs, postsurgery, chest pain
Injury to mucociliary apparatus
• Impairment of ciliary function, destruction of ciliated epithelium
due to cigarette smoke, inhalation of hot or corrosive gases, viral
diseases or immotile cilia syndromes
Interference with phagocytic action of alveolar macrophages
• Alcohol, tobacco smoke, anoxia, oxygen intoxication
Pulmonary congestion and oedema
Accumulation of secretions
• Cystic Fibrosis and bronchial obstruction