Pulmonary Defense Mechanisms Flashcards
Removal mechanisms in the airways are aimed at?
MINIMIZING inflammation
What are the main defense mechanisms in the upper airways and bronchi?
Anatomic barriers - epithelium
Cough reflex
Mucociliary apparatus
IgA
What are the main defense mechanisms in the alveoli?
Alveolar macrophages
Type 1/2 Alveolar cells, Club cells
Surfactants and opsonins
Neutrophils
What can trigger the cough reflex?
Chemicals, mechanical stimulation, inflammation and voluntary
Describe the events of the cough reflex
- Deep inspiration
- Closure of the glottis to trap the air
- Build up of intrathoracic pressure
- Initiation of expiratory effort
- Sudden release of trapped air at a higher pressure
List 3 airway epithelium functions
- Barrier function
- Defense function - produce cytokines
- Translocate IgA into the mucus at the lumen surface
What size particles can be deposited in the mucus of the upper airways?
Greater than 2-3 micrometers and less than 10 micrometers
What are some things that the mucus contains?
IgA, lysozyme, lactoferrin, peroxidases
What are the 2 layers that the cilia on the airway epithelial cells traverse through to reach the foreign particles?
Sol (aqueous) layer
Mucus (gel) layer
For the mucociliary apparratus, what do the cilia do?
They extend through the sol layer and the mucus layer to propel the foreign particles forward to attempt to expel them
The upper airways also have a LARGE population of TRegs. What do they produce to minimize inflammation?
IL-10 and TGFbeta
What is the alveoli’s first line of defense?
Alveolar macrophages
What type of macrophages are alveolar macrophages and what is their job?
M2 - maintain tolerance
What are the types of surfactant proteins found in the alveoli?
A and D
List some of the jobs that SP-A and SP-D have in the alveolar spaces
- Bind pathogens
- Damage bacterial membranes
- Modulate macrophage phagocytosis
What do alveolar macrophages release to minimize inflammation?
IL-10 and TGFbeta
If/when the acute inflammatory response begins, what cytokines are responsible for increasing the expression of adhesion molecules?
IL-1 and TNF
With the acute inflammatory response, IL-1 and TNF increase adhesion molecules. What cell type slows down, binds to endothelium and enters?
Neutrophils
What chemokine to neutrophils follow?
IL-8
Neutrophils then deploy their ____ to catch bacteria
NETs
If the acute inflammatory response turns to chronic, what cells will infiltrate?
Activated T cells
M1 macrophages
The chronic inflammatory state brings T cells and M1s to the site. It also causes what 2 things?
- Mucus HYPERsecretion
2. Remodeling of tissue – fibrosis
What are the main molecular events that occur during the early phase of a Type 1 Hypersensitivity?
- Cross-link mIgE
2. Degranulation of Mast cells
What are the early phase symptoms of a Type 1 Hypersensitivity?
Sneezing
Pruritis
Rhinorrhea (runny nose)
Congestion
What are the main cells that infiltrate the area during the late phase of a Type 1 Hypersensitivity?
Eosinophils Neutrophils Basophils Th2 lymphocytes MORE mast cells
What are the 2 jobs of the eosinophils in the late phase of the Type 1 Hypersensitivity reaction?
- Pro-inflammation
2. Local tissue damage
What are the late phase symptoms of a Type 1 Hypersensitivity?
Fatigue
Myalgia
Asthma
What 2 things are responsible for chronic asthma remodeling?
Leukotrienes (C4, D4, E4)
Prostaglandins (D2, E2, F2)
With chronic asthma remodeling, leukotrienes cause?
Bronchospasm
Increased permeability
Mucus production
With chronic asthma remodeling, prostaglandins cause?
Bronchospasm
Vasodilation
With chronic asthma remodeling what is deposited in the submucosa?
Collagen - by smooth m. cells and fibroblasts
With COPD, what cytokine causes secretion of more cytokines?
Th17
With COPD, Th17 causes secretion of?
IL-8, IL-17, IL-22
With COPD, Th17 causes secretion of more cytokines that results in infiltration of what cells?
Neutrophils and inflammatory macrophages
Ventilator Associated Lung Injury physical damage?
Over inflation
Mechanical stress
Ventilator Associated Lung Injury biodamage?
Hyper-oxygenation
Free radicals
Increased Neutrophils
With a Ventilator Associated Lung Injury, what do Neutrophil NETs lead to?
Platelet activation and clot formation
Vaping Associated Lung Injury shows ______ on chest X-ray
Bilateral infiltrates
Is there an infection with a Vaping Associated Lung Injury (VALI)?
NO
What can a Vaping Associated Lung Injury turn into?
Lipoid Pneumonia
With is Lipoid Pneumonia?
Pneumonia caused by inhaling lipids
Besides a Vaping Associated Lung Injury, what else can cause Lipoid Pneumonia?
Chronic essential oil use
