Respiratory Disorders Flashcards
What are the respiratory systems primary functions?
Gas exchange between atmosphere and blood, protection from inhaled pathogens and irritants, regulation of body pH, also vocalization/phonation
What structures make up the upper airways?
Nasal cavity, pharynx, larynx (above the vocal cords)
What structures make up the lower airways?
Larynx (portion below vocal cords), trachea, bronchi, bronchioles, alveoli
What is the mucociliary apparatus?
Located on larger airway portions, cilia on epithelium function to move mucus secreted by goblet cells up towards larynx to be removed
What is surfactant?
Phospholipid substance secreted by type II alveolar cells, lines alveoli to decrease surface tension, make it easier to inflate the lungs
What are the four steps of gas exchange?
Ventilation of the lungs, diffusion of oxygen from the alveoli into the capillary bed, perfusion of systemic capillaries with oxygenated blood, diffusion of oxygen from systemic capillaries into the cells
Is expiration a passive or active process?
Passive- but can become active when there is resistance or someone is trying to breathe at maximum capacity
What is the average V/Q ratio for lungs?
0.8, indicates the rate of blood flow across the alveoli is greater than the rate of ventilation
What would a high V/Q ratio indicate?
Not enough perfusion of a well-ventilated area, can occur in the apex of the lung or when pulmonary vessels are occluded
What would a low V/Q ratio indicate?
Not enough ventilation of a well-perfused area, can occur in base of lung, or with airway narrowing or obstruction
What is the role of the pulmonary aterioles?
Try to relax/constrict to direct blood to the ventilated areas
What is obstructive lung disease?
Causes difficulty on expiration, results in air trapping/dyspnea/SOB
What disorders are examples of obstructive lung disease?
Asthma, COPD, cystic fibrosis
What is restrictive lung disease?
Prevents lungs from fully expanding and interferes with proper inspiration
Which disorders are examples of restrictive lung disease?
Intrinsic (interstitial lung disease, adverse drug reaction) or extrinsic mechanisms (chest wall and neuromuscular disorders such as ALS, myasthenia gravis), interstitial lung disease (pneumonia, fibrosis, etc.) or injuries (obesity, scoliosis)
What differentiates asthma from other obstructive lung diseases?
Reversibility of obstruction (spontaneous or with treatment)
In general, what type of hypersensitivity reaction is asthma?
Type 1
Which interleukins do Th2 cells secrete in asthma?
IL-4, IL-5, IL-8, and IL-14
What is the role of IL-4?
Helps B cells differentiate into plasma cells, promotes class switching from IgG to IgE
What is the role of IL-5 in asthma?
Aids in recruitment of eosinophils
What is the role of IL-13 in asthma?
Enhances the secretion of fibroblasts, contributes to bronchoconstriction, works with IL-4 to cause IgE class switch
What type of response do Th1 cells cause?
Cell-mediated response (T cells)
What type of response do Th2 cells cause?
Humoral (B cells, antibodies)
What occurs in the late response of asthma?
Recruitment of eosinophils, basophils, neutrophils, macrophages and Th2 cells, occurs 4-8 hours after attack and can persist/be severe
What are leukotrienes?
Released along with histamine in late asthma response (have longer response), result in bronchoconstriction, recruitment of neutrophils and eosinophils, mucus secretion
What do eosinophils do?
Release pro-inflammatory cytokines and cytotoxic mediators–promote vascular leakage, mucus hypersecretion, bronchoconstriction, and airway hyperresponsiveness
What are the two phenotypes of COPD?
Chronic bronchitis and emphysema
What is the number one risk factor for COPD?
Exposure to tobacco smoke
What is primary emphysema?
Caused by inherited mutation in A1-antirypsin gene, usually found in young non-smokers
What is A1-antitrypsin?
Protects lung tissue from proteolytic enzymes that break down elastic (released from immune cells)
What is emphysema?
Chronic inflammatory condition characterized by abnormal permenant enlargement of gas-exchange airways accompanied by destruction of alveolar walls without obvious fibrosis
What promotes airway inflammation in emphysema?
Inspired airway irritants
What is chronic bronchitis?
Moreso inflammation of the bronchi vs. destruction of the alveoli, characterized by hypersecretion of mucus and a chronic, productive cough
Alveolar destruction and air trapping result in what?
V/Q mismatch which results in hypoxia and hypercapnia, can lead to structural changes in pulmonary vasculature (including thickening of tunica intima and vascular smoother muscle hyperplasia)
What is cor pulmonale?
More often seen with chronic bronchitis and is known as R sided HF secondary to pulmonary artery hypertension= hypertrophy of RV,
What are typical causes of acute COPD exacerbations?
Viral culprits (RSV, influenza) mainly, sometimes bacterial
What are the subtypes of non-small cell lung cancer?
Squamous cell carcinoma (30%), adenocarcinomas (35-40%), large cell carcinomas (10%)
What are the characteristics of squamous cell carcinomas?
Arise in large airways, have non-productive cough and hemoptysis, remain well localized and metastasize later on, can cause obstruction
What are the characteristics of adenocarcinoma?
Peripherally located, common in NON-smokers, can be asymptomatic
What are the characteristics of large cell carcinoma?
Centrally located, tumor cells large/undifferentiated, grows rapidly and metastasizes early, poor prognosis, diagnosed by exclusion (d/t non specific nature)
What are the characteristics of neuroendocrine tumors/ small cell carcinomas?
15% of lung cancers, centrally located, correlation with cigarette smoking, metastasize early and spread rapidly, arise from neuroendocrine cells**, poor prognosis
Is latent TB infectious?
No
What is important to consider about the TB skin test?
Cannot differentiate b/t active and latent disease, produces type IV hypersensitivity if individual has ever been exposed
What is the most common etiologic agent of pneumonia?
S. Pneumoniae (community acquired), P. Aeruginosa (HAP) and P. Jirovecii (in immunocompromised)
What is the first point of contact in pneumonia?
Alveolar macrophages
What is tidal volume?
Amount of air that moves in/out of the lungs
Where is respiratory smooth muscle found?
In conducting airways (structures outside of lungs)
How is air expelled from alveoli?
Through elastin
What covers the lungs?
Visceral pleura
What lines the inside of the thoracic cavity?
Parietal pleura
What organs does cystic fibrosis affect?
Airways, digestive tract, and reproductive organs
What are the effects of cystic fibrosis on the lungs?
Mucus plugging (increased numbers and size of goblet cells, alteration of mucus, and impaired mucociliary clearance) , chronic inflammation, chronic infection of small airways
Why is the mucus in CF dehydrated and viscous?
Defective chloride secretion, excess sodium absorption
Which immune cell is present in great numbers in CF?
Neutrophils–release damage oxidants and proteases (ex: elastase)= airway remodelling, bronchiectasis
What are the typical diagnostic measures for CF?
Hx of CF in sibling, + newborn screen and lab evidence of abnormality in CFTR gene, immunoreactive trypsinogen blood test and sweat chloride test
