Chapter 5 Pathos

Q1: What are the two divisions of the respiratory system?

• Air-conducting division: Nose, mouth, trachea, bronchi, bronchioles (delivers air).

• Gas-exchange division: Alveoli and capillaries (diffusion of O₂ and CO₂).

Q2: What structures protect the respiratory system from infection?

Mucus, cilia, and immune cells (IgA) trap and destroy pathogens. The epiglottis prevents aspiration of food into the lungs. Nasal capillaries warm and humidify air

Q3: Which bronchus is more prone to aspiration and why?

The right bronchus is shorter, wider, and more vertical, so foreign particles more easily enter it

Q4: What factors can decrease gas exchange?

↓ Ventilation, ↓ alveolar surface area, ↑ membrane thickness, ↑ interstitial fluid, ↓ perfusion — all reduce diffusion efficiency

Q5: What is the normal ventilation/perfusion (V/Q) ratio?

Ideal ratio = 0.8 (Ventilation = 4 L/min; Perfusion = 5 L/min).
Effective gas exchange depends on alveolar surface area and capillary blood flow

Q6: What is surfactant, and what is its role?

A lipoprotein produced by alveolar cells; it reduces surface tension in alveoli, preventing collapse and making inflation easier

Q7: What controls breathing?

The medulla oblongata (brainstem) — contains:

• Chemoreceptors (sense CO₂ levels).

• Stretch receptors (sense lung fullness).
  Breathing is mostly involuntary, with inspiration as an active process and expiration as passive

Q8: Define compliance, surfactant, and elastic recoil.

• Compliance: Ease of lung expansion; loss = stiff lungs.

• Surfactant: Decreases surface tension to aid inflation.

• Elastic recoil: Ability of lungs to return to original size during exhalation

Q9: What increases airway resistance?

Narrowed lumen, increased mucus, inflammation, or thick air (viscosity).
↑ Resistance = ↑ work of breathing

Q10: What are the differences between diffusion, ventilation, and perfusion?

• Diffusion: Movement of gases across alveolar-capillary membrane.

• Ventilation: Movement of air in/out of lungs (pressure-based).

• Perfusion: Blood flow through pulmonary circulation

Q11: What are normal ABG values?

• pH: 7.35–7.45

• PaO₂: 75–100 mmHg

• PaCO₂: 35–45 mmHg

• HCO₃⁻: 22–26 mEq/L

• O₂ Sat: 95–100%

Q12: Define hypoxia, hypocapnia, and hypercapnia.

• Hypoxia: Low oxygen.

• Hypocapnia: Low CO₂.

• Hypercapnia: High CO₂

Q13: What are the main lung volumes?

• Tidal Volume (TV): 500 mL (normal breath).

• Inspiratory Reserve (IRV): 2–3 L.

• Expiratory Reserve (ERV): 1–1.5 L.

• Vital Capacity (VC): TV + IRV + ERV.

• Residual Volume (RV): 1–1.5 L (air left after exhalation)

Q14: What are Pulmonary Function Tests (PFTs)?

They measure lung volumes (e.g., FEV₁, FVC) to assess airway obstruction and capacity

Q15: What causes infectious rhinitis (common cold)?

Usually viral (rhinovirus), highly contagious, spread via droplets.
Manifestations: Sneezing, congestion, cough, sore throat, mild fever, headache.
Treatment: Rest, fluids, antipyretics, decongestants; antibiotics only if bacterial

Q16: What is influenza?

A viral respiratory infection that affects upper/lower tract.

• Type A: Most severe/common.

• Type B: Less severe.

• Type C: Mild outbreaks.
  Incubation: 1–4 days.
  Symptoms: Fever, cough, body aches, fatigue, congestion.
  Prevention: Handwashing, vaccination

Q17: What is acute bronchitis?

Inflammation of tracheobronchial tree; causes: viral, bacterial, or irritants.
Symptoms: Cough (wet/dry), dyspnea, wheezing, mild fever.
Treatment: Rest, fluids, bronchodilators, cough suppressants

Q18: What is pneumonia?

Infection of alveoli causing inflammation and consolidation.
Types:

• Lobar: Single lobe.

• Bronchopneumonia: Multiple lobes.

• Interstitial: Viral or atypical (between alveoli).
  Causes: Bacteria (esp. Streptococcus pneumoniae), viruses, aspiration

Q19: What are pneumonia complications and treatments?

Complications: Pulmonary edema, sepsis, ARDS.
Treatment: Antibiotics (if bacterial), bronchodilators, oxygen, hydration, rest

Q20: What is tuberculosis (TB)?

Chronic infection by Mycobacterium tuberculosis.
Primary TB: Dormant, may form granulomas.
Secondary TB: Reactivation → symptoms (cough, hemoptysis, night sweats, fever, weight loss).
Diagnosis: Mantoux test, chest X-ray, sputum culture.
Treatment: 6+ months of combination antibiotics

Q21: What is asthma and what causes it?

Chronic, reversible airway obstruction due to inflammation and bronchoconstriction.
Triggers: Allergens, infections, cold air, stress, exercise, smoke

Q22: Describe extrinsic vs. intrinsic asthma.

• Extrinsic: Allergic; IgE-mediated, common in children.

• Intrinsic: Non-allergic; triggered by infections, pollutants, exercise

Q23: What are the stages of an asthma attack?

• Stage 1: Bronchospasm (minutes).

• Stage 2: Airway edema & mucus production (hours) → air trapping.
  Symptoms: Wheezing, SOB, chest tightness, cough, anxiety

Q24: What is status asthmaticus?

A severe, prolonged, life-threatening asthma attack unresponsive to treatment → respiratory failure

Q25: How is asthma diagnosed and treated?

• Dx: PFTs, ABGs, allergen testing.

• Tx: Bronchodilators, corticosteroids, beta agonists, trigger avoidance

Q26: What is COPD?

Progressive, irreversible airway obstruction (includes chronic bronchitis & emphysema).
Causes: Smoking, pollution, irritants.
Effects: Hypoxia, hypercapnia, possible cor pulmonale

Q27: What defines chronic bronchitis?

Productive cough ≥3 months for ≥2 consecutive years.
Patho: Inflammation, mucus hypersecretion, loss of cilia, airway thickening

Q28: What are signs and complications of chronic bronchitis?

• Cyanosis (“Blue bloater”)

• Hypoxemia, hypercapnia, edema, wheezing

• Polycythemia due to chronic hypoxia

• Risk for respiratory infections

Q29: How is chronic bronchitis treated?

O₂ (limited), bronchodilators, corticosteroids, hydration, antibiotics, chest physiotherapy

Q30: What is emphysema and what causes it?

Destruction of alveolar walls → enlarged air spaces, air trapping, and loss of elastic recoil.
Causes: Smoking, enzyme deficiency

Q31: What are symptoms of emphysema?

• Dyspnea, tachypnea

• Barrel chest (AP ratio 1:1)

• Diminished breath sounds

• “Pink puffer” appearance

Q32: Differentiate between chronic bronchitis and emphysema.

Feature	Chronic Bronchitis	Emphysema
Color	Cyanotic (“blue bloater”)	Pink (“pink puffer”)
Sputum	Copious	Minimal
ABG	Hypoxemia + hypercapnia	Mild hypoxemia
Chest	Normal	Barrel-shaped
Breath Sounds	Wheezing, rhonchi	Diminished

Q33: What is atelectasis?

Collapse of alveoli, preventing gas exchange

Q34: What causes atelectasis?

Shallow breathing, pain, surfactant loss, airway obstruction, lung compression (fluid, tumor), fibrosis

Q35: What are the clinical signs of atelectasis?

Dyspnea, tachypnea, diminished breath sounds, asymmetrical chest movement, tracheal deviation

Q36: How is atelectasis prevented and treated?

• Prevention: Deep breathing, coughing, ambulation, pain control.

• Treatment: Incentive spirometry, CPAP, remove obstruction or fluid, antibiotics if infection