Asthma is difficulty in breathing with wheezing caused by inflammation of the bronchi and bronchioles (the air tubes get narrow). Emphysema is a long-term disorder where the alveolar walls are damaged, so the respiratory surface for gas exchange decreases; its main cause is cigarette smoking. Memory hook: Asthma = "Airways narrow" (tubes), Emphysema = "Empty sacs" (broken alveoli).
Asthma inflames and narrows the bronchi/bronchioles (tubes stay-alveoli intact, surface area unchanged), while emphysema destroys alveolar walls, decreasing the respiratory (gas-exchange) surface - the exact contrast NEET tests.
Your doubts, answered
In asthma, what exactly is inflamed?
The bronchi and bronchioles (the smaller air tubes) become inflamed and narrow. NCERT is exact here: asthma is difficulty in breathing causing wheezing due to inflammation of bronchi and bronchioles. It is NOT inflammation of the trachea, and it does not damage the alveoli. This narrowing of the tubes is what makes air whistle out (wheezing).
What is damaged in emphysema, and what is the result?
In emphysema the alveolar walls are damaged. Because alveoli are the gas-exchange surface, breaking their walls means the respiratory (exchange) surface decreases. Less surface means less oxygen enters the blood. Remember: emphysema attacks the alveoli, asthma attacks the air tubes.
Why is emphysema tied to smoking but asthma to allergens?
NCERT names cigarette smoking as one of the major causes of emphysema - smoke chemicals slowly destroy alveolar walls. Asthma, on the other hand, is triggered by allergens and pollutants that set off an allergic (mast cell) reaction, inflaming the bronchioles. So the cause words are different: emphysema = smoking, asthma = allergy/pollutants.
Does asthma decrease the respiratory surface area?
No. This is the trap. Asthma narrows the tubes (bronchi/bronchioles) but the alveoli stay intact, so the respiratory surface is not reduced. It is emphysema that decreases the respiratory surface by damaging alveolar walls. NEET 2018 asked exactly this contrast.
Is asthma reversible while emphysema is chronic?
For NEET the key line is: asthma is difficulty in breathing (an inflammatory, often episodic response to allergens), while emphysema is a chronic disorder with permanent structural damage to alveoli. Focus on the NCERT cause and site, since that is what questions test.
⚠️ The NEET trap ✗ Asthma damages the alveolar walls and decreases the respiratory surface. ✓ Asthma inflames the bronchi and bronchioles (tubes) - it is EMPHYSEMA that damages alveolar walls and decreases the respiratory surface. 🧠 Match the site: Asthma to bronchioles, Emphysema to alveoli. Swap them and you lose the mark (NEET 2018 did exactly this swap).
Real NEET questions
NEET 2018
Which of the following options correctly represents the lung conditions in asthma and emphysema, respectively?
A · Increased respiratory surface; Inflammation of bronchioles
B · Increased number of bronchioles; Increased respiratory surface
C · Inflammation of bronchioles; Decreased respiratory surface ✓
D · Decreased respiratory surface; Inflammation of bronchioles
Solution: Asthma = inflammation of bronchi and bronchioles. Emphysema = alveolar walls damaged, so respiratory surface is decreased. Matching in order (asthma, then emphysema) gives 'Inflammation of bronchioles; Decreased respiratory surface'. Option (D) reverses the pair, which is the common trap.
NEET 2016 Phase 1
Name the chronic respiratory disorder caused mainly by cigarette smoking:
A · Emphysema ✓
B · Asthma
C · Respiratory acidosis
D · Respiratory alkalosis
Solution: NCERT states emphysema is a chronic disorder in which alveolar walls are damaged, and names cigarette smoking as one of its major causes. Asthma is caused by inflammation of bronchi/bronchioles (allergens), while acidosis and alkalosis are pH disturbances, not smoking-induced chronic lung disorders.
NEET 2019
Due to increasing air-borne allergens and pollutants, many people in urban areas are suffering from respiratory disorder causing wheezing due to:
A · benign growth on mucous lining of nasal cavity
B · inflammation of bronchi and bronchioles ✓
C · proliferation of fibrous tissues and damage of the alveolar walls
D · reduction in the secretion of surfactants by pneumocytes
Solution: Wheezing triggered by allergens and pollutants is asthma, defined by NCERT as difficulty in breathing due to inflammation of bronchi and bronchioles. Option (C) describes alveolar wall damage (emphysema/fibrosis), not asthma.
Solved Breathing and Exchange of Gases NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
What is the one-line difference between asthma and emphysema?
Asthma = inflammation of the bronchi and bronchioles causing wheezing; emphysema = damage to alveolar walls that decreases the respiratory surface, caused mainly by smoking.
Which one is caused by smoking?
Emphysema. NCERT names cigarette smoking as one of its major causes. Asthma is triggered by allergens and pollutants.
Which disorder reduces gas-exchange surface area?
Emphysema, because it destroys alveolar walls. Asthma narrows the tubes but keeps the alveoli intact, so it does not reduce the surface area.
Is wheezing a sign of asthma or emphysema?
Wheezing is the classic sign of asthma, caused by narrowed, inflamed bronchi and bronchioles.
Which cells are involved in the allergic reaction of asthma?
Mast cells in the lungs release chemicals like histamine during the allergic reaction, inflaming the airways. This is why NEET 2016 gave 'allergic reaction of mast cells' as the cause of asthma.
