Respiratory System MCQs for NEET UG

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Respiratory System MCQs for NEET UG

Q1. Which structure prevents food entry into the larynx?

a) Glottis

b) Epiglottis

c) Uvula

d) Vocal cords

Answer: b) Epiglottis

Explanation: The epiglottis is a leaf-shaped flap that covers the larynx during swallowing (NEET 2022).


Q2. Oxygen dissociation curve shifts right in:

a) High pH

b) Low temperature

c) High pCO₂

d) Low 2,3-DPG

Answer: c) High pCO₂

Explanation: Bohr effect - Increased CO₂ decreases Hb's O₂ affinity (NEET 2021).


Q3. CO₂ is primarily transported as:

a) Carbaminohemoglobin

b) Bicarbonate

c) Dissolved gas

d) Carbonate

Answer: b) Bicarbonate

Explanation: 70% as HCO₃⁻ via carbonic anhydrase in RBCs (NEET 2020).


Q4. Chloride shift occurs in:

a) Pulmonary capillaries

b) Tissue capillaries

c) Alveoli

d) Bronchioles

Answer: b) Tissue capillaries

Explanation: Cl⁻ moves into RBCs to maintain electroneutrality when HCO₃⁻ diffuses out (NEET 2019).


Q5. "Barrel chest" is seen in:

a) Asthma

b) Emphysema

c) Tuberculosis

d) Pneumonia

Answer: b) Emphysema

Explanation: Increased AP diameter due to air trapping (NEET 2021).


Q6. Kussmaul breathing indicates:

a) Metabolic acidosis

b) Respiratory alkalosis

c) Hypoxia

d) Hypercapnia

Answer: a) Metabolic acidosis

Explanation: Deep, rapid breathing to compensate for acidemia (e.g., DKA) (NEET 2023).


Q7. Spirometry in COPD shows:

a) ↑ FEV₁/FVC

b) ↓ FEV₁/FVC

c) Normal FVC

d) ↑ TLC

Answer: b) ↓ FEV₁/FVC

Explanation: Obstructive pattern (FEV₁/FVC <70%) (NEET 2020).


Q8. Surfactant is secreted by:

a) Type I pneumocytes

b) Type II pneumocytes

c) Macrophages

d) Goblet cells

Answer: b) Type II pneumocytes

Explanation: Reduces alveolar surface tension (NEET 2018).


Q9. Majority of oxygen in blood is transported as:

a) Dissolved in plasma

b) Oxyhemoglobin

c) Carbaminohemoglobin

d) Bicarbonate

Answer: b) Oxyhemoglobin

Explanation: 97% of O₂ binds to hemoglobin (Fe²⁺ in heme), forming oxyhemoglobin (NEET 2021).


Q10. Chloride shift maintains:

a) Blood pH

b) Electrical neutrality

c) Oxygen affinity

d) Alveolar pressure

Answer: b) Electrical neutrality

Explanation: Cl⁻ moves into RBCs to balance HCO₃⁻ outflow during CO₂ transport (NEET 2019).


Q11. The primary respiratory center is located in:

a) Cerebrum

b) Medulla oblongata

c) Cerebellum

d) Hypothalamus

Answer: b) Medulla oblongata

Explanation: Dorsal respiratory group in medulla sets basic rhythm (NEET 2022).


Q12. Peripheral chemoreceptors respond to:

a) ↑ pO₂

b) ↓ pO₂ (<60 mmHg)

c) ↑ pH

d) ↓ pCO₂

Answer: b) ↓ pO₂ (<60 mmHg)

Explanation: Carotid/aortic bodies detect hypoxemia (NEET 2020).


Q13. "Pink puffer" is a characteristic of:

a) Chronic bronchitis

b) Emphysema

c) Asthma

d) Pneumonia

Answer: b) Emphysema

Explanation: Patients maintain oxygenation (pink) but have dyspnea (puffing) due to destroyed alveoli (NEET 2021).


Q14. Blue bloater" describes:

a) Emphysema

b) Chronic bronchitis

c) ARDS

d) Tuberculosis

Answer: b) Chronic bronchitis

Explanation: Cyanosis (blue) and edema (bloater) from hypoxemia and cor pulmonale (NEET 2018).


Q15. PaO₂ <60 mmHg with PaCO₂ >50 mmHg indicates:

a) Type I respiratory failure

b) Type II respiratory failure

c) Metabolic acidosis

d) Respiratory alkalosis

Answer: b) Type II respiratory failure

Explanation: Hypoxemia with hypercapnia (e.g., COPD exacerbation) (NEET 2023).


Q16. FEV₁/FVC ratio in restrictive lung disease is:

a) <70%

b) >80%

c) Normal

d) Variable

Answer: b) >80%

Explanation: Both FEV₁ and FVC decrease proportionally (e.g., pulmonary fibrosis) (NEET 2020).


Q17. Non-invasive ventilation (BiPAP) is contraindicated in:

a) COPD exacerbation

b) Cardiogenic pulmonary edema

c) Undrained pneumothorax

d) Obesity hypoventilation

Answer: c) Undrained pneumothorax

Explanation: Positive pressure can worsen air leak (NEET 2021).


Q18. Theophylline acts by inhibiting:

a) β₂ receptors

b) Phosphodiesterase

c) Acetylcholinesterase

d) Histamine receptors

Answer: b) Phosphodiesterase

Explanation: Increases cAMP → bronchodilation (NEET 2019).


Q19. Haldane effect describes:

a) CO₂'s influence on Hb-O₂ affinity

b) O₂'s influence on Hb-CO₂ binding

c) Chloride shift mechanism

d) Surfactant function

Answer: b) O₂'s influence on Hb-CO₂ binding

Explanation: Deoxygenated Hb binds CO₂ more readily than oxygenated Hb (NEET 2021).


Q20. At high altitudes, the body compensates by:

a) Decreasing 2,3-DPG

b) Increasing ventilation

c) Reducing erythropoietin

d) Constricting pulmonary vessels

Answer: b) Increasing ventilation

Explanation: Hypoxia stimulates peripheral chemoreceptors → hyperventilation (NEET 2022).


Q21. "Eggshell calcifications" on CXR are pathognomonic for:

a) Silicosis

b) Tuberculosis

c) Asbestosis

d) Sarcoidosis

Answer: a) Silicosis

Explanation: Characteristic finding in silicosis (NEET 2020).


Q22. A patient with rust-colored sputum likely has:

a) Viral pneumonia

b) Tuberculosis

c) Pneumococcal pneumonia

d) Asthma

Answer: c) Pneumococcal pneumonia

Explanation: Rust-colored sputum suggests Streptococcus pneumoniae infection (NEET 2019).


Q23. Montelukast acts by blocking:

a) Histamine receptors

b) Leukotriene receptors

c) Muscarinic receptors

d) β₂-adrenergic receptors

Answer: b) Leukotriene receptors

Explanation: Leukotriene receptor antagonist used in asthma (NEET 2021).


Q24. Ipratropium bromide is contraindicated in:

a) COPD

b) Asthma

c) Peanut allergy

d) Hypertension

Answer: c) Peanut allergy

Explanation: Contains soy lecithin - risk of anaphylaxis in peanut-allergic patients (NEET 2023).


Q25. A premature neonate with grunting respirations and retractions likely has:

a) Croup

b) Respiratory Distress Syndrome

c) Bronchiolitis

d) Pneumothorax

Answer: b) Respiratory Distress Syndrome

Explanation: Due to surfactant deficiency (NEET 2022).


Q26. Cheyne-Stokes breathing is characteristically seen in:

a) Diabetic ketoacidosis

b) Heart failure

c) Asthma

d) Pulmonary embolism

Answer: b) Heart failure

Explanation: Cyclic breathing pattern due to delayed circulation time (NEET 2020).


Q27. Chest X-ray showing bilateral hilar lymphadenopathy].

a) Tuberculosis

b) Sarcoidosis

c) Lung cancer

d) Pneumonia

Answer: b) Sarcoidosis

Explanation: Bilateral hilar lymphadenopathy is classic for sarcoidosis (NEET 2021).


Q28. Spirometry showing reduced FVC with normal FEV₁/FVC ratio, This indicates

a) COPD

b) Asthma

c) Pulmonary fibrosis

d) Bronchiectasis

Answer: c) Pulmonary fibrosis

Explanation: Restrictive pattern (NEET 2019).


Q29. ARDS is characterized by:

a) High compliance

b) Diffuse alveolar damage

c) Pulmonary hypertension

d) Both b and c

Answer: d) Both b and c

Explanation: Diffuse alveolar damage leads to reduced compliance and pulmonary HTN (NEET 2023).


Q30. P/F ratio in ARDS is:

a) PaO₂/FiO₂ <300

b) PaCO₂/FiO₂ >200

c) SpO₂/FiO₂ <400

d) A-a gradient >50

Answer: a) PaO₂/FiO₂ <300

Explanation: Key diagnostic criterion (NEET 2021).

Q31. Maximum volume of air that can be inspired after normal tidal inspiration is called:

a) Inspiratory reserve volume

b) Expiratory reserve volume

c) Residual volume

d) Vital capacity

Answer: a) Inspiratory reserve volume

Explanation: IRV is the additional air that can be forcibly inhaled after normal inspiration (typically 2500-3000 mL).


Q32. Which of the following is NOT part of the respiratory membrane?

a) Alveolar epithelium

b) Capillary endothelium

c) Type II pneumocytes

d) Fused basement membranes

Answer: c) Type II pneumocytes

Explanation: The respiratory membrane consists of alveolar epithelium, capillary endothelium and their fused basement membranes - Type II cells produce surfactant but aren't part of the membrane.


Q33. A coal miner presenting with black sputum most likely has:

a) Silicosis

b) Anthracosis

c) Asbestosis

d) Byssinosis

Answer: b) Anthracosis

Explanation: Anthracosis is caused by coal dust deposition, leading to black pigmentation of lungs and sputum.


Q34. Which condition shows "coin lesion" on chest X-ray?

a) Tuberculosis

b) Bronchogenic carcinoma

c) Pulmonary edema

d) Pleural effusion

Answer: b) Bronchogenic carcinoma

Explanation: A well-circumscribed round lesion ("coin lesion") is characteristic of early lung cancer.


Q35. A patient with tracheal deviation to the left likely has:

a) Right pneumothorax

b) Left pleural effusion

c) Right lung collapse

d) Left lung consolidation

Answer: a) Right pneumothorax

Explanation: Trachea deviates away from tension pneumothorax due to increased pressure.


Q36.Which drug is contraindicated in acute asthma attack?

a) Salbutamol

b) Ipratropium

c) Propranolol

d) Theophylline

Answer: c) Propranolol

Explanation: Non-selective β-blockers can worsen bronchospasm in asthma.


Q37. "sail sign" on chest X-ray in children indicates:

a) Pneumonia

b) Thymus

c) Pneumothorax

d) Pleural effusion

Answer: b) Thymus

Explanation: The normal thymus appears as a triangular sail-shaped shadow in pediatric chest X-rays.


Q38. DLCO (Diffusing Capacity) is reduced in:

a) Emphysema

b) Asthma

c) Chronic bronchitis

d) Pulmonary hypertension

Answer: a) Emphysema

Explanation: Destruction of alveolar membranes reduces gas diffusion capacity.


Q39. COVID-19 primarily affects which part of respiratory system?

a) Type I pneumocytes

b) Type II pneumocytes

c) Bronchial epithelium

d) Nasal mucosa

Answer: a) Type I pneumocytes

Explanation: SARS-CoV-2 binds to ACE2 receptors abundant on Type I alveolar cells.


Q40. Ground glass opacities on HRCT are characteristic of:

a) COVID-19 pneumonia

b) Tuberculosis

c) Bronchiectasis

d) Pulmonary embolism

Answer: a) COVID-19 pneumonia

Explanation: GGO represents partial filling of airspaces, typical in viral pneumonias.


Q41.Primary stimulus for central chemoreceptors is:

a) Decreased arterial pO₂

b) Increased arterial pCO₂

c) Decreased blood pH

d) Increased 2,3-DPG levels

Answer: b) Increased arterial pCO₂

Explanation: Central chemoreceptors in the medulla respond to CO₂ changes via H⁺ ions in CSF (NEET 2022).


Q42. During exercise, oxygen dissociation curve shifts right due to:

a) Increased temperature and 2,3-DPG

b) Decreased pCO₂

c) Increased pH

d) Decreased temperature

Answer: a) Increased temperature and 2,3-DPG

Explanation: Exercise generates heat and 2,3-DPG, reducing Hb's O₂ affinity (Bohr effect).


Q43. "Westermark sign" on CXR is seen in:

a) Pulmonary embolism

b) Tuberculosis

c) Bronchogenic carcinoma

d) Pneumothorax

Answer: a) Pulmonary embolism

Explanation: Oligemia distal to pulmonary artery obstruction (NEET 2021).


Q44. "Cotton wool spots" in respiratory pathology suggest:

a) Silicosis

b) Asbestosis

c) Coal worker's pneumoconiosis

d) Byssinosis

Answer: c) Coal worker's pneumoconiosis

Explanation: Macrophage aggregates appear as fluffy opacities on X-ray.


Q45. A patient with tracheal tugging (Campbell's sign) likely has:

a) COPD

b) Large pleural effusion

c) Tension pneumothorax

d) Mediastinal mass

Answer: a) COPD

Explanation: Due to hyperinflation causing diaphragmatic flattening (NEET 2020).


Q46. "Hamman's crunch" on auscultation indicates:

a) Pneumonia

b) Mediastinal emphysema

c) Pleural rub

d) Pulmonary edema

Answer: b) Mediastinal emphysema

Explanation: Crunching sound heard in pneumomediastinum.


Q47. Biologic therapy is used in severe asthma targeting:

a) IL-5

b) Histamine

c) Acetylcholine

d) Prostaglandins

Answer: a) IL-5

Explanation: Mepolizumab (anti-IL5) for eosinophilic asthma (NEET 2023).


Q48. "Honeycomb lung" on HRCT is characteristic of:

a) Idiopathic pulmonary fibrosis

b) Sarcoidosis

c) Silicosis

d) Asbestosis

Answer: a) Idiopathic pulmonary fibrosis

Explanation: End-stage fibrotic changes with cystic spaces.


Q49. Oxygen-hemoglobin dissociation curve shifts left in:

a) High altitude

b) Fever

c) Fetal blood

d) Exercise

Answer: c) Fetal blood

Explanation: Fetal hemoglobin (HbF) has higher O₂ affinity due to reduced 2,3-DPG binding, causing a left shift (NEET 2023).


Q50. Primary muscle of forced expiration is:

a) Diaphragm

b) External intercostals

c) Internal intercostals

d) Rectus abdominis

Answer: d) Rectus abdominis

Explanation: Abdominal muscles contract during forced expiration to increase intra-abdominal pressure (NEET 2021).



Q51. "Honeycomb lung" on HRCT is pathognomonic for:

a) Sarcoidosis

b) Idiopathic pulmonary fibrosis

c) Silicosis

d) Tuberculosis

Answer: b) Idiopathic pulmonary fibrosis

Explanation: End-stage lung fibrosis with cystic spaces resembling a honeycomb (NEET 2022).


Q52. A patient with "egg-shell calcification" of hilar lymph nodes likely has:

a) Tuberculosis

b) Silicosis

c) Histoplasmosis

d) Sarcoidosis

Answer: b) Silicosis

Explanation: Thin, calcified rims around hilar nodes are characteristic of silicosis (NEET 2020).



Q53. A premature neonate with tachypnea and grunting likely has:

a) Croup

b) Respiratory distress syndrome

c) Bronchiolitis

d) Pneumonia

Answer: b) Respiratory distress syndrome

Explanation: Due to surfactant deficiency in preterm infants (NEET 2023).


Q54. "Pink puffer" vs "Blue bloater" distinguishes:

a) Asthma vs COPD

b) Emphysema vs chronic bronchitis

c) Pneumonia vs tuberculosis

d) Pulmonary edema vs fibrosis

Answer: b) Emphysema vs chronic bronchitis

Explanation: Pink puffers (emphysema) maintain oxygenation; blue bloaters (chronic bronchitis) develop hypoxemia and edema (NEET 2021).


Q55. Montelukast acts by blocking:

a) Histamine receptors

b) Leukotriene receptors

c) Muscarinic receptors

d) β₂-adrenergic receptors

Answer: b) Leukotriene receptors

Explanation: It inhibits cysteinyl leukotrienes (CysLT1) in asthma (NEET 2022).


Q56. Roflumilast is used in severe COPD to:

a) Reduce exacerbations

b) Relieve acute bronchospasm

c) Replace steroids

d) Treat infections

Answer: a) Reduce exacerbations

Explanation: PDE4 inhibitor decreases inflammation in chronic COPD (NEET 2023).


Q56. "Westermark sign" on CXR indicates:

a) Pulmonary embolism

b) Pneumothorax

c) Pleural effusion

d) Lung collapse

Answer: a) Pulmonary embolism

Explanation: Oligemia distal to a pulmonary artery obstruction (NEET 2021).


Q57. DLCO (Diffusing Capacity) is reduced in:

a) Asthma

b) Emphysema

c) Chronic bronchitis

d) Pulmonary hypertension

Answer: b) Emphysema

Explanation: Alveolar membrane destruction impairs gas diffusion (NEET 2020).




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