Title: Respiratory System – Notes, Functions, Disorders & 40+ MCQs for NEET/Class 11

 Introduction to the Respiratory System

The respiratory system is a vital network of organs and tissues that enables breathing. It plays a crucial role in supplying oxygen to the body’s cells and removing waste gases such as carbon dioxide. This continuous exchange helps in cellular respiration and maintains internal balance.

Parts of the Respiratory System

1. Nose and Nasal Cavity

• Air enters through the nose where nasal hairs filter out dust and pathogens.

• The nasal cavity warms and humidifies the air.

• Mucous membranes and cilia trap harmful particles.

2. Pharynx and Larynx

• Pharynx (throat): A shared passage for food and air.

• Larynx (voice box): Produces sound and directs air into the trachea, while preventing food entry into the airway.

3. Trachea (Windpipe)

• A cartilaginous tube connecting the larynx to the bronchi.

• Lined with cilia and mucus to trap and expel foreign particles.

4. Bronchi and Bronchioles

• Trachea divides into left and right bronchi, leading to each lung.

• Bronchi branch into smaller bronchioles that distribute air within the lungs.

5. Lungs and Alveoli

• The lungs house millions of alveoli – tiny air sacs.

• Gas exchange occurs here: oxygen enters the blood, and carbon dioxide exits.

6. Diaphragm and Intercostal Muscles

• Diaphragm: A dome-shaped muscle that contracts for inhalation and relaxes for exhalation.

• Intercostal muscles: Located between ribs; assist in expanding and contracting the chest cavity.

 Functions of the Respiratory System

• Gas Exchange: Supplies oxygen and removes carbon dioxide.

• Air Filtration: Filters dust and pathogens using nasal hairs and mucus.

• Sound Production: Larynx contains vocal cords for speech.

• Olfaction (Smell): Olfactory receptors detect airborne molecules.

• pH Regulation: Maintains blood pH by controlling CO₂ levels.

 Gas Exchange Process

• Inhaled oxygen reaches the alveoli.

• Oxygen diffuses into capillaries and binds with hemoglobin in red blood cells.

• Carbon dioxide from the blood diffuses into the alveoli and is exhaled.

 Common Respiratory Disorders

• Asthma: Inflammation and narrowing of airways.

• COPD (Chronic Obstructive Pulmonary Disease): Includes emphysema and chronic bronchitis.

• Pneumonia: An Infection causing fluid accumulation in the alveoli.

• Tuberculosis (TB): A Bacterial infection that damages lung tissue.

1. Which part of the respiratory system is primarily responsible for gas exchange?
   A) Trachea
   B) Bronchi
   C) Alveoli
   D) Larynx
   Answer: C) Alveoli

2. What is the primary muscle involved in the process of inhalation?
   A) Intercostal muscles
   B) Diaphragm
   C) Abdominal muscles
   D) Pectoral muscles
   Answer: B) Diaphragm

3. Which structure prevents food from entering the trachea during swallowing?
   A) Uvula
   B) Epiglottis
   C) Soft palate
   D) Larynx
   Answer: B) Epiglottis

4. The voice box is also known as the:
   A) Pharynx
   B) Larynx
   C) Trachea
   D) Bronchus
   Answer: B) Larynx

5. Which of the following is NOT a function of the respiratory system?
   A) Oxygen supply
   B) Carbon dioxide removal
   C) Regulation of blood pH
   D) Production of red blood cells
   Answer: D) Production of red blood cells

6. The trachea divides into two branches called:
   A) Bronchioles
   B) Alveoli
   C) Bronchi
   D) Larynx
   Answer: C) Bronchi

7. Which gas is primarily transported by hemoglobin in the blood?
   A) Carbon dioxide
   B) Nitrogen
   C) Oxygen
   D) Hydrogen
   Answer: C) Oxygen

8. What is the term for the tiny air sacs in the lungs where gas exchange occurs?
   A) Bronchi
   B) Alveoli
   C) Bronchioles
   D) Capillaries
   Answer: B) Alveoli

9. Which part of the brain regulates the rate and depth of breathing?
   A) Cerebrum
   B) Cerebellum
   C) Medulla oblongata
   D) Thalamus
   Answer: C) Medulla oblongata

10. The process of moving air into and out of the lungs is called:
    A) Respiration
    B) Ventilation
    C) Diffusion
    D) Circulation
    Answer: B) Ventilation

11. Which of the following structures is part of the upper respiratory tract?
    A) Trachea
    B) Larynx
    C) Pharynx
    D) Bronchi
    Answer: C) Pharynx

12. The exchange of gases between the blood and body tissues is known as:
    A) External respiration
    B) Internal respiration
    C) Cellular respiration
    D) Pulmonary ventilation
    Answer: B) Internal respiration

13. Which of the following is a respiratory pigment in humans?
    A) Hemoglobin
    B) Myoglobin
    C) Chlorophyll
    D) Melanin
    Answer: A) Hemoglobin

14. What is the main function of the cilia in the respiratory tract?
    A) Gas exchange
    B) Produce mucus
    C) Trap and move particles out of the airways
    D) Absorb oxygen
    Answer: C) Trap and move particles out of the airways

15. Which of the following is a common respiratory disorder characterized by airway inflammation and constriction?
    A) Asthma
    B) Diabetes
    C) Hypertension
    D) Arthritis
    Answer: A) Asthma

16. The diaphragm contracts during:
    A) Exhalation
    B) Inhalation
    C) Both inhalation and exhalation
    D) Neither inhalation nor exhalation
    Answer: B) Inhalation

17. Which structure connects the larynx to the bronchi?
    A) Pharynx
    B) Trachea
    C) Alveoli
    D) Nasal cavity
    Answer: B) Trachea

18. The amount of air inhaled or exhaled during normal breathing is called:
    A) Tidal volume
    B) Residual volume
    C) Vital capacity
    D) Total lung capacity
    Answer: A) Tidal volume

19. Which of the following is NOT a component of the respiratory system?
    A) Nose
    B) Lungs
    C) Esophagus
    D) Trachea
    Answer: C) Esophagus

20. The pleura is a:
    A) Muscle involved in breathing
    B) Cartilage in the trachea
    C) Membrane surrounding the lungs
    D) Part of the larynx
    Answer: C) Membrane surrounding the lungs

21. Which gas is the primary driver for the urge to breathe?
    A) Oxygen
    B) Carbon dioxide
    C) Nitrogen
    D) Hydrogen
    Answer: B) Carbon dioxide

22. The smallest air passages in the lungs are called:
    A) Bronchi
    B) Bronchioles
    C) Alveoli
    D) Trachea
    Answer: B) Bronchioles

23. Which of the following is a function of the nasal cavity?
    A) Gas exchange
    B) Filtering, warming, and humidifying air
    C) Producing red blood cells
    D) Digesting food
    Answer: B) Filtering, warming, and humidifying air

24. During exhalation, the diaphragm:
    A) Contracts and moves downward
    B) Relaxes and moves upward
    C) Contracts and moves upward
    D) Relaxes and moves downward
    Answer: B) Relaxes and moves upward

25. Which of the following structures is shared by both the respiratory and digestive systems?
    A) Larynx
    B) Pharynx
    C) Trachea
    D) Esophagus
    Answer: B) Pharynx

26. The process by which oxygen and carbon dioxide are exchanged in the lungs is called:
    A) Internal respiration
    B) External respiration
    C) Cellular respiration
    D) Ventilation
    Answer: B) External respiration

27. Which of the following is a chronic obstructive pulmonary disease (COPD)?
    A) Asthma
    B) Emphysema
    C) Tuberculosis
    D) Pneumonia
    Answer: B) Emphysema

28. The main passageway for air into the respiratory system is the:
    A) Mouth
    B) Nose
    C) Pharynx
    D) Larynx
    Answer: B) Nose

29. Which part of the respiratory system is responsible for sound production?
    A) Pharynx
    B) Larynx
    C) Trachea
    D) Bronchi
    Answer: B) Larynx

30. The exchange of gases between the alveoli and the blood occurs by:
    A) Active transport
    B) Osmosis
    C) Diffusion
    D) Filtration
    Answer: C) Diffusion

31. Which of the following is NOT a symptom of respiratory distress?
    A) Shortness of breath
    B) Cyanosis
    C) Bradycardia
    D) Rapid breathing
    Answer: C) Bradycardia

32. The space between the lungs that contains the heart is called the:
    A) Pleural cavity
    B) Mediastinum
    C) Thoracic cavity
    D) Pericardial cavity
    Answer: B) Mediastinum

33. Which of the following diseases is caused by a bacterial infection affecting the lungs?
    A) Asthma
    B) Emphysema
    C) Tuberculosis
    D) Bronchitis
    Answer: C) Tuberculosis

34. The respiratory center that controls the rhythm of breathing is located in the:
    A) Cerebrum
    B) Cerebellum
    C) Medulla oblongata
    D) Hypothalamus
    Answer: C) Medulla oblongata

35. Which of the following is a function of the respiratory system?
    A) Production of digestive enzymes
    B) Regulation of body temperature
    C) Removal of metabolic waste
    D) Regulation of blood pH
    Answer: D) Regulation of blood pH

36. Which structure is responsible for closing off the nasal passages during swallowing?
    A) Uvula
    B) Epiglottis
    C) Soft palate
    D) Larynx
    Answer: C) Soft palate

37. The term ‘hypoxia’ refers to:
    A) Excess oxygen in the tissues
    B) Deficiency of oxygen in the tissues
    C) Excess carbon dioxide in the blood
    D) Deficiency of carbon dioxide in the blood
    Answer: B) Deficiency of oxygen in the tissues

38. Which of the following is a common symptom of bronchitis?
    A) Chest pain
    B) Persistent cough
    C) High fever
    D) Shortness of breath
    Answer: B) Persistent cough

39. The amount of air that remains in the lungs after a forceful exhalation is called:
    A) Tidal volume
    B) Residual volume
    C) Vital capacity
    D) Inspiratory reserve volume
    Answer: B) Residual volume

40. Which of the following is NOT a component of the lower respiratory tract?
    A) Trachea
    B) Bronchi
    C) Alveoli
    D) Pharynx
    Answer: D) Pharynx

Digestive System MCQ for NEET and Class 11

Cell and Its Structure Class 11 Biology MCQs with Answers

 The Human Eye

Visit Our Channel