NEET Biology: Respiratory system in humans Practice Questions
15 free multiple-choice questions on Respiratory system in humans (Human Physiology) for NEET Biology, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. Where does the flow of air change direction in the human respiratory system?
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Correct answer: A — Bronchus
Air flows from the trachea into the bronchi, which further divide into bronchioles, demonstrating a change in pathway direction as it moves deeper into the lungs.
Q2. Which muscle is primarily responsible for the active process of inhalation (inspiration)?
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Correct answer: B — Diaphragm
The diaphragm is the principal muscle of respiration. Its contraction pulls the rib cage down, increasing the volume of the thoracic cavity, which facilitates air inhalation.
Q3. Which structure acts as the passageway for air entering the lungs?
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Correct answer: C — Trachea
The trachea (windpipe) is the main tube that carries air from the larynx down to the bronchi, serving as the main airway to the lungs.
Q4. Which structure provides the largest surface area for the exchange of oxygen and carbon dioxide in the human respiratory system?
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Correct answer: D — Alveoli
The alveoli, tiny air sacs in the lungs, provide an extremely large surface area and thin walls, which are essential for the highly efficient diffusion of gases (oxygen and carbon dioxide) between the inhaled air and the blood.
Q5. Which type of tissue forms the walls of the bronchi and bronchioles?
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Correct answer: A — Pseudostratified ciliated columnar epithelium
The walls of the bronchi and bronchioles are lined with pseudostratified ciliated columnar epithelium, which helps in mucus transport.
Q6. What is the main function of the pleura surrounding the lungs?
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Correct answer: B — To facilitate friction-free movement of the lungs during breathing
The pleura forms a double-layered membrane that allows the lungs to expand and contract smoothly with each breath, minimizing friction during ventilation.
Q7. The pleura surrounds the lungs and provides a smooth, frictionless surface for breathing. What is the primary function of the pleura?
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Correct answer: B — To allow the lungs to expand and contract
The pleura membranes allow the lungs to expand and contract during the breathing process by reducing friction between the lung and the chest wall.
Q8. Which structure in the human respiratory system is the primary site for the exchange of oxygen and carbon dioxide between the air and the blood?
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Correct answer: C — Alveoli
The alveoli, tiny air sacs in the lungs, are the specialized structures where external respiration (gas exchange) occurs between the inhaled air and the pulmonary capillaries.
Q9. Which substance in the blood is primarily responsible for transporting oxygen from the lungs to the rest of the body?
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Correct answer: C — Hemoglobin
Hemoglobin, found in red blood cells, binds reversibly with oxygen and is the main carrier of oxygen in the blood.
Q10. Which muscle is the principal muscle involved in the process of breathing (ventilation)?
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Correct answer: C — Diaphragm
The diaphragm contracts and flattens during inhalation, increasing the volume of the thoracic cavity, which is the main driver of breathing.
Q11. What is the primary function of the respiratory system?
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Correct answer: A — To facilitate the exchange of gases between the body and the environment
The main purpose of the respiratory system is to take in oxygen and expel carbon dioxide, which is the fundamental process of gas exchange for sustaining life.
Q12. What is the primary substance that diffuses from the alveoli into the pulmonary capillaries during inhalation?
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Correct answer: D — Oxygen
Oxygen is the primary gas that moves from the high concentration in the alveoli into the blood capillaries due to the partial pressure difference.
Q13. In the path of air, the structure immediately following the bronchi is the:
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Correct answer: D — Bronchioles
The bronchi divide into progressively smaller tubes called bronchioles, which ultimately lead to the microscopic air sacs known as alveoli.
Q14. Which process involves the movement of air into the lungs due to the difference in pressure between the atmosphere and the lungs?
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Correct answer: A — Ventilation
Ventilation is the physical process of moving air into and out of the lungs, driven by pressure gradients (the difference in atmospheric pressure and intrapulmonary pressure).
Q15. Which structure is primarily responsible for the bulk of air movement into the lungs during inhalation?
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Correct answer: D — Diaphragm
The diaphragm is the most important muscle for breathing, as its contraction causes it to descend, increasing the volume of the thoracic cavity and facilitating inhalation.
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