Q11. Which of the following respiratory structures is lined with cilia and mucus-producing cells to trap and remove particles from the air?
a) Alveoli
b) Bronchi
c) Pharynx
d) Larynx
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Correct Answer: b) Bronchi
Explanation: The bronchi are lined with ciliated epithelial cells and goblet cells that produce mucus. The cilia beat in coordinated waves to move mucus and trapped particles upward toward the throat, where they can be swallowed or expelled.
Q12. What is the role of hemoglobin in the respiratory system?
a) Transporting oxygen from the lungs to body tissues
b) Removing carbon dioxide from the bloodstream
c) Regulating the pH of blood
d) Facilitating gas exchange in the alveoli
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Correct Answer: a) Transporting oxygen from the lungs to body tissues
Explanation: Hemoglobin is a protein found in red blood cells that binds to oxygen molecules in the lungs and carries them through the bloodstream to tissues throughout the body. This allows oxygen to be delivered to cells for cellular respiration.
Q13. Which of the following structures is responsible for dividing the nasal cavity into left and right sides?
a) Nasal conchae
b) Nasal septum
c) Nasopharynx
d) Nasal vestibule
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Correct Answer: b) Nasal septum
Explanation: The nasal septum is a partition composed of bone and cartilage that divides the nasal cavity into left and right sides. It helps to support the structure of the nose and ensures that air flows evenly through both nasal passages.
Q14. What is the function of the alveolar sacs in the lungs?
a) Gas exchange
b) Production of mucus
c) Passage of air to and from the lungs
d) Protection of the lungs from infection
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Correct Answer: a) Gas exchange
Explanation: Alveolar sacs are clusters of alveoli, the primary sites of gas exchange in the lungs. Oxygen from inhaled air diffuses across the thin walls of the alveoli into the bloodstream, while carbon dioxide from the bloodstream diffuses into the alveoli to be exhaled.
Q15. What is the purpose of the mucociliary escalator in the respiratory system?
a) To warm and humidify inhaled air
b) To regulate airflow in the bronchi
c) To filter out particles and pathogens
d) To facilitate gas exchange in the alveoli
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Correct Answer: c) To filter out particles and pathogens
Explanation: The mucociliary escalator refers to the coordinated action of cilia and mucus in the respiratory tract to trap and remove inhaled particles, pathogens, and debris. Ciliated cells move the mucus and trapped particles upward toward the throat, where they can be expelled or swallowed.
Q16. Which of the following best describes the role of the respiratory system in maintaining homeostasis?
a) Regulation of blood pressure
b) Regulation of body temperature
c) Regulation of blood pH
d) Regulation of hormone levels
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Correct Answer: c) Regulation of blood pH
Explanation: The respiratory system plays a crucial role in regulating blood pH by controlling the levels of carbon dioxide in the bloodstream. Carbon dioxide reacts with water to form carbonic acid, which can alter blood pH. By adjusting breathing rate and depth, the respiratory system helps maintain the acid-base balance in the body.
Q17. What is the role of the pleurae in the respiratory system?
a) Production of mucus
b) Regulation of airflow
c) Protection of the lungs
d) Reduction of friction during breathing
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Correct Answer: d) Reduction of friction during breathing
Explanation: The pleurae are thin, double-layered membranes that surround each lung and line the thoracic cavity. They produce pleural fluid, which lubricates the surfaces of the lungs and chest wall, reducing friction during breathing and allowing the lungs to expand and contract smoothly.
Q18. Which of the following statements best describes the process of external respiration in the respiratory system?
a) Exchange of gases between the blood and body tissues
b) Exchange of gases between the blood and alveoli in the lungs
c) Exchange of gases between the atmosphere and alveoli
d) Exchange of gases between the atmosphere and body tissues
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Correct Answer: c) Exchange of gases between the atmosphere and alveoli
Explanation: External respiration refers to the exchange of gases (oxygen and carbon dioxide) between the alveoli in the lungs and the bloodstream. Oxygen from inhaled air diffuses into the bloodstream, while carbon dioxide from the bloodstream diffuses into the alveoli to be exhaled.
Q19. What is the primary function of the respiratory system in the human body?
a) Digestion
b) Circulation
c) Respiration
d) Excretion
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Correct Answer: c) Respiration
Explanation: The primary function of the respiratory system is respiration, which involves the exchange of gases (oxygen and carbon dioxide) between the body and the external environment. This process provides oxygen for cellular respiration, the metabolic process that produces energy, and removes carbon dioxide waste from the body.
Q20. Which of the following respiratory structures is responsible for generating sound in humans?
a) Bronchi
b) Alveoli
c) Larynx
d) Trachea
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Correct Answer: c) Larynx
Explanation: The larynx, also known as the voice box, contains vocal cords that vibrate as air passes over them, producing sound. The muscles of the larynx control the tension and position of the vocal cords to produce different pitches and volumes of sound.