Q21. Which of the following best describes the function of the epiglottis in the respiratory system?
a) To regulate airflow in the bronchi
b) To produce mucus for air filtration
c) To facilitate gas exchange in the alveoli
d) To prevent food from entering the trachea during swallowing
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Correct Answer: d) To prevent food from entering the trachea during swallowing
Explanation: The epiglottis is a flap of tissue located at the entrance to the trachea. Its primary function is to close over the trachea during swallowing, preventing food and liquids from entering the airway and directing them toward the esophagus instead.
Q22. What role does the medulla oblongata play in the regulation of breathing?
a) It controls voluntary breathing movements.
b) It senses oxygen levels in the bloodstream.
c) It adjusts breathing rate and depth based on carbon dioxide levels.
d) It produces hormones that regulate respiration.
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Correct Answer: c) It adjusts breathing rate and depth based on carbon dioxide levels.
Explanation: The medulla oblongata contains respiratory centers that regulate the basic rhythm of breathing. It senses carbon dioxide levels in the bloodstream and adjusts breathing rate and depth accordingly to maintain homeostasis. This process is primarily involuntary and helps ensure adequate oxygen supply and removal of carbon dioxide.
Q23. Which of the following respiratory structures is responsible for the initial filtration of inhaled air?
a) Pharynx
b) Larynx
c) Nasal cavity
d) Trachea
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Correct Answer: c) Nasal cavity
Explanation: The nasal cavity contains mucous membranes and cilia that help filter out dust, pollen, and other particles from inhaled air. The mucous membranes produce mucus, which traps particles, while the cilia move the mucus and trapped particles toward the throat, where they can be swallowed or expelled.
Q24. 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.
Q25. Which of the following statements best describes the role of the bronchioles in the respiratory system?
a) They produce mucus for air filtration.
b) They facilitate gas exchange in the alveoli.
c) They regulate airflow in the bronchi.
d) They passageways for air to and from the lungs.
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Correct Answer: b) They facilitate gas exchange in the alveoli.
Explanation: Bronchioles are small, branching airways in the lungs that lead to the alveolar sacs. They help regulate airflow and control air distribution within the lungs. Bronchioles do not directly participate in gas exchange, but they lead to the alveoli where gas exchange occurs.
Q26. What is the primary function of the alveoli in the respiratory system?
a) To produce mucus for air filtration
b) To regulate airflow in the bronchi
c) To facilitate gas exchange
d) To warm and humidify inhaled air
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Correct Answer: c) To facilitate gas exchange
Explanation: Alveoli are small, air-filled sacs located at the ends of bronchioles in the lungs. They are the primary sites of gas exchange, where oxygen from inhaled air diffuses into the bloodstream and carbon dioxide from the bloodstream diffuses into the alveolar air for exhalation.
Q27. Which of the following respiratory structures is lined with ciliated cells and mucus-producing cells?
a) Bronchi
b) Alveoli
c) Larynx
d) Trachea
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Correct Answer: a) Bronchi
Explanation: The bronchi are the main airways that branch off from the trachea and extend into the lungs. They 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 for removal.
Q28. What is the role of the pleurae in the respiratory system?
a) To produce mucus for air filtration
b) To regulate airflow in the bronchi
c) To protect the lungs
d) To reduce friction during breathing
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Correct Answer: d) To reduce 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.
Q29. Which part of the brain is responsible for the involuntary control of breathing?
a) Cerebellum
b) Cerebrum
c) Medulla oblongata
d) Hypothalamus
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Correct Answer: c) Medulla oblongata
Explanation: The medulla oblongata, located in the brainstem, contains respiratory centers that regulate the basic rhythm of breathing. It receives input from chemoreceptors and other sensory receptors to adjust breathing rate and depth as needed to maintain homeostasis. This process is primarily involuntary.
Q30. What is the function of the epiglottis during swallowing?
a) To regulate airflow in the bronchi
b) To produce mucus for air filtration
c) To facilitate gas exchange in the alveoli
d) To prevent food from entering the trachea
Show Answer
Correct Answer: d) To prevent food from entering the trachea
Explanation: The epiglottis is a flap of tissue located at the entrance to the trachea. During swallowing, it closes over the trachea, preventing food and liquids from entering the airway and directing them toward the esophagus instead.