Q41. What is the main function of the rib cage 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 facilitate gas exchange in the alveoli
Show Answer
Correct Answer: c) To protect the lungs
Explanation: The rib cage consists of bones (ribs and sternum) that surround and protect the lungs, heart, and other vital organs in the thoracic cavity. It provides structural support and helps prevent injury to the lungs from external forces.
Q42. What is the primary function of the respiratory system in the human body?
a) Digestion
b) Circulation
c) Respiration
d) Excretion
Show Answer
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.
Q43. Which of the following respiratory structures is responsible for generating sound in humans?
a) Bronchi
b) Alveoli
c) Larynx
d) Trachea
Show Answer
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.
Q44. 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
Show Answer
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.
Q45. Which of the following respiratory structures is lined with ciliated cells and mucus-producing cells?
a) Bronchi
b) Alveoli
c) Larynx
d) Trachea
Show Answer
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.
Q46. 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
Show Answer
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.
Q47. 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.
Show Answer
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.
Q48. 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
Show Answer
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.
Q49. 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
Show Answer
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.
Q50. Which part of the brain is responsible for the involuntary control of breathing?
a) Cerebellum
b) Cerebrum
c) Medulla oblongata
d) Hypothalamus
Show Answer
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.