MCQ 71:
What type of cells are responsible for the immune response in the alveoli?
A) Type I alveolar cells
B) Type II alveolar cells
C) Alveolar macrophages
D) Endothelial cells
Answer: C) Alveolar macrophages
Explanation: Alveolar macrophages are immune cells that reside in the alveoli and help to engulf and destroy pathogens.
MCQ 72:
The lungs are surrounded by a double-layered membrane known as:
A) Mucosa
B) Serosa
C) Pleura
D) Peritoneum
Answer: C) Pleura
Explanation: The pleura is a double-layered membrane that surrounds the lungs and lines the thoracic cavity, providing a lubricated surface for lung movement.
MCQ 73:
Which lung capacity includes tidal volume and the inspiratory reserve volume?
A) Vital capacity
B) Functional residual capacity
C) Total lung capacity
D) Inspiratory capacity
Answer: D) Inspiratory capacity
Explanation: Inspiratory capacity is the sum of tidal volume and inspiratory reserve volume, representing the maximum amount of air that can be inhaled after a normal expiration.
MCQ 74:
What role do the respiratory and circulatory systems play in maintaining homeostasis?
A) They regulate blood glucose levels.
B) They maintain acid-base balance through gas exchange.
C) They control body temperature.
D) They detoxify the blood.
Answer: B) They maintain acid-base balance through gas exchange.
Explanation: The respiratory and circulatory systems work together to regulate pH levels in the blood by controlling the levels of carbon dioxide and oxygen.
MCQ 75:
What is the main factor that drives oxygen from the lungs into the blood?
A) Temperature
B) Partial pressure gradient
C) Humidity
D) Blood flow rate
Answer: B) Partial pressure gradient
Explanation: The movement of oxygen from the lungs into the blood occurs due to the partial pressure gradient, with oxygen moving from an area of higher pressure (lungs) to lower pressure (blood).
MCQ 76:
What is the main physiological effect of hypoxia?
A) Increased respiratory rate
B) Decreased respiratory rate
C) Decreased heart rate
D) Increased blood pressure
Answer: A) Increased respiratory rate
Explanation: Hypoxia, or low oxygen levels in the tissues, triggers an increase in respiratory rate to enhance oxygen intake.
MCQ 77:
Which of the following terms describes the volume of air that can be forcibly exhaled after a normal expiration?
A) Tidal volume
B) Expiratory reserve volume
C) Inspiratory reserve volume
D) Vital capacity
Answer: B) Expiratory reserve volume
Explanation: Expiratory reserve volume is the amount of air that can be forcibly exhaled after a normal tidal expiration.
MCQ 78:
The law that states that the total pressure of a gas mixture is equal to the sum of the partial pressures of its components is known as:
A) Boyle’s law
B) Dalton’s law
C) Henry’s law
D) Charles’s law
Answer: B) Dalton’s law
Explanation: Dalton’s law states that the total pressure of a gas mixture is the sum of the partial pressures of each individual gas in the mixture.
MCQ 79:
Which of the following best describes the “sneeze reflex”?
A) A protective mechanism to expel air quickly to clear irritants
B) A mechanism to increase oxygen intake
C) A process of gas exchange
D) A method of regulating blood pH
Answer: A) A protective mechanism to expel air quickly to clear irritants
Explanation: The sneeze reflex is a protective action that expels air rapidly from the lungs to remove irritants from the nasal cavity.
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