MCQ 41:
Which gas is a byproduct of cellular respiration?
A) Oxygen
B) Nitrogen
C) Carbon dioxide
D) Hydrogen
Answer: C) Carbon dioxide
Explanation: Carbon dioxide is produced as a waste product during cellular respiration when cells metabolize glucose for energy.
MCQ 42:
What is the term for an increased breathing rate that can occur during exercise?
A) Bradypnea
B) Tachypnea
C) Hyperventilation
D) Hypoventilation
Answer: B) Tachypnea
Explanation: Tachypnea refers to an increased breathing rate, which often occurs during physical activity to meet the body’s increased oxygen demand.
MCQ 43:
The respiratory membrane is composed of:
A) Alveolar epithelium and capillary endothelium
B) Mucous membrane and ciliated epithelium
C) Ciliated epithelium and cartilage
D) Simple squamous epithelium and connective tissue
Answer: A) Alveolar epithelium and capillary endothelium
Explanation: The respiratory membrane consists of the alveolar epithelium and the endothelium of capillaries, facilitating gas exchange.
MCQ 44:
Which of the following is a symptom of a respiratory infection?
A) Joint pain
B) Skin rash
C) Coughing
D) Nausea
Answer: C) Coughing
Explanation: Coughing is a common symptom of respiratory infections, helping to clear mucus and pathogens from the airways.
MCQ 45:
The primary function of the intercostal muscles during respiration is to:
A) Control the diaphragm
B) Change the volume of the thoracic cavity
C) Facilitate gas exchange
D) Produce sound
Answer: B) Change the volume of the thoracic cavity
Explanation: The intercostal muscles contract to expand and elevate the ribcage, increasing the volume of the thoracic cavity during inhalation.
MCQ 46:
What is the effect of high altitude on oxygen availability?
A) Increased oxygen availability
B) No effect on oxygen availability
C) Decreased oxygen availability
D) Oxygen becomes toxic
Answer: C) Decreased oxygen availability
Explanation: At high altitudes, the partial pressure of oxygen is lower, resulting in decreased oxygen availability for respiration.
MCQ 47:
What mechanism allows for the movement of oxygen from the alveoli into the blood?
A) Active transport
B) Osmosis
C) Diffusion
D) Filtration
Answer: C) Diffusion
Explanation: Oxygen moves from the alveoli to the blood in the capillaries by diffusion, due to the concentration gradient.
MCQ 48:
Which type of cells produce surfactant in the alveoli?
A) Type I alveolar cells
B) Type II alveolar cells
C) Macrophages
D) Endothelial cells
Answer: B) Type II alveolar cells
Explanation: Type II alveolar cells are responsible for producing surfactant, which reduces surface tension and prevents alveolar collapse.
MCQ 49:
What is a common effect of bronchoconstriction?
A) Increased airflow
B) Decreased airflow
C) Increased lung volume
D) Decreased blood pressure
Answer: B) Decreased airflow
Explanation: Bronchoconstriction narrows the airways, leading to decreased airflow to and from the lungs.
MCQ 50:
Which part of the respiratory system is involved in both respiration and digestion?
A) Larynx
B) Pharynx
C) Trachea
D) Bronchi
Answer: B) Pharynx
Explanation: The pharynx is a shared passageway for both air (respiration) and food (digestion).
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