Breathing and Exchange of Gases Chapter-Wise Test 10

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which of the following statements about alveolar gas exchange is correct?

Gas exchange occurs through active transport.
Oxygen diffuses from the blood into the alveoli.
The diffusion of gases occurs due to partial pressure gradients.
Carbon dioxide moves into the blood from the alveoli.
3

Gas exchange occurs passively through diffusion, driven by partial pressure gradients of oxygen and carbon dioxide.

Which of the following statements about carbon dioxide transport is incorrect?

Most CO₂ is transported as bicarbonate ions.
CO₂ binds to hemoglobin to form carbamino-hemoglobin.
CO₂ transport does not affect blood pH.
Carbonic anhydrase facilitates CO₂ conversion into bicarbonate.
3

CO₂ transport significantly affects blood pH by forming carbonic acid, which dissociates into bicarbonate and hydrogen ions.

Which of the following statements about the diaphragm is incorrect?

It contracts and moves downward during inspiration.
It relaxes and moves upward during expiration.
It is a skeletal muscle that plays a role in breathing.
It remains stationary during the breathing cycle.
4

The diaphragm moves actively during the breathing cycle, contracting during inspiration and relaxing during expiration.

Which center in the brainstem regulates the basic rhythm of respiration?

Cerebellum
Pneumotaxic center
Respiratory rhythm center in the medulla
Hypothalamus
3

The respiratory rhythm center in the medulla oblongata regulates the basic rhythm of breathing.

Which of the following best describes the function of the pneumotaxic center?

Initiates voluntary breathing
Moderates the respiratory rhythm center
Controls the diffusion of gases
Regulates oxygen transport
2

The pneumotaxic center in the pons moderates the function of the respiratory rhythm center by adjusting the duration of inspiration.

Which of the following factors increases the oxygen-binding affinity of hemoglobin?

Increase in pCO₂
Increase in H⁺ concentration
Decrease in temperature
Both 2 and 3
3

A decrease in temperature increases the oxygen-binding affinity of hemoglobin, promoting oxygen uptake in the lungs.

Which disorder is caused by long-term exposure to dust and results in fibrosis of lung tissues?

Emphysema
Asthma
Silicosis
Pneumonia
3

Silicosis is an occupational respiratory disorder caused by prolonged exposure to silica dust, leading to lung fibrosis.

Which of the following statements regarding oxygen transport is correct?

Oxygen is mainly transported in dissolved form in plasma.
Hemoglobin binds to oxygen reversibly.
All oxygen in the blood is transported by red blood cells.
Oxygen transport is not affected by temperature or pH changes.
2

Oxygen binds reversibly with hemoglobin, allowing efficient transport and release in tissues as needed.

Which of the following statements about breathing rate is incorrect?

Breathing rate is controlled by the medulla oblongata.
Increased CO₂ levels stimulate increased breathing rate.
Breathing rate is unaffected by oxygen levels in the blood.
Chemoreceptors help regulate breathing rate.
3

Oxygen levels do influence breathing rate, especially in cases of severe hypoxia.

Which of the following is NOT a factor affecting the rate of diffusion of gases in the lungs?

Partial pressure gradient
Membrane thickness
Solubility of gases
Heart rate
4

Heart rate does not directly affect the rate of gas diffusion in the lungs. Factors such as partial pressure gradient, membrane thickness, and gas solubility play a key role.

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