Breathing and Exchange of Gases Chapter-Wise Test 6

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which of the following statements about oxygen transport is correct?

Oxygen is mainly transported as bicarbonate ions
Oxygen is primarily transported bound to hemoglobin
Most oxygen is dissolved in plasma
Oxygen is actively transported by RBCs
2

About 97% of oxygen is transported in the blood by binding to hemoglobin in RBCs.

Which factor primarily determines the direction of gas exchange in the alveoli?

Temperature difference
Partial pressure gradient
Enzyme activity
Lung size
2

Gas exchange in the alveoli occurs due to the partial pressure gradient of oxygen and carbon dioxide.

Which of the following statements about the respiratory centers is incorrect?

The medulla oblongata regulates the basic rhythm of breathing.
The pneumotaxic center shortens inspiration to prevent lung overinflation.
Chemoreceptors in the body only detect oxygen levels.
High CO₂ levels stimulate an increase in respiratory rate.
3

Chemoreceptors detect levels of CO₂, O₂, and H⁺ in the blood to regulate respiration.

Which of the following occurs during forceful expiration?

Diaphragm contracts
Intercostal muscles relax
Abdominal muscles contract
Both 2 and 3
4

During forceful expiration, intercostal muscles relax, and abdominal muscles contract to push air out of the lungs.

In which form is the majority of carbon dioxide transported in the blood?

Dissolved in plasma
As carbamino-hemoglobin
As bicarbonate ions
Attached to white blood cells
3

About 70% of carbon dioxide is transported in the form of bicarbonate ions (HCO3-) in the blood.

Which of the following is true regarding the Bohr effect?

Low pCO₂ promotes oxygen unloading
High H⁺ concentration increases oxygen affinity
High pCO₂ reduces hemoglobin’s affinity for oxygen
Low temperature favors oxygen unloading
3

The Bohr effect states that an increase in pCO₂ reduces hemoglobin's affinity for oxygen, promoting oxygen unloading in tissues.

Which of the following reduces hemoglobin’s affinity for oxygen, promoting oxygen release in tissues?

Low pCO₂
Low temperature
High pCO₂ and high H⁺ concentration
High pO₂
3

High pCO₂ and high H⁺ concentration reduce hemoglobin’s affinity for oxygen, promoting oxygen unloading in tissues.

Which of the following does not influence the oxygen dissociation curve?

Partial pressure of oxygen
Blood pH
Temperature
Nitrogen concentration
4

Nitrogen concentration does not affect the oxygen dissociation curve, while factors like pO₂, pH, and temperature do.

Which lung volume is the maximum amount of air a person can breathe in after a normal expiration?

Vital Capacity
Inspiratory Capacity
Tidal Volume
Expiratory Reserve Volume
2

Inspiratory Capacity (IC) is the total volume of air a person can inspire after a normal expiration (TV + IRV).

Which of the following correctly describes the transport of carbon dioxide in the blood?

Only dissolved in plasma
Mainly bound to hemoglobin
Mostly in the form of bicarbonate ions
Actively transported by RBCs
3

About 70% of carbon dioxide is transported in the form of bicarbonate ions (HCO₃⁻) in the blood.

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