Breathing and Exchange of Gases Chapter-Wise Test 9

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which lung volume is the total amount of air the lungs can hold after maximum inspiration?

Tidal Volume
Vital Capacity
Total Lung Capacity
Expiratory Reserve Volume
3

Total Lung Capacity (TLC) includes Tidal Volume, Inspiratory Reserve Volume, Expiratory Reserve Volume, and Residual Volume.

Which of the following statements about the regulation of respiration is correct?

The medulla oblongata controls involuntary respiration.
The pneumotaxic center prolongs the duration of inspiration.
Chemoreceptors detect only oxygen concentration in the blood.
Respiratory rate remains constant regardless of blood CO₂ levels.
1

The medulla oblongata contains the respiratory centers that regulate involuntary breathing.

Which structure in the respiratory system plays a role in humidifying inhaled air?

Alveoli
Trachea
Nasal chamber
Larynx
3

The nasal chamber humidifies, filters, and warms inhaled air before it reaches the lungs.

Which blood vessels are responsible for gas exchange in the lungs?

Pulmonary arteries
Pulmonary veins
Capillaries surrounding alveoli
Aorta
3

The capillaries surrounding the alveoli facilitate the exchange of oxygen and carbon dioxide between blood and air.

What prevents the entry of food into the respiratory tract during swallowing?

Larynx
Epiglottis
Trachea
Pharynx
2

The epiglottis is a thin cartilaginous flap that covers the glottis during swallowing, preventing food entry into the respiratory tract.

Which of the following statements regarding respiratory mechanics is correct?

Intrapulmonary pressure is always higher than atmospheric pressure.
During expiration, the diaphragm relaxes and moves upward.
Air moves into the lungs when intrapulmonary pressure exceeds atmospheric pressure.
External intercostal muscles contract during expiration.
2

During expiration, the diaphragm relaxes and moves upward, decreasing thoracic volume and increasing pressure.

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

Oxygen diffuses from alveoli into pulmonary capillaries due to partial pressure differences.
Carbon dioxide diffuses from blood into alveolar air due to its high solubility.
The alveolar walls are composed of a thick layer of smooth muscle to regulate diffusion.
Gas exchange occurs across a thin respiratory membrane.
3

The alveolar walls are composed of a thin squamous epithelial layer to facilitate gas diffusion, not smooth muscle.

What happens to the diaphragm during expiration?

It contracts and moves downward
It relaxes and moves upward
It expands and flattens
It remains in a fixed position
2

During expiration, the diaphragm relaxes and moves upward, decreasing thoracic volume and pushing air out.

Which enzyme facilitates the conversion of CO₂ into bicarbonate ions in red blood cells?

Hemoglobin
Carbonic anhydrase
Amylase
Pepsin
2

Carbonic anhydrase is an enzyme that catalyzes the conversion of CO₂ and water into carbonic acid, which then dissociates into bicarbonate and hydrogen ions.

Which of the following statements about the structure of the respiratory system is correct?

The trachea is supported by complete cartilaginous rings.
Bronchioles lack cartilaginous support and rely on smooth muscle for constriction and dilation.
The alveoli are lined with thick layers of connective tissue for protection.
Pleural membranes are absent in mammals.
2

Bronchioles do not have cartilaginous rings; instead, they are composed of smooth muscle, which allows them to constrict or dilate.

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